UIBarButtonItem with color?

Question: Is it possible to have a red UIBarButtonItem?
Answer: If anyone is looking for code to exactly duplicate a simple UIBarButtonItem:
UIButton *button = [UIButton buttonWithType:UIButtonTypeCustom];
[button setBackgroundImage:[UIImage imageNamed:@"delete.png"] forState:UIControlStateNormal];
[button setTitle:@"Delete" forState:UIControlStateNormal];
button.titleLabel.font = [UIFont fontWithName:@"Helvetica-Bold" size:12.0f];
[button.layer setCornerRadius:4.0f];
[button.layer setMasksToBounds:YES];
[button.layer setBorderWidth:1.0f];
[button.layer setBorderColor: [[UIColor grayColor] CGColor]];
button.frame=CGRectMake(0.0, 100.0, 60.0, 30.0);
[button addTarget:self action:@selector(batchDelete) forControlEvents:UIControlEventTouchUpInside];

UIBarButtonItem* deleteItem = [[UIBarButtonItem alloc] initWithCustomView:button];

And delete.png is:
Comment: One additional note : you need to add QuartzCore library to your project and import it in your class to use the CALayer methods.
Comment: To save others having to look it up: #import
Comment: I think the default corner radius might be 5.0f instead of 4.0f.  Also, people may also prefer to use a 1 pixel wide image to keep the image small.  This post was useful though, thanks!
Comment: do you happen to have this blue image?
Comment: Instead of adding a UIButton to a UIBarButtonItem you should just create a custom UIView and add that to the UIBarButtonItem.
Comment: @bdrobert but what about the addTarget - how do you press the UIView if it's not a button? Or should that be done on the UIBarButtonItem that wraps it?
Answer: Why not just :
[[self editButtonItem] setTintColor:[UIColor redColor]];

(on sdk 4.* , ios 5 and up)
Comment: Swift 3: `barButtonItem.tintColor = .red`
Answer: You can create custom UIButton with your desired look and initialize your UIBarButtonItem with it as a custom view.
UIButton *button = [UIButton buttonWithType:....];
...(customize your button)...

UIBarButtonItem *barButton = [[UIBarButtonItem alloc] initWithCustomView:button];

Comment: But this does not give you a UIBarButtonItem that matches iOS's default rendering, unless you're willing to painstakingly replicate iOS default rendering behavior as Scott does. If,  however, you want to depart from the default look then this is clearly the way to go.
Answer: You can set the tintColor property of a UIBarButtonItem in iOS 5. If you need to support iOS 4, check out this blog post. It details using a UISegmentedControl styled to look like a single button.
Answer: Using a custom image doesn't work as it just uses the alpha to render the button.
Answer: Okay, there is actually a much better solution to this, in my opinion, which involves less code and uses the native UI controls.
The trick is to use a UISegmentedControl, and remove all the segments except one.  (Can't be done in IB, has to be done programmatically).
Once you've done that, you set the tint colour, then create a UIBarButtonItem passing it the UISegmentedControl as a custom view.
This guy's used the technique to create a category of UIBarButtonItem which works brilliantly:
http://fredandrandall.com/blog/2011/03/31/how-to-change-the-color-of-a-uibarbuttonitem/
Comment: Great suggestion if you have to support 4.3 as I do. I'm going with the category as detailed in the link.
Answer: You can create a custom image for the button and use that. Else, if you have set the tintColor of your navbar or toolbar to red, the button items on these will also appear red.
Answer: If its the UIBarButtonItem of a UIToolbar
set this before your implementation in the file you want this code
@class UIToolbarTextButton;

Then change the toolbar buttons doing this:
   for (UIView *view in self.navigationController.toolbar.subviews) {
        NSLog(@"%@", [[view class] description]);
        if ([[[view class] description] isEqualToString:@"UIToolbarTextButton"]) {
            [(UIToolbarTextButton *)view setTintColor:yourcolor];
        }
    }

Answer: If using IB (Interface Builder), drag a UIView from the Library onto the UIToolBar, and it will generate a UIBarButtonItem with a custom view.  You can then add any other controls you want to it, e.g. UIButton, UILabel, UIActivityIndicatorView.
Answer: I wanted to add something to the highlighted solution.  If you do this subclassing, it will not execute storyboard-defied segues and selectors that are assigned to the UIBarButtonItem.  Further, the 'target' and 'action' properties are not set in the UIBarButtonItem so you can't access them from the subclass and assign them to your UIButton.
I worked around this by adding 2 properties to my subclass (using ARC):
@property (nonatomic, weak) id targetViewController;
@property (nonatomic, strong) NSString *segueIdentifier;

Next, in the init of your subclass, add something like this to the accepted answer code:
[button addTarget:self action:@selector(performAction) forControlEvents:UIControlEventTouchUpInside];

and a function:
- (void)performAction {
    if (_targetViewController && _segueIdentifier) {
        [_targetViewController performSegueWithIdentifier:_segueIdentifier sender:self];
    } else {
        NSLog(@"Requires targetViewController and segueIdentifier to be set");
    }
}

finally, in your main view controller that is hosting all of this, in the 'viewDidLoad', add this:
_fancyBarButtonItem.segueIdentifier = @"NewTransaction";
_fancyBarButtonItem.targetViewController = self;

Hope this helps someone else save time when they start down this path with Storyboards/iOS5
Answer: When you have UIBarButtonItem setup in a Storyboard, you have to set the tintColor in the viewWillAppear() or viewDidAppear() method (putting it in viewDidLoad() doesn't work for me...):
- (void)viewWillAppear {
    [super viewWillAppear];
    [[self editButtonItem] setTintColor:[UIColor redColor]];
}

Or in Swift:
override func viewWillAppear(animated: Bool) {
    super.viewWillAppear(animated)
    editButtonItem.tintColor = UIColor.redColor()
}

Note: tested on iOS 8/9.

UIBarButtonItem with color?


Output Voltage of OP Amp is not equals to Acl x Vin in LTSpice

Question: I have recently downloaded LTspice and when I am testing the LF351 and LM741 OP-Amp, I realised that the output voltage does not equal to the gain which should be -50. I have looked at the data sheet and the Vsat of the LF351 is around 13.5V and the LM741 is 14V. I am trying to get the design desired output which I think should be -25Vp but none of the OP-amps gave me the output. So, I am wondering why the gain is not (-R2/R1) in this case. Thank you in advance.LM741 OP-Amp
Comment: try -50* 0.025=-12.5Vp or 25Vpp but G* f=50* 75kHz= 3.75MHz GBW requirement must exceed this.  OA "101" error
Comment: I tried changing the frequency which has increased the output voltage. May I ask why does changing the frequency increase the output voltage or is it just a LTSpice thing?
Comment: unity gain stable OA's have a built in integrator cap to make it have a 1st order open loop response in order to have a stable closed loop response. The  GBW is an individual component spec where gain and bandwidth are tradeoffs and the product is fixed.  In order to make the the closed loop gain accurate the open loop gain must greatly exceed the closed loop gain. so gain of 50 is too high for this frequency of 75kHz. Better designs exist. LF351 has  Wide gain bandwidth : 4MHz but not wide enough here.
Answer: Note that the output voltage on the graph is not in phase with the input voltage, but lagging by about 90 degrees.
This means that it's not your feedback resistor controlling the gain, but a capacitance, somewhere.
LF351, and other unity gain stable op-amps, have what's called a 'dominant pole' added to them with an internal capacitor. This rolls off the open loop gain so that by the time the other internal phase shifts are getting significant, the gain has dropped below unity, so that it can be fed back for unity gain, and still be stable.
As a result of dominant pole compensation, your op-amp will act like an integrator, at surprisingly low frequencies if the gain is high enough. The figure in the data sheet that lets you know how much gain can be achieved at any frequency is the Gain Bandwidth Product (GBW).


User Experience Between App Installation and First Time App Opening

Question: I am interested in finding out key reasons behind drop offs between Install App stage to First Open Stage. So, usually if I get 100 installs then approx 60-65 go to the first open stage ( as per Firebase data) Why does this drop off happen and is there anyway to retarget those people who have installed the app but not opened it. Thank you.
Comment: From personal experience: some of them may have installed it because they might want to use it at some point, but not just yet. They saw the app, thought it may be interesting at some point, but have no use for it at this moment.
Answer: Because the First impression went wrong. User onboarding is the process of helping new users understand and experience how your product is going to help them achieve their goal. In your case, they might be don't know how to use it/ what are the benefits in your app.
9 best practices and strategies for perfecting your onboarding process

Interview users to understand why they're coming to your product and where they came from
Define what 'success' looks like for each of your customer use cases
Create and use hooks to get customers invested in your tool
Break items down and leave something to be discovered
Keep momentum by setting expectations and showing their progress
Use progressive profiling and reduce the friction for getting started
Build inflows that connect teams and create an 'onboarding leader'
Create educational and aspirational content to give hands-off support
Make sure you have visibility into when users are dropping off


How to virtualize an existing OS2 operating system?

Question: I was looking into virtualizing OS2. I know it's a little tricky to virtualize OS2 in the first place, but I was wondering If it were possible to virtualize an existing OS2? I was going to use Virtual box. I duplicated the hard drive from an OS2 machine, and I wanted to know if it was possible to make it a virtual image? so that I could run it on another PC. OR if that is not possible, could I just create a virtual OS2 on a PC FIRST, Then move all installed software and files from the physical drive to the virtual OS? thank you.
Answer: If you can take the OS2 hard drive and extract it as an image (via dd or equivalent), you should be able to write that image to a VHD or other VirtualBox virtual filesystem. However, since the VHD isn't simply the raw extract that you would get from dd, you might need to mount the target filesystem on a Linux VM first, transfer the raw OS2 image to that VM, then dd it out to the VHD. You should then be able to create a new virtual machine that has that VHD as the primary drive and boot from that.
The only problem, naturally, is that the underlying "hardware" of virtual machine would probably be different from what your source OS2 machine was. Chipset incompatibilities, graphics card, etc. However, I think that OS2 would fail over to some default modes at least on the graphics front.
In other words:

dd out the OS2 hard drive to a raw .img file.
Create a VHD and mount it on a Linux VM.
dd the .img file to the first partition of the new VHD.
Create a new VM configuration for OS2 and assign the VHD you created as the primary hard drive.
Boot new OS2 VM and cross fingers.


Basics of energy

Question:
I am not able to understand the second paragraph well. Please elaborate me anybody
Comment: Please be more specific on the sentence or sentences that you can't interpret.
Answer: The second paragraph tells us about how abstract the concept of energy is but also how naturally connected it is to the universe. The author is trying to convey that energy is some sort of a number that one can calculate using certain formulas (like $\frac 12 mv^2$ for Kinetic energy or $mgh$ for Gravitational Potential energy) for  objects in the universe, and that it has many forms in nature, but for some reason quite unknown to us, nature always tends to keep the total energy of the universe constant. You can convert energy from one form to the other, but never create or destroy it. This is what the author refers to as "wonderful property of our universe". Formally it is called - The principle of conservation of energy.
Answer: It is a typical and unfortunately quite popular way of introducing the concept of energy in a very obscure way. The problem with such an approach to the concept of energy is that one is trying  to convey one of the most important feature of the concept, before even trying to provide a hint about what should be measured or calculated. Quite a pity for an experimental science!
I strongly advise you to skip for the moment that paragraph, go ahead, try to grasp a first idea about the content of the whole chapter, and then you can go back the this second paragraph with some possibility of assigning some meaning to it.
Just to provide you a trailer of what you could find in the next pages, presumably the author will introduce a couple of scalar quantities, named potential and kinetic energy,  both depending on the instantaneous configuration of a system and it will be shown that any change of each of them is always accompanied by an opposite change of the other.
Probably some chapters after, it will be shown that the same concept may be extended to deal with much more complex physical systems like fields, macroscopic objects with invisible atomic elementary units etc. In my opinion, anticipating so much the result is not very useful from a pedagogical point of view.
Comment: 's as you have told me I have gone through the whole chapter and studied about different forms of energy and few laws. But they haven't mentioned about the fact that what is the significance of any body having energy in itself. Is it only that it possess energy so it can transfer it through work? And as mentioned in the paragraph about the scheme by which they were able to quantify energy further in the topic nothing is mentioned about that scheme any more.
Comment: @RifatSafin  Is it a chapter on mechanical energy or thermodynamical energy?
Comment: Mechanical energy

Basics of energy


Move documents and retain the metadata

Question: I need to move 100's of documents from one SharePoint environment (2010) to another (2013).  Is there a FREE gui tool to do this?  I do not have direct access to server so PowerShell isn't an option at the moment.
Answer: Here you go! This should work fine! It also includes metadata
http://www.messageops.com/software/office-365-tools-and-utilities/office-365-sharepoint-migrator/
Answer: The Content Migration Wizard on CodePlex is a GUI tool and it is free, but you need to run it on the server. The GUI just generates the required PowerShell.
You could open both the 2010 and the 2013 libraries with Windows Explorer, then drag and drop. That's free, but the metadata won't be retained.
I doubt that there will be any free tools that do all you require and that can be used in the browser client without touching the server in some way.
If migration between environments is a business requirement, then get the people involved who DO have access to the server and run something like the Content Migration Wizard.

Move documents and retain the metadata


Excel - working with multiple workbooks

Question: Got about 50 workbooks that cannot be merged but need to make the data available in a nice easy way.  Aany ideas how to open and close multiple workbook modally i.e control remains in some interface / menu window?  all workbooks have multiple sheets and need to be opened read-only.  thanks
Comment: Do they all have the same structure?  Are you trying to summarize / find data within them?
Comment: What do you mean they can't be merged?  Why not run a script to merge them into a separate read-write workbook?  Why would you want to open 50 workbooks all at once - that doesn't seem nice and easy.  Give us more info.  If it were me I would merge 50 workbooks into one workbook, one worksheet per workbook.
Answer: It sounds like you just need to access the data from all your workbooks in one sheet.
You can use the following syntax to access the value of a cell in an arbitrary workbook/sheet.
<code>=[workbookname.xlsx]sheetname!$D$10
</code>
Here's a link for more information.
Comment: +1 That definitely does sound like a more logical approach than opening 50 workbooks.
Answer: Maybe the simplest to use is a good program launcher.
The article Best Free Program Launcher lists many free launchers (see also the comments).
After a quick look at some screenshots, maybe your best bet is 8start Launcher, but as I said this was after taking a (too?) quick look.

Excel - working with multiple workbooks


How to add more than 2 contacts for a household in npsp data import ? npsp managed package?

Question: How to add more than 2 contacts for a household in npsp data import ? npsp managed package ?
Contact1, Contact2 and an additional contact
Comment: Are you facing any specific problem?
Answer: This is explicitly covered in the documentation (the parent page for this PDF is here):

As part of the import process, Salesforce automatically creates a
  Household Account for each Contact1 in the template. Later, when you
  go to add data to the template, you can adjust the template to
  accommodate more Household members if you have more than two people in
  the same Household. For each new Contact in the Household, simply add
  a new row containing Contact1 and include the new Contact in the
  Contact2 column. Salesforce will add that new Contact (in the Contact2
  column) to Contact1's Household Account. You can repeat this process
  for any additional Contacts in the Household.

Download the template, populate the data as described above, and the NPSP import process will take care of the rest for you.


MySQL vs Redis for storing follower/following users

Question: I'm trying to find the best candidate for storing the follower/following user data,
I was thinking initially to store it in Redis in a set where user -> set of user ids but then I thought about scenario where there is over 1 million or even 10 million followers for a user, how Redis would handle such a huge set? also there is no way I can do pagination on a set in redis, I have to retrieve the whole set which will not work if a user wants to browse who following after him.
If I store it in MySQL I can definitely do pagination but it might take a long time fetching 10 million records from the database whenever I have to build the user feed, I can do this in old batch fashion but it still sounds pretty painful whenever a user who has many followers will post something and then processing these 10 million records would take forever just for fetching his followers.
Would it be worthwhile to store it in MySQL for pagination (mainly Frontend) and in Redis for the event-driven messaging which builds the activity feed?
Answer: It's a personal decision whether to use redis or mysql for this task. Both will have no problem with those 10 million records.
MySQL has the LIMIT x,y command for getting a subset of the followers from the database.
For redis you can use sorted sets and use the userid of the follower or the time user started following as score for an sorted set. And like MySQL redis supports getting a subset of the large sorted set.


Capture Keypress with modifiers in Python?

Question: So I have a macro style keyboard that comes pre-programmed for a specialised piece of software, I want to use a Pi to take those keypresses and translate them to OSC, which I have a python library for, however I can't find anyway to capture keyboard presses that include modifier keys, for example, 'c' does x, 'alt c' does y, 'cntrl c' does z and so forth. Everything I can find is either for graphic environments (This will be run on a headless server) or for a single character with no modifiers, it mainly the modifiers I am struggling with. Whats the best way of doing this? I'm happy if the detection is done in something other than python but would prefer python for speed reasons (So I can open one OSC connection at the start instead of with each command).
Answer: you can use curses library in python. (https://docs.python.org/3/howto/curses.html)
each keypress returns a number. 'c' is 99 and 'C' is 67, so you can use this to check when Shift+Key is pressed.
try this code to get the letters code:
damn = curses.initscr()
damn.nodelay(1) # doesn't keep waiting for a key press

try:
    while True:
        c = damn.getch()
        if c > 1:
            print (c)

I used it to get 'w' and 's' key presses, so this is my code:
while True:
    c = damn.getch()
    if c == 119: # W key
        sleepTime += 1
    elif c == 115: # S key
        sleepTime -= 1


Unity 8 not working with NVIDIA graphics card

Question: I am on Ubuntu 16.04 (Xenial Xerus) and have heard that, with this distribution, I would be able to get a better look at the Unity 8 and Mir desktop interface. I understand that it is still buggy and in development, but I have read a lot of good things about it and wanted to try it for myself. The laptop I run Ubuntu on has an NVIDIA Geforce 940M and has the latest graphics drivers from NVIDIA (so they are the proprietary drivers). When I first tried to install and switch to the Unity 8 desktop, I was greeted with a blank screen followed by a mostly frozen login screen where I could do nothing but suspend or shutdown my computer. Tried reinstalling, making sure I followed the directions to the letter, but with no avail. I decided it was probably that the proprietary driver I was using were not yet fully supported, so I switched back to the Intel Nouveau drivers, rebooted, chose Unity 8 instead of the default desktop, and was met with a blank screen this time. Not even a frozen login screen, just completely black. Is there no way I will be able to test Unity 8 on this computer, or is there some trick with NVIDIA graphics and/or Nouveau that I have not been able to find yet?
Comment: Can you disable the nvidia card in the firmware (BIOS/UEFI) and use the embedded Intel GPU instead?
Answer: It seems the next version of mir (v0.25) will support nvidia.
See bug #1628478 at https://launchpad.net/mir/+milestone/0.25.0.
The bug milestone was changed to 0.25 from 0.26 a few days ago which makes me think that much progress was made and hopefully an 0.25 release is imminent.
Answer: To test Unity 8, it requires Mir support, which is currently only partially implemented in the proprietary Nvidia drivers and at this time not enough to run Unity 8 / Mir properly.
In my case I installed anyhow (just to see what happens) according to this link
and what happens in my case, upon selecting the unity symbol at the login screen and then selecting Unity 8, is that, after entering my password, my screens (3 of the same connected to a GTX Titan X) turn black briefly and then show the login screen background again with the top status bar that you see when logging in on Unity 7, but no menu on the left and windows / alt keys don't bring up anything. So basically you can't do anything (AFAIK) but to select the power icon in the status bar at the top-right and "shut down" and then "reboot" - at which instance my computer switched 2 displays off and only its "main" display switched to standard text-based console mode with the reboot image with the dots showing and cycling through repetitively but that's where the process hangs, keyboard doesn't work either, so I had to do a hard-reset.
Hopefully Nvidia updates the Mir portion of the drivers soon to the point that Unity 8 works, I can't wait to test it out, looks very promising! (hopefully by the time Ubuntu 16.10 comes out in Oct!)
Answer: I feel your pain when it comes to test unity+mir with proprietary drivers. Since the previous answers mentioned why and when mir will work with nvidia driver, I would like to add that one can test the next version of mir before it comes to the stable repositories. You may add this ppa to test next version of mir (currently 0.25+):
<code>https://launchpad.net/~mir-team/+archive/ubuntu/staging
</code>


Show source code in HTML / wysiwyg editor in Events

Question: The source code button is missing from certain areas, such as event summary and event description. Any ideas on how to access it?
Answer: It's possible to have different config for ckeditor for civievent. See https://yoursite.org/civicrm/admin/ckeditor?preset=civievent. (Replace yoursite with your actual site.)
Comment: Thanks!  Even though we have CKEditor enabled, I think our events might be using TinyMCE because the wysiwyg ribbon doesn't match the settings I'm seeing in the ckeditor config
Comment: actually I think the issue is that link brings me to the config for CKEditor4 and the default (in admin/customize data/display preferences) is set to CKEditor5.  Is there a different link to the config for 5?
Comment: Oh that makes sense. Looking at https://lab.civicrm.org/extensions/ckeditor5 it says `a niche feature of ckeditor4 was a UI for configuration. The toolbar IS configured
through a javascript array so it would be possible to find a way to customise that
(but there is no current plan / demand for this)`. Another editor worth trying is summernote: https://lab.civicrm.org/extensions/summernote


understanding basic authentication with a 401

Question: I'm a little confused about Basic authentication in regards to web browsers. I had thought that the web browser would only send an Authorization header after having received an HTTP 401 status in the previous response. However, it appears that Chrome sends the Authorization header with every request thereafter. It has the data that I entered once upon a time in response to a 401 from my website and sends it with every message (according to the developer tools that ship with Chrome and my webserver). Is that expected behavior? Is there some header I should use with my 401 to infer that the Authorization stuff should not be cached? I'm using WWW-Authenticate header currently.
Answer: This is the expected behavior of the browser as defined in RFC 2617 (Section 2):
<code>A client SHOULD assume that all paths at or deeper than the depth of
the last symbolic element in the path field of the Request-URI also
are within the protection space specified by the Basic realm value of
the current challenge. A client MAY preemptively send the
corresponding Authorization header with requests for resources in
that space without receipt of another challenge from the server.
Similarly, when a client sends a request to a proxy, it may reuse a
userid and password in the Proxy-Authorization header field without
receiving another challenge from the proxy server. See section 4 for
security considerations associated with Basic authentication.
</code>
to my knowledge, Basic HTTP authentication has no ability to perform a logout / re-authentication. This along with the lack of security of HTTP Basic authentication is why most websites now use forms and cookies for auth solutions.
Comment: You are correct. 'Logout' is fairly meaningless within the scope of Basic Auth because the security tokens are sent *in every request*. In essence, each HTTP request is individually authenticated. You can force a browser to stop authenticating, eg see http://stackoverflow.com/questions/5957822/how-to-clear-basic-authentication-details-in-chrome.
Answer: From RFC 2617:

If a prior request has been authorized, the
same credentials MAY be reused for all other requests within that
protection space for a period of time determined by the
authentication scheme, parameters, and/or user preference.

From my experience it is quite common to see browsers automatically sending the Basic credentials for subsequent requests. It prevents having to do an extra round trip for additional resources.


Should I be doing PID auto-tuning with my fan at 100% (Anet A8)

Question: I'm using an Anet A8 with Marlin 1.1.6.
I've read countless guides on PID auto-tuning and never saw that the fan needed to be on, but when I look at the Marlin source code's ANet A8 configuration (here: example_configurations\ANet\A8\Configuration.h) it states:
<code>  ...

  // ANET A8 Standard Extruder at 210 Degree Celsius and 100% Fan
  //(measured after M106 S255 with M303 E0 S210 C8)
  #define  DEFAULT_Kp 21.0
  #define  DEFAULT_Ki 1.25
  #define  DEFAULT_Kd 86.0

#endif // PIDTEMP
</code>
So, should activate the fan before running the auto-test if I wish to update the PID values in Marlin for my Anet A8?
Answer: You should run the fan at what you expect it to be at the majority of the time it is printing.  If you tune at 100% fan and never use a fan then it will be too aggressive, if you tune at 0% fan and use the fan then you will struggle to maintain/reach temperature.
Comment: Thank you, that completely makes sense and I think is an important tidbit that all bazillion of these guides should mention.
Comment: One last (possibly stupid) question: does it matter if there is filament in the printer when Auto-Tuning?
Comment: Ideally I'd think you should extrude when you tune but I'm not sure if that is possible.  Having filament in might help but most of it is going to ooze out as it heats up anyway.


Cannot have multiple monitor modes in new Kali 2.0

Question: In previous versions of Kali Linux, we could have mon0 mon1 ... on the same wireless card (wlan0). But in Kali 2.0 which says have an updated aircrack-ng tool and new way of having monitor interfaces like wlan0mon. Now the problem is what if i want another monitor mode on same wireless card. I googled checked out the forums where someone posted similar question but no help. Is there any way?
Answer: I think it's impossible to do it. I thought Kali Linux 2.0 is really good but after that I'm thinking it's a big fail. Change from wlan0 to wlan0mon is killer. Why? Many scripts will work on all version except 2.0 in Kali because wlan0mon. It's really sad and If we can't do more monmitors mode, I'm thinking, I will leave this distribution for some time.
EDIT: Some person said me kernel 2.6.31 or higher use virtual layer or something like that. Try to use help of command "iw" and u will see that it's might possible to add new monitors mode :)
Answer: indeed as anon said, now you need to use the "iw" command to create multiple monitors, it seems like "iw wlan0mon interface add monX type monitor" does the job, however at the moment there are some flaws to it, or it's just me being incompetent with the "iw". for eg. mon0 is inoperable when mon1,2,3... are working perfectly fine and i can't turn power saving off for monitors >0. other than that.. works fine


Bayes Theorem with joint probability evidence?

Question: If I am trying to compute the probability $P(Z\mid(A,B))$ using Bayes' Theorem, how would I expand the right-hand side, particularly the evidence $P(A,B)$ in the denominator?
Answer: I'm guessing that by $(A,B)$ you mean $A\text{ and }B$.
What you do with this might depend on what information you've got.
$$
\Pr(Z\mid A\ \&\ B) = \frac{\Pr(A\ \&\ B\mid Z)\Pr(Z)}{\Pr(A\ \&\ B\mid Z)\Pr(Z) + \Pr(A\ \&\ B\mid\text{not }Z)\Pr(\text{not }Z)}.
$$
So there's a question of whether to do something beyond that.  If you know, for example $\Pr(B\mid Z)$ and $\Pr(A\mid B\ \&\ Z)$, then you could replace $\Pr(A\ \&\ B\mid Z)$ with the product of those two probabilities.  But if you know $\Pr(A\mid Z)$ and $\Pr(B\mid A\ \&\ Z)$, then you could use the product of those instead.
Comment: Thanks for the answer. I was looking for a webpage that showed a right-hand-side with joint probability evidence but couldn't find one. Now, about going beyond the formula, I was reading about Naive Bayes classifiers, and I think you can simplify Pr(A & B | Z) to be Pr(A | Z) x Pr(B | Z) by the chain rule of probability and assuming conditional independence.
Comment: That works of $A$ and $B$ are conditionally independent given $Z$, but not otherwise.


Trying to design and build a system where water pump into multiple outlets (pvc) evenly

Question: I am trying to build a little irrigation system where my water pump distributes the water into multiple outlets.  I guess my question is how do I make sure the water flows evenly in all the pipes.  I am using Pvc for everything.  Any tips or suggestion would greatly be appreciated. Feel free to ask questions as my drawings are detailed. Thank you
Answer: In general to get the water to flow evenly to all three outputs you have to ensure that all the paths from the pump to all three outputs is the same including length. In addition what ever nozzle or outlet opening you have has to be exactly the same for all three. To achieve this you will have to split the three outlet flow pipes before you get to the outputs. Something like this:

I have made the above sketch to show how the paths from the split point to the outlets is the same length.
Now with that said if the distribution pipe inside diameter is large compared to the outlet nozzle and the pressure inside the pipe has a significant drop across the nozzle then the pipe path similarity and length as stated is less significant. What that means is that the manifold type outlets like you show in your drawing would work if they are close together and the pump maintains a head of pressure in the lines.
On the other hand if ends of the delivery pipes to the outlets is just an open ended pipe then the similarity of the paths will be important to achieve the same flow at each output.
Comment: Thank you for the response and drawing.  Why does the middle line in your picture extend further out then the other two though?
Comment: @JohnWang - I already wrote why. "I have made the above sketch to show how the paths from the split point to the outlets is the same length." Some extra length is consumed in the upper and lower lines to go up and down.
Comment: I agree with @Michael Karas for a system without flow / regulators all 3 pipes would need to be the same size and length. If regulators were added at each of the 3 they could be controlled as long as there is enough head pressure for the regulators to provide the same flow.
Answer: Can't be done in a pressurized system
This is a hard problem often encountered in engineering and there's no easy solution short of individual pumps or other rotating machinery.  If you're looking for the magic bullet "how to fit your pipes so it works", there isn't one.   If one pipe has more impedance than the others, it will flow significantly less.
If it was unpressurized, you could do it with a weir by segmenting the outlets.  But if you need head of pressure to run a sprinkler system, the weir idea will only work if the weir is at a much higher altitude to give the head you need.
Answer:
You can do this in many different ways here is couple ways should be easy enough to do:

First option is creating a evenly distributed free low system. this would take a bit more effort than second option.
Use something like a barrel right at the end of the water inlet as a water container before distributing the flow in to separate pipes. Make sure this container is perfectly leveled the and attach your PVC pipes as exactly same height as individual outlets. give the pipes minimum of 10 degree down angle for the first 6 inches or so than you can divert them any direction you like as long as you don't go up :)
This is the closest picture i could find to what i am trying to describe...

If you could use a elbow pointing down at the end of the inlet pipe it would eliminate the extra natural flow would feed the outlet pipe directly in the same line with inlet pipe.
Second option would be much more simpler, just use a manifold like the one in the picture below and regulate the flow by adjusting the ball valves individually
The only set back for the second option is if you are using a submersible pump without a pressure vessel you will wear out the submersible pump much more quicker since the rotary vane type of pumps would not perform well in pressurized systems without a pressure vessel specially with long pipes.
Answer: I have had success in a similar situation using an automatic regulating valve (also known as a flow limiter). The REG valve from flows.com maintains a constant flow rate (within a range) regardless of pressure. I believe it works with a spring loaded flow restrictor that closes the flow path as pressure increases.
These are simple inline valves that resemble a check valve.
see this flow curve.
Comment: Welcome. Please disclose any affiliation you have with the linked website. Otherwise this may get closed as spam.


How to understand the differences and similarities between the orders in Greek and Latin alphabets, for memorizing?

Question: Letters in Greek alphabet are ordered similarly to those in Latin, but not exactly the same.
Is there any reason for the differences?
I ask the question for finding a way to understand and therefore memorize the order based on Latin alphabet.
Answer: Phoenician abjad -> Greek alphabets -> Old Italic scripts (including Etruscan alphabet) -> Latin alphabet
There were many versions of Greek alphabet. Italic scripts were based on Western Greek alphabet, while later standardized (by Eucleides) classical Greek alphabet was based on Eastern variant of Greek alphabet.
Besides differences in spelling, there were also many phonological differences between Greek dialects. (You might also read Ancient Greek phonology.)
E.g. When Zeta letter (Ζ, ζ) was originally invented, it probably meant [d͡z] affricate, which later changed to [zd] 2-consonants cluster in some dialects.
Comment: Just memorize them. It is not too many characters. Japanese children have to learn about 3000 kanji in school :) .
Comment: @Arfrever They don't have to memorise them in any particular order, though – only the kanas.
Comment: Thanks. Is there any way to memorize the order in Greek alphabet, based on that for Latin and transliteration?
Answer: For the most part, the ordering is the same, inherited from Phoenician. But some letters are used for different purposes in the different alphabets due to different transmission routes (eta vs H, gamma vs C), and others have been lost in one or the other (Greek lost F, Latin lost zeta).
Both of them also introduced new letters over time, and put them at the end: Latin borrowed Y and Z from Greek, for example, while Greek invented psi and omega.


Get senders location via IP in email Header

Question: I have email headers of people I have never met with their IP.I need to know and validate their exact location as they expect to take money from me but I do not wish to be fooled.
Comment: Does this answer your question? [How to trace email?](https://security.stackexchange.com/questions/16562/how-to-trace-email), [Tracing the location of a mobile IP from an email](https://security.stackexchange.com/questions/122507/tracing-the-location-of-a-mobile-ip-from-an-email).
Comment: *"I have email headers of people I have never met with their IP."* With the proliferation of web based email, it's likely you have the IP of the Web Server. Even if it's an originating client IP, it can't be trusted.
Comment: "as they expect to take money from me but I do not wish to be fooled". This raises many read flags. They are probably trying to fool you (with plenty of explanations, surely). Do not give them any money!
Answer: As you have asked the question, the only possible answer is do not hope to be able to relyably do that
The problem in SMTP headers, is that any header could be forged, even if all cannot be forged at the same time. And free VPNs are great at presenting an IP address which is not the original one. So here is a simple possibility:

I am currently in a country with poor security reputation but I know free VPNs in England, Germany or France, and use a mail account in the same country
I use one of those VPN to connect the Webmail host

Then all IP addresses that you will be able to find in the mail will say that the mail originates from England, Germany or France...
And I was not even speaking of the From: address...


How do I transform images to specific image dimensions without distortion?

Question: I need to resize images to given width/length, but when I do this in photoshop my images come out warped looking. What should I do?
Comment: Editing to delete the part of the question about file size, there is not enough info to answer it and it is best handled as a separate question.
Answer: Simple answer is you don't.
You can not change the width and height of an image by transformation without warping the image unless you transform proportionally. If you need images which are not proportional to the original, the best solution is to crop the images.
If you wish to change the size of an image in a non-proportional manner without warping it, you must crop the image, not transform it.
Comment: I'm very confused why you say this Scott when I know you know what you're doing..
Comment: @Ryan -
Okay.. I should add... you can't transform an image other than proportionally without distorting it. I understood what the OP was asking and why "warping" was being introduced - images are not proportional.
Answer: There are a few ways to transform without having warping occur:
For dimensions:

Go to Image Size and make sure the "Constrain Proportions" box is checked before you change the height or width.
I'm not sure what you're editing but also Ctrl+T (Edit > Transform) and then holding the shift key down while you move a corner anchor.

For total size:

Save For Web & Devices and then on the top right click on the arrow for more options (Optimize Menu) and one of the choices is Optimize To File Size.

My suggestion:
When I do a JQuery gallery that requires the images be of the same size - generally for me this is only my thumbnails - I first do a proportionate scale making the smaller of the two dimensions to be whatever value I want it to be, then I crop the other dimension, then save for web.
So if let's say my full size image is 1350 x 780 and I want to do 120x120 thumbnails. I would go:

Edit > Image Size > Make sure Constrain Proportion is ticked off > Change height to 120
Then there are two options: Image > Crop > 120 on the height and pick if it would be best for center, bottom, or top to get cropped automatically. Or draw a 120x120 box so that you can position it exactly where the best crop would be.
Now go ahead and Save For Web and if you want a particular file size do the Optimize To File Size option.

I don't generally Crop my full size images but that depends on what type of jQuery code you've written. Just transform proportionately and it won't be warped.
Answer: I would advise either rescaling it proportionally or saving it at a fixed kilobite size while retaining the present quality to a fixed maximum file size.  I like the scaling option myself for technical things.  I like the fixed file size for things like facebook.  It depends on your software in mine the  utility is called scale and keep the keep proportional box checked.
Answer: If it's a logo or something very similar with minimal color, you can take the image and open it in Illustrator, and then use Live Trace.
Answer: open your image paint. Then select resize by pixel. Put the required in the Horizontal and vertical box. The save.


Assertion failure in Notification Call

Question: I am getting an error when I register with the notification server in debug mode on my iPhone, and looking for some ideas.
My call:
<code>[[UIApplication sharedApplication] registerForRemoteNotificationTypes:(UIRemoteNotificationTypeBadge | UIRemoteNotificationTypeSound)];
</code>
it returns:
Thu Aug 27 12:27:44 unknown SpringBoard[2866] : * Assertion failure in -[SBRemoteNotificationServer registerApplication:forEnvironment:withTypes:], /SourceCache/SpringBoard/SpringBoard-919.5/SBRemoteNotificationServer.m:633
Thu Aug 27 12:27:44 unknown SpringBoard[2866] : * Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'no connection found for environment development'
In reading several posts, I have tried the following:
Created a new app ID.
Re-created my notification certs
re-downloaded my development profile
Cleaned all targets
rebuilt with the new app config and cert
Has anyone run into this?
Thanks in advance!
Rob
Answer: You may find your answer at iPhone SDK Push Notification
Comment: Thanks, great link!  Unfortunately it didn't yield a solution to my issue.

Assertion failure in Notification Call


Infill is rough - how to enhance?

Question: My i3 MK3 is printing very well for solid parts of an object, but it messes up with infill.

As you can see in the image, the infill is broken into pieces and bends to that the surface becomes rough and the nozzle touches it next time it moves there, which probably does not make things better.
I've read the Prusa problem page, where they suggest three solutions:

change infill type
flexible filament (I'm using PETG, so this does not apply)
lower printing speed

I'm printing with 20% infill and I believe that this worked before at the same speed, so I'm tempted to say that both remaining options are options, but it should work without them.
It also seems to me as if the infill is thinner that ordinary walls. Is the extrusion speed lower in case of infill? Is there a way of changing the extrusion speed for infill?
Side note: my printer always tells me to upgrade to the latest firmware 3.5.1. Since I have just received the printer back from a warranty repair after the last firmware upgrade, I don't want to upgrade the firmware. Could the issue be related to firmware?
Infos requested from comments:
I'm basically using the Slic3r default settings for PETG. The only thing I adjusted is the temperature, since I'm using HDGlass PETG and there was a recommended temperature written on the spool. Relevant settings seem to be

Filament settings

fan speed min 30 % max 50 %
bridges fan speed 50 %
enable fan below 20 s
slow down below 20 s
min print speed 15 mm/s

Speed settings

Perimenters 45 mm/s
Small perimeters 25 mm/s
External perimeters 35 mm/s
Infill 200 mm/s
Solid infill 200 mm/s
Top solid infill 50 mm/s
Comment: how does the infill print speed compare to the perimeter print speed? If the infill speed is appreciably higher you will have failed bonding between layers, which is somewhat how it appears in the image provided. PETG likes reduced cooling, from my understanding (limited) which might also point to cooling fan speed comparison.
Comment: what makes smooth infill desireable?
Comment: @Trish: a) less noise of the nozzle scratching over the rough infill, making me feel uncomfortable that it might just tear down the whole thing. b) Stability of the final product as expected. c) After the infill, the will finally be a solid top. That top will look ugly when printed over a rough surface. Do you have that problem as well and you just leave it like that?
Comment: have you tried different infils? I like 3D infil, like gyroid or cubic. I know that some linear infils (triangle or square) sometimes do that as the lines pass over themselves.
Comment: Sure, I can try a different infill. I just don't understand why it works once and it does not work now. I'd like to have reproducible prints that work at first print. Otherwise it's a waste of material, energy and money. I don't want to pollute the environment trying new infills which might or might not work.
Answer: From your comments can be read that you print infill at 200 mm/s.
Know that 200 mm/s is ridiculously fast (like high travelling speed), close to the limits of printing on certain machines (for an AtMega)! It is hard for the filament to keep up at this speed. A value of 60 mm/s would be a good value to start experimenting. Your infill is not rough, it just failed printing. I have printed kilometers of PETG, normal print speeds for my PETG are recommended at 30-50 mm/s by my manufacturer; I get good results at 50-60 mm/s. On my Ultimaker 3, 70 mm/s is also feasible.

Note that the filament you use seems to have rather low printing temperatures (195-225 °C) as opposed to the PETG filament (co-polymer) I'm used to. The manufacturer does not specify advised print speeds (other than "high", but what defines "high"?), but this user posted some of his print settings for this material. The overall speed of 60 mm/s seems to support lower than 200 mm/s print speeds.
Comment: 60 mm/s improved much. 50 mm/s is almost perfect. Great to see that I don't have to decrease the overall printing speed.
Comment: Ridiculously fast - well, it was the default setting for PET. Is there a way to save this setting as part of the filament definition? At the moment I can only find this as part of the print settings, which means I always need to adjust this. However, I'd like to ensure that I decrease the infill speed every time I use PET as the filament.
Comment: @ThomasWeller Just change it and save it. At least that is possible in default Slic3r or Ultimaker Cura.
Answer: I have dealt with this on infill as well on multiple MK3s.
However, it was not the speed itself, but the hot end having difficulty extruding enough to keep up with the infill.
Some things to try:

Raise hot end temperature 5 degrees (melt filament faster)
Lower infill speed, it will not affect your overall print time very much (surprisingly)
A combination of the two above.

Good luck!
Comment: Yes, temperature does make an effect, certainly when you are using 2.85 mm filament, that needs more time to melt through to the core. But from experience I found that still with raising the temperature you hit a limit causing the line width to be smaller than intended. But a good additional answer! I wondered to add that myself yesterday, but limited the answer to the IMHO high extrusion speed. Welcome at 3D Printing.SE!

Infill is rough - how to enhance?


What are good approaches to cleaning up old projects?

Question: I've got some software that I wrote around 2 years ago and needs some features added to it.  I've realised that it's in an awful mess, and I have the urge to move everything around, tidy up, etc. I've read the Joel on Software article about not starting again, so whats the best way forward?
Comment: Which decisions from back then do you disagree with today?
Answer: You have three basic options:

If the app is very small and a real mess, starting again might actuall be your best bet.
Refactor.
Live with the mess and hack in the additional features.

Typically, option (2) is your best bet.
How much refactoring you actually do will depend on the resource you put in vs the value you get out. Questions to ask will include:

What time / budget is available?
How much modification do you anticipate in the future?
Who else will see the code? (ie. will messy code damage your reputation?)
Is anyone else expected to maintain the code?
What refactoring tools are available to help you?
What is your experience of refactoring?
What experience will you gain from refactoring?
What kinds of refactoring will give you the most benefits?
What automated tests already exist? Need to be written?
How much manual testing will be required?
How will you feel if you leave the code as it is?

In my experience, it is very easy to get into proper muddle during a refactoring session. The most important lessons that I've learned are to:

Do one thing at a time.
Take small steps.
Make good use of your source control (check in frequently + include comments).
Make use of automated refactoring tools.
Know the IDE.
Comment: I also would like to add to avoid having a broken state for too long. I've seen many open source projects quickly dying during an ambitious rewrite/redesign. A non-functional project kills motivation quickly.
Comment: Absolutely. Regarding ambitious rewrite / designs, I've fallen foul of this more than once. Now, I try to take things in smaller steps. I've added this suggestion to my answer.
Comment: I'd add - in your source control, put all the refactoring on a separate BRANCH. This helps doing a sensible stepwise as well as big-block compares. This can be invaluable if things turn to custard (WHICH THEY WILL).
Comment: @TMN: Ideally, yes. However, you don't always *need* an automated test. (1) If code has been developed without automated tests then it may not be easy / possible to retro-fit unit tests until you've already done some refactoring (2) It can be expensive to write tests before making trivial, localised changes. (3) Automated refactoring tools + IDE features can help prevent code breaking as a result of refactoring.
Comment: I'd also add that you shouldn't refactor anything that doesn't have a test written for it.  Resist the urge to fix everything and just focus on the areas that need to be changed to add the new features.  Once you have that done, then decide how much additional effort you want to put in to refactor the rest.
Comment: @TMN: But I do agree about refactoring to incorporate the new features first. That way, you're focusing on the areas that add most value to the application.
Answer: Well, at least refactor enough so the new feature can be added safely. I.e. don't make it even worse. The rest depends on motivation, budget and time constraints - but be aware to fully cleaning up a mess can take longer than originaly creating it.
Comment: This is of course the famous Boyscout Rule: always leave the code in a better state than you found it.
Answer: This time while fixing the things make sure to document it. Next time you will see the code it will be much easier to recall the things.
Answer: It depends, is it going to cost more time maintaining it because it's a mess, or to rewrite it so it's not a mess and easily maintained.  I'm personally going through this right now, I'm converting an intranet site to ASP.Net MVC3 because the old code was a pile of crap (that I wrote) because it was supposed to be disposable (yes, I should know better).  The old pile of crap is still here, and it's a headache adding features and fixing bugs.  MVC is beautiful and makes working on it actually pleasurable, so it's getting a rewrite.


Regarding editorial policy and attitudes of editors.

Question: I recently posted an attempted proof of Beal's conjecture on the Math stack exchange and someone said I should put it on the Math Overflow site for professionals. The attempted proof I wrote uses Elementary Number Theory and is not hard. I have seen many problems on the Math Stack exchange that seem very difficult and could be  'moved' to the M.O. site. Anyway I responded that I'm just an amateur and User 8spir said 'Surely you are joking'. 8spir then said ..,' more or less out of principle I do not debunk short solutions of famous problems.' ALSO 8spir said  'if this is posted on the M.O. site it should be closed and down voted massively'..So WHAT THEN WOULD BE THE POINT OF PUTTING THIS THEOREM ON THE M.O. SITE?? This kind of attitude of some 'valued' editors is extremely discouraging. Must an amateur have a great reputation before she or he actually proves anything important? If the Stack exchange websites really do welcome amateurs then they should put up with amateur attempts and offer non-patronizing advice..
Comment: Firstly, you're complaining about [some random person on the internet](http://xkcd.com/386/) who said something you don't like. This isn't going to get you very far - there are many users with varying opinions here. Secondly, your timeline isn't correct. The user quid said [Surely you're joking](http://math.stackexchange.com/questions/887815/about-beals-conjecture#comment1833876_887815) to 8pir, with respect to the (totally misguided) suggestion for you to post this on MO.
Comment: An attempt at a proof of a big result is neither a fit here nor on MO. It should be written up nicely and put on arXiv. Once you have done that, please do not ask about whether it is correct here or on MO. Instead, contact specific people who work in the area, and make sure to explain your methods very precisely in the email and why those methods have succeeded where others have failed. If you do not explain this well enough, your email will probably be ignored. If you are not able to explain it well enough, then you have in all likelyhood not actually proved the result anyway.
Comment: @Tobias I disagree. What you wrote might be true for long or deep proofs. But the qestion at hand is a one paragraph elementary attempted proof. *Mathematically*, the question is no different than many other elementary number theory questions about checking proofs. And attempted proofs like this should *not* be sent to experts. They can easily be debugged by students.
Comment: -1 for the accusal to the wrong person.
Comment: If you want to know why you were told to post to MO, you have to ask the person who told you to post to MO; there's no point whatsoever of asking here on meta. But I can tell you, DON'T post to MO; your question will be closed so fast, it will make your head spin.
Comment: As for Beal's question: my advice is get an introductory Number Theory textbook like Niven-Zuckerman-Montgomery or Rosen, and do every exercise in it. If you can't, then there isn't the slightest chance that you can settle Beal. But you might learn some beautiful mathematics on the way.
Comment: Sorry for my errors ; my complaint is important if this is close mindedness. Amateurs don't have a hope of proving some important theorem with this kind of reception. A common way to discredit a person is to point out errors that have nothing to do with the main point being suggested. The random comment was from quid or 8spir I'm not sure. And the 'surely you're joking ' comment ; it wasn't clear if it was to me or 8spir. If it was to 8Spir doesn't that imply the quality of what I wrote was rotten?
Comment: On "If it was to 8Spir doesn't that imply the quality of what I wrote was rotten?" Not necessarily. It says that it is not a good idea to post it on MO. As can be seen from my later comment there can be also formal arguments for this. See, I do not study such things in any detail out of principle. Possibly this makes me a "bad person" or something like this in your eyes, but form this it should be extremly clear that I make *no evaluation of your work.*
Comment: Attempted elementary proofs of difficult open problems will always be met with skepticism (though the skepticism may be slightly less if one has an established mathematical reputation). Such famous problems often attract amateurs who dream of becoming famous by solving such a problem. But is is extremely rare that such problems can be resolved by elementary means. Some readers may have the patience to help debug such proofs *if* they are well-presented. Your proof is not, since you do not define $H$ and $K$ in the second line, so it is impossible to make sense of the argument henceforth.
Comment: In addition to Gerry's advice, you might enjoy perusing Richard K. Guy's book [Unsolved Problems in Number Theory,](http://www.amazon.com/Unsolved-Problems-Problem-Mathematics-Intuitive/dp/0387208607) which constains many interesting unsolved problems, some of which will probably turn out to be much easier to solve than Beal's Conjecture. It is essential to keep in mind that Number Theory is notorious for having many easily comprehended problems whose only (known) solutions involve very deep mathematics (e.g. FLT).
Comment: My main point is why was I told to write my attempted theorem in the M.O. site; then 8spir said 'if this is posted on the M.O.site it should be closed and down voted massively'. What is the point of that??
Comment: Where did my last comments go? Why are they hidden?
Comment: Related: http://meta.math.stackexchange.com/questions/11902/does-mathematics-depress-the-study-of-p-vs-np
Comment: Thank you for the encouraging advice given. This is much preferable and enlightening than some of the disheartening comments I have received. I did not know a short attempted proof of a difficult problem should NOT be posted on these sites , especially by an amateur. Anyway the ENCOURAGING advice is VERY useful..
Answer: For eveybodies convenience, first, here is the full comment thread (with added emphasis)

you should ask this question in MO forum because it is the site for professional mathematicians.... –  8 pi r Aug 5 at 6:33
Sorry I'm only an amateur.. –  user128932 Aug 5 at 6:41
Surely you are joking @8pir –  quid 2 days ago
@quid: do you understand what OP asked? –  8 pi r yesterday
@8pir it seems they tried to reduce the Beal conjecture to FLT and want to know if the argument is correct. More or less out of principle I do not debunk short solutions of famous problems. Anyway, if this is posted on MO it should be closed and downvoted massively. –  quid yesterday
So 8spir ; what is the point of moving this attempted proof to the M.O. site if it would be squashed?? –  user128932 57 mins ago
@user128932 Could you format it so that it's a bit more readable? –  Joachim 17 mins ago

One can see the description of the conversation by OP is completely distorted as they did not realize they were talking to two users 8 pi r and me (ignoring Joachim as this happened later). Also, I feel that it is not only an "accusal to the wrong person" but the entire complaint is based on the massive confusion that 1, 3, 4, 5 were all written by the same user!
The comment 3, my first one, is clearly directed at 8 pi r, as can be seen from the @8pir, see How do comment @replies work?
In my opinion, to suggest to post this on MO is a bad advice. I meant to point this out. The precise formulation was chosen since I honestly was not sure if 1 was intended as honest advice or somehow humorous.
I think 4 and 5 are pretty self-explanatory (if one pays attention to who said what, 4 is 8 pi r talking to me, 5 is me replying to them).
Let us go to 6. It seems based on a misunderstanding. The situation is quite simple: 8 pi r thought (perhaps still thinks) it is a good idea to move it to MO. I think otherwise. I cannot see anything unusual or outrageous here. Possibly my comment 3 should have been clearer. Sorry about that.
Comment: I do not understand why this was downvoted. It is merely collection of data+timeline relevant to the original post.
Comment: @Martin Somehow you seem to have missed that only the first half of the answer contains data. The rest contains opinions (e.g. "in my opinion..."), which often attract downvotes, whether or not the opinions are wise.
Comment: An important point that is missed is why should an amateur's attempt at a famous problem be automatically closed off and not even looked at. What about the occasional person who may be extremely brilliant? An  amateur who might have discovered a short solution? If all amateur's are assumed to be lacking in skill unless they have degrees or 'go through proper channels' then no amateur can do anything extraordinary in math unless they have a 'PROPER' reputation.
Comment: @user128932 This is not, or at least not mainly, an amateur vs professional issue. Various people apply various "filters" to decide what to study and what not. The prior reputation of the author is one among several factors for most. If you want some accounts of people that have written about this matter let me know and I will try to come up with some links.
Comment: I think this is an issue related to the attitude of any field of study towards amateurs. It is like the real world 'almost' paradox;'No un- experienced workers are will be hired (for some job)'. I know there has been people claiming to be brilliant amateurs pushing poor work yet if most amateur work isn't even looked at based on  'principles' like user Quid or 8spir said then actually brilliant amateur work will be ignored. I read somewhere Galois's work on Group Theory might have been thrown out if a sympathetic mathematician hadn't noticed it.
Comment: How can any amateur complain in a productive and non-abusive way if some editors will say and do exactly what they will with seeming impunity. Has an editor-user ever been docked many reputation points for some kind of misconduct or unfairness. Or are my comments pointless..
Comment: @user128932 First, a detail: you using the word "editor" is somewhat unfortunate since it is not quite clear to me what you mean. Also you insisting on being an amateur is somewhat besides the point. Who knows what I am for example? (Okay, I claimed somewhere in passing I am a professional but who knows, who cares?) Second, if a post is delted as "spam" or "offensive" then this cqn incur a point-penalty; for continued abusive behavior one can get suspended. But this is rather for more severe cases. If you find a comment unhelpful or annoying you could flag it as "not constructive."
Comment: Any user with a lot of reputation points can comment or criticize any posting hopefully in a constructive way. Also a such a user can vote to shut down a posting , this is editing. Someone like quid can perform the function of an editor whether you call it editing or not.


Measuring human resistance with a DMM

Question: When I attach a Digital Multimeter (DMM) to read the resistance between my right and left hands, the resistance starts off high and reduces over time. It appears almost like "RC-type" behavior. Can someone explain to me what it is that I am seeing on the DMM in some detail?
Answer: It has nothing to do with any capacitance.  It's all about skin resistance.  The resistivity inside your body is much lower than that of the skin.  As a result, your measurement is really showing you the sum of two resistances thru the skin.
The main reason skin has higher resistance than the body internally is because the skin is dry.  However, the skin can get moister by sweating and external blocking of evaporation.  When you grip the probes, evaporation is blocked in the immediate vicinity, so moisture builds up.  Your body may also produce a bit more sweat when you grip hard.
Try licking your fingers before touching the probes and you will see the resistance reduced substantially.  You can also reduce the resistance by gripping harder.  That increases the contact area and also makes better contact.
Comment: @Jesus - the problem is that the human body is grossly nonuniform, so the term "human resistance" is not defined.  There's the infamous case of "body mass index" meters which claim to measure fat content via resistance but whose output varies significantly depending on stomach and bladder contents.
Comment: great answer! How would one go about measuring human resistance accurately then?
Comment: @Jesus, As Carl said, "human resistance" will vary widely over a number of factors.  Variation in skin resistance is actually one of the parameters measured by a lie detector (polygraph).
Comment: @Jesus The slow response you see could be related to the skin conductance level (SCL). SCL is the slow varying skin conductance value, changing over the course of minutes.  See my answer.  However your probes are too far apart for consistent skin readings and you could be just seeing some residual error voltages in the meter.
Comment: Whoever downvoted this, it would be useful to know what exactly you think is incorrect.  I have re-read what I said and still think it's right.
Answer: Just to add to the answer a DMM is not considered a good way to measure such a high impedance reading like skin conductivity.  A typical Galvanic Response Sensor (GSR) has the ability to adjust filters/rates and is optimized for high impedance measurements to reduce the signal to noise ratio.  DMM's will often pick up environmental noise on very high impedance circuits (including probe motion across changing surface contact impedance).
Also the DMM probe shape is not ideal for a good skin contact which makes reading fluctuate wildly and is not repeatable.  GSR probes usually consist of two bands or large pads for good contact area and are applied to fingers, palms or soles of feet.  These areas are considered to be the most reliable for measurement.
The combined changes between galvanic skin resistance and galvanic skin potential make up the galvanic skin response.  It is not simply just "skin resistance" but a mix of resistance and galvanic reactions.  A typical GSR will measure both the skin conductance level (SCL) and skin conductance response (SCR) as they vary with sweat gland (eccrine) activity due to stress, arousal or emotional excitement.
There is a lot of quackery too.  The background on E-Meter used in Scientology makes for fun reading.  The Mark VII Super Quantum E-meter will run you about $5000.  (Yes, Super Quantum!)
But there has been clinical trials using a standard GSR.  This type of study is termed Electrodermal System Response (ESR) or EDA (activity).  They have been used as a tool in lie detectors and in diagnosis of abnormal psychotic patients (C17 is normal and P5 has a psychotic disorder).

Experiments continue with trying to measure skin responses.  This project discusses how they tried to separate and quantify these biofeedback responses.

When measuring skin conductance, there is the skin conductance level
  (SCL) and skin conductance response (SCR). SCL is the slow varying
  skin conductance value, changing over the course of minutes. SCR is
  the fast varying skin conductance value, changing over the course of
  seconds. The SCR that rides on top of the SCL reflects a person's
  mental response to various stimulus. SCR has several statistics that
  are useful for psychologists. First is latency, which is the amount of
  time between the stimulus and the rise of the wave. Next is the rise
  time, how long it takes for the skin conductance to shoot up to it's
  peak. Amplitude is the height of the SCR. Half recovery time is the
  amount of time it takes for the wave to fall back to half it's
  amplitude.

To see how your DMM compares to a EDA meter try this device.

Measuring human resistance with a DMM


Header file for view controller not created with MonoTouch

Question: This question is the same as this Missing h-files and Assistant Editor not working because of it (monoTouch/MonoDevelop) but none of the answers work for me.  When I double-click the XIB file from monodevelop no header file is created in XCode 4.2, even after I edit the XIB in Xcode and re-save, or when I quit Xcode and monodevelop and re-open.  I have expanded every folder in Xcode and there is no ViewController.h file anywhere.
Answer: I've had this happen quite a few times :( The solution is to manually create the partial class in MonoDevelop, inherit from the UI class you need, and finally add the Register attribute.
<code>[Register("MyCustomView")]
public partial class MyCustomView : UIViewController {
    ....
}
</code>
Once you do that, and save your code in MonoDevelop it should automatically rebuild the xcode project file for you.
Answer: I had this same issue, and as of 5 minutes ago it seems to have resolved itself. I don't know what the direct reasoning for this was, but it started after I closed xcode, monodevelop and restarted my mac. It didn't work the first time I rebooted, but I noticed that there was another xcode project open when I double-clicked on the xib in monodevelop. So I closed the project and xcode again. Next time I double-clicked on the xib it was there!
So, my guess is it is some kind of fluke or system caching issue. If you haven't been able to resolve it yet maybe try doing a reboot so the system cache can be cleared and make sure you don't have another project open in xcode when you try to open the xib from monodevelop?
Answer: I have noticed that deleting the "obj" folder of your project often helps. In there MD is storing all the helper fiels required by Xcode. This folder is not properly cleaned if you "clean" your solution from the build menu.
Quit Xcode, delete the folder, double click your XIB and the folder will be recreated.


Is there a Chief Rabbi of the United States?

Question: Is there currently or has there ever been historically a Chief Rabbi of the United States? If not, why not?
Comment: IIRC I've heard [Rabbi Silver](http://en.wikipedia.org/wiki/Eliezer_Silver), head of [the Union of Orthodox Rabbis of the United States and Canada](http://en.wikipedia.org/wiki/Union_of_Orthodox_Rabbis), described as the chief rabbi of the United States, but that was never an official title (or practical power) of his.
Comment: Legend has it Rabbi Eliezer Silver was being driven someplace when the car was pulled over for speeding. The chauffeur tried to explain to the cop "but this is the chief rabbi of the whole United States!" -- and from the back of the car, Rabbi Silver shouted -- "and Canada!"
Comment: Also worth reading the Wikipedia page on [Rabbi Yaakov Yosef](http://en.wikipedia.org/wiki/Jacob_Joseph).
Comment: +1 I don't think there is but I'm wondering why not.
Comment: @Shalom, that's probably what I was half-remembering.
Answer: There has never been an official Chief Rabbi of the United States. Jonathon D. Sarna (in his American Judaism: A History. Yale University Press, 2004, page 105) explains this phenomenon thus:

But since there was no parallel Christian religious authority—no chief Protestant minister, no archbishop, not even a Catholic cardinal with nationwide jurisdiction—it was easy for opponents to dismiss any Jewish effort to create a chief rabbinate as "ridiculous" and antithetical to American ideals. Nor, given church-state separation, could any chief rabbi expect governmental recognition, much less the kind of authority that some European chief rabbis wielded. Finally, many Americans of the day, Jews among them, were deeply suspicious of strong central authority. The "tyranny of the majority," they feared, would soon come trampling down on the rights of the minority, be they southerners or religious reformers. As a result, all efforts aimed at electing a chief rabbi ended in failure, and the decentralized congregationalist polity that characterized American Judaism since the Revolution remained in place.

There were a number of US cities that had Chief Rabbis, but the last one, Rabbi Shalom Rivkin of St Louis, MO, passed away in October of 2011 (source).
Comment: It's happened on several occasions long ago that a large number of synagogues in NYC agreed on (or were prepared to agree on) a chief rabbi, who would probably have been *de facto* chief rabbi of the US in many regards. Rabbi Jacob Joseph held such a post briefly, and there had been talk and plans for Rabbi Meir Leibush Malbim Weisser to have done so as well. (Accounts differ whether Malbim declined the offer, or accepted it but died before relocating.)
Answer: Similar sentiment

The point is that most Jews have not shown much interest in surrendering even a wit of their religious autonomy to their clergy. The only place in the world where chief rabbis have real political power and wield enormous internal communal clout is, of course, in the one place where Jews are in the majority – the state of Israel.
In the decades that followed the combative downtown rabbinical troika, supporters of esteemed rabbis lavished the largely honorific title of "chief rabbi" of specific hometowns upon their leaders. In the interwar period, Rabbi Tobias Geffen of Atlanta was revered both in that city and all over the South. In more recent times, Rabbi Pinchas Teitz, who unquestionably held sway among his minions in Elizabeth, N.J., comes to mind. But if they – and other compatriots – had any power, it was solely in the realm of persuasion.
Answer: There was one Rabbi who claimed to be (see below) but there has never actually  been a chief rabbi in the United Sate. Chief rabbis in countries that do have them   are almost always political appointees who were appointed by the government for political purposes. The United States constitution would not allow for such a hire.
Even if there was  an internal interest in the Jewish community for someone to hold that position,  there are so many different Jewish groups in America, with such different ideologies that there is no way one person could be chief rabbi and accepted as such by all groups.
Rabbi Y. Vidorowitz of Moscow came to America in 1893. He succeeded in gathering a number of tiny synagogues together which  he was chief rabbi for. He then  announced himself as Chief Rabbi of the United States and Canada. When asked "who made you the chief rabbi of America?" he answered "the sign maker" when asked "and why of the entire United States and Canada?" he answered "because  there would never be enough unified opinion among all the synagogues there to band together and depose me!"
Comment: The Chief Rabbi of France is not a political appointee - he is elected by leaders of the community. And I don't believe that is the case in the UK or South Africa either. Do you have sources for your second line?
Answer: Marvin S. Antelman was Chief Justice of his Supreme Rabbinical Court of America in the 1970s.
But this had no governmental recognition as Chief Rabbi such as in the UK.
In Antelman's book To Eliminate the Opiate, Vol. 2 (2002) can be found a correspondence from the SRCA to the Supreme Court of Israel wherein the SRCA refers to itself as Beit Din Elyon of America:
<code>Our Court wrote an Amicus Curia and placed the following ad:
AMICUS CURIA ON THE KNESSET BILL (5757) CONCERNING THE VALIDITY OF CONVERSIONS BY CLERICS OF THE CONSERVATIVE, REFORM, RECONSTRUCTIONIST ANTI JUDAIC RELIGIONS
Prepared by: The Bet Din Elyon of America for the Supreme Court of Israel
The Torah was given on one mountain by one God to one people not four Torah's on four mountains to four peoples. God, as our scriptural text sources clearly indicate abhors pluralism:
"There shall be one law for the citizen and for the stranger who dwells among you" (Ex 12:49); "There shall be one law and one ordinance for you and the stranger who dwells among you" (Num. 15:16); "How long will you continue to be pluralistic? (Kings I:18,21); "Don't meddle with pluralism" (Proverbs 24:21).
For many years there has been a disinformation campaign  ...
</code>
The rest of the amicus may be found here
The signature of this amicus refers to the SRCA as a Sanhedrin Ktana:
<code> Moshe Antelman, Av Bet Din
R. Bernstein P. Goldsmith Z. Levitt
M. Blitz S. Hecht K. Meir
M. Brown C. Hershanov M. Morgenstern
S. Fishbain Y. Jacobson D. Nachmias
M. Friedman S. Kaftori Y. Silver
Y. Gersh H. Kranz S. Sorscher
Y. Gilner D. Lapin E. Sprecher
Y. Glasner T. Tzuker

POB 855 Brooklyn, NY 11219
A Sanhedrin Ktana founded in 5735 (1974) by disciples of the Moetzet Gdolai HaTorah

POB 50502 Jerusalem
including members of: Rabbinical Council of America
Rabbinical Alliance of America
Union of Orthodox Rabbis of US & Canada
Agudat Yisrael
Chabad
</code>
Regarding how far his halakhic authority extended or was received, perhaps one would look how some of his and his court's major rulings went over? Such as in

The aguna debate (SRCA ruled a beit din may issue a get on behalf of a recalcitrant husband when it is to his benefit)
SRCA's excommunication of Henry Kissinger

https://en.m.wikipedia.org/wiki/Marvin_Stuart_Antelman


How do I deal with Gavelkind inheritance?

Question: I have a minor problem - I started playing as the guy from Aquitane(the southern super-Duke) and now as he is in the fifth decade of his life, I am faced with the threat of losing all of my duchies but Aquitane, due to the stupid gavelkind law that cannot be even changed because France has restrictive laws. How do I deal with it?
Comment: Why can't you change your inheritance laws? I can see why Primogeniture might be off the table (it requires high crown authority), but what about other options?
Comment: I ended up changing to Elective, which is a different basket of trouble. I managed to get my second gen heir elected without issues, but the third gen is a problem - the kid was born several years after the second gen ascended, and I can't nominate him as heir for some reason. What's more, the various counts under me all vie for the heir status, meaning factions and all the like. What age must an heir be to be eligible for nomination?
Comment: You should ask that as a separate question, since this question is about gavelkind. The idea is that when someone Googles for "how do i elective", they'll get a focused question about elective succession. There's no limit on the number of questions you can ask, so go for it!
Comment: Nevermind, eventually I made him a count and he managed to get enough support that he is now main heir candidate.
Comment: The trick with elective is to appoint as many of your relatives as you you can as dukes. Then just hope they have high quality kids. Every duchy controlled by your relative gives you a potential successor of your dynasty. The more potential succesors the higher the chance that you'll get a good one!
Answer: Problem: once you die, your sons will split up your lands. Since you have more than one top-level title (duchy, in this case), your multiple sons will split into multiple independent realms.
Solution 1: MURDER. You have too many sons. Make terrible things happen to all but one of your sons. Cross your fingers and hope your sole surviving son doesn't die until after you do. ("Terrible things" include assassination, putting them at the head of a far-too-small army and sending them to war, making them the court chaplain and sending them to proselytize to the pagans, and rarely-available plots to kill.)
Solution 2: TREASON. If you only have one top-level title, then your oldest son gets that title, and your other sons will end up as vassals to your oldest son. It's time to become King of France. You'll need either a majority of the counties in France, or a claim on the French crown, or permission from the Pope to invade France (which will probably involve excommunicating the French king first). But before you can take that final step to acquire the French throne, you'll need to be independent from France itself; this can be made much easier if several other dukes are attempting to declare independence at the same time. (Try joining or starting the Faction for Independence?)
Note that your lands will still be split up among your sons, but at least your eldest son will be your other sons' liege. Your eldest son probably won't have a full demesne after the inheritance kicks off, but maybe you can pick up some counties elsewhere, via holy wars or pressing claims.
Solution 3: WAR. Your sons will end up as independent nobles from each other (as vassals of the King of France), but they'll all have strong claims on each other. Your eldest son will end up with all your money and the best lands, so have him go to war to reclaim the rest of your former lands! Make sure he gets enough money to hire mercenaries, and it will be even easier.
Note that if your liege has Medium Crown Authority or higher, you won't be able to do this. At Medium authority, wars between vassals are prohibited.
Solution 4: ....Peaceful discussion? Once per generation, you may change your inheritance laws. If all of your immediate vassals have a positive opinion of you, and they aren't at war with each other, and you've ruled for at least 10 years, then just change your inheritance law to something else. Primogeniture requires High crown authority, but you should always be able to get Elective. (Elective has its own troubles, but you should be okay for at least this one generation.) Primogeniture is the easiest succession law to control, but your pretenders will dislike you (a net -50 opinion penalty!), and you'll lose the +5 opinion bonus you had with your other vassals, but it's (usually) better than splitting up your lands. Also, switching out of gavelkind will reduce your demesne size a bit.
For more details, wander through the succession and gavelkind sections of the CK2 wiki.
Answer: There is another way to handle having multiple sons with gavelkind, make your younger sons bishops (either build churchs in lands you control, revoke the bishop title from someone, or conquer a county in a holy war which has a bishop/mosque in it). This will disqualify them from succession. If at any point your heir dies you can revoke this bishop title and they will become the new heir to the entire realm.
Comment: Tried this for multiple kingdom titles where one kingdom had primogeniture succession laws and the other gavelkind. I tried granting the younger son a bishopric, and various other titles as well, all to no avail. The younger son still remained the heir to the kingdom with gavelkind succession laws while the oldest son remained heir to the kingdom with primogeniture laws.
Comment: IIRC, if your main title has gavel and sub primo, the gavel goes to first son because gavel works that way and the subs have primo so they go to first as well.
Comment: Unfortunately, you can't disinherit sons via bishoprics anymore.
Comment: Ask the pope to nominate him for a bishopric (if under papal investiture) or just plain nominating him yourself (if free) still works iirc.


Invalid password, please try again

Question: I'm running an Ubuntu 16.04 machine on QEMU/KVM.
I created a new user, atww, using Settings/User Accounts on the VM.
The user account type is Administrator.
I used usermod -p atww atww to set the password of user atww to atww.
When I try logging in with atww and password atww I get "Invalid password, please try again"
passwd -aS | grep atww
gives
atww P 01/09/2018 0 99999 7 -1 which seems to be correct. Is it ?
Please help !
Many thanks, Arno
Comment: Try using `passwd` to set the user password
Answer: The key -p for usermod command indicates to update the user's password with its encrypted value. https://linux.die.net/man/8/usermod

-p, --password PASSWORD
The encrypted password, as returned by crypt(3).
Note: This option is not recommended because the password (or encrypted password) will be visible by users listing the processes.
You should make sure the password respects the system's password policy.

The solution is to use passwd username.
Comment: Thank you so much ! I used passwd as you suggested and got the problem solved.

Invalid password, please try again


How do I validate the html/css and JS code outsourced to an external company.

Question: We have outsourced the html and css design to an external company. We want to make sure the quality of code is good. What benchmarks can we set to achieve this.
Answer: Use lint tools:

csslint
htmllint
jshint

The source for css lint is also available at github and according to their docs, html lint should be available soon. The advantages of using the source are:

You can work offline
You can define your own lint rules
You can have your outsourcers integrate your rules into their pipeline to ensure they catch any obvious errors soon

Have a coding standard for both CSS and HTML and ensure that they're given to your outsourcers. Ensure that deviations from your standard are followed up on and the work rejected. Make sure that you follow this rigidly. As time goes on, one would hope that you get less errors, but the more you allow (especially early on), the more frequent (and worse) they can become.
Comment: add jshint to the list.
Comment: How do I run CSS lint offline? I have WAMP installed.
Answer: Make sure you specify in the contract what you will validate.

Browser support. Consider requiring that the code work in all the browsers that you require (not just Firefox or Chrome). This will go a long way to getting you something you can actually use. By far the most common problem is receiving code that works in one browser, and then when you try to actually deploy it, discover it doesn't work in any other browsers, and fixing it is very expensive.
Validate. You can require your service provider to provide validated code using various validation services. Google W3C HTML validator, and work out what version of HTML you will support. There are similar CSS validators. Neither guarantee quality-- but perhaps they will discourage some service providers from applying or doing a really bad job. At least it is a bar you can set
Hire an Independent Reviewer. If don't have the technical expertise, get someone on your side that can be part of the whole process in a very limited advisory role.
Demand Transparency and Early Delivery I like to try out vendors and test that early on. This means starting with a small project, seeing how they do. Request a small change to measure their response (communication, responsiveness, attitude, etc.). Get a independent party to review the work, and see how they react to the feedback. This will give you insights into how the relationship will play out long term.

Good luck.


Mining Bitcoin heats up my Computer. why?

Question: I am Trying to mining bit coins from last 1 year. but every time i turn on the mining it slows down my computer and heat it up very badly that it eventually stops working some times.
How To get rid of this?
Help Me Please.
Comment: Mining uses your computer's computation power - the more it uses, the more yiu're rewarded. If you don't want it to slow down your system, don't do it. Furthermore, Bitcoin cannot be profitably mined on home computer hardware since 2013 or so; you need specialized ASIC-based hardware instead. If you're mining today, it's either an altcoin (which is off topic here), or a scam.
Answer: All of the energy that is used in any computation eventually leaves the hardware as thermal energy. Bitcoin mining is an energy intensive computational process, so one of the by-products of it is thermal energy (heat). If you want to stop generating heat, you'll have to stop mining (or figure out how to dissipate the heat more efficiently).
Keep in mind that bitcoin mining is only profitable using specialized ASIC hardware (that generates a lot of heat). Mining bitcoin with your laptop/PC will just use up electricity (and generate heat), without any real chance of doing enough work for you to receive a reward.


Grout spacing for large format wall tiles

Question: I have selected large format Porcelanosa wall tiles (33.3 cm x 100 cm) for a bathroom. From the brochures I have seen, these tiles tend to be mounted with a very minimal, almost invisible grout spacing. Our builder has started to mound these using a more regular 3mm spacing, which I am worried will look odd. He said that trying to mount with a 1mm or 2mm spacing will result in the spacers compressing and making an even finish very difficult. Is this true, or is there some special technique needed for large format tiles with a small grout gap?
Comment: It's mostly a matter of design choices. The builder's reasoning is odd, though. Spacers are available in nearly any size (or can be improvised). My guess is that (s)he simply doesn't want to redo any completed work.
Answer: I think that 33.3 cm x 100 cm (13.1 inch x 39.4 inch) large format tiles will actually look good with a 3 mm (1/8 inch) grout line.
The builder is probably using clips to hold the tiles to the wall, and the ones I've used are thicker than 1 mm. These clips help make the tiles flush with each other as the tile adhesive/thinset dries. If they install them without using clips (or another system) it will be exponentially more difficult to install well.
If you want the grout spacing smaller than 3mm, I would ask the builder what the smallest spacing they can do without extra work with their clip system, and ask them if it's possible to use another clip system that would work better?
Comment: Additionally, the minimum grout line is dictated by the variation in size of the tile from the manufacturer. You can't use a smaller spacing than the variation in size allows.
Comment: It's not absolutely clear from the link, but it seems like the tile in question are rectified, and the recommended grout line can be as little as 1/16.
Answer: If the tile you chose is rectified, then you may use any size groutline you like, it's that simple. If it isn't, then most manufactures will recommend a 3/16 groutline due to tile variation. If he doesn't know to use rigid spacers to handle the weight or to use a mortar made for large format tiles that can support that weight, stop him now.


Translating "Can you give me a piece of cake please?" into Latin

Question: I am trying to translate the sentence "Can you give me a piece of cake please?" into Latin for a short story I am writing. I came up with the translation "Da mihi, quaeso, tortae portionem" (Give me, please, a piece of cake), but I am not sure if this is correct or natural. Can anyone provide feedback or suggestions for other possible translations?
Answer: The general structure looks fine to me. Instead of quaeso, you could also say amabo. See this thorough article on "How to ask politely in Latin."
What I would take issue with are your word choices:

torta is a Latin word (a form of the verb torquere), but it does not mean "cake." The typical word for "cake" is placenta.
portio does not really mean "piece," it is more like someone's share or allotment. Here I would suggest frustum (piece, bit), which is commonly used of food; alternatively you could also say fragmentum (if broken off the cake) or segmentum (if cut off).

So you might say:

Da mihi, quaeso, frustum placentae.
Comment: I'd be fine with _torta_ in a context like this; modern cakes are sufficiently different from ancient Roman _placentae_ that a loanword from Spanish would make sense.
Comment: @Sebastian Koppehel: Here, "da mihi" = "give (to) me" & "quaeso" = "I ask (for)", why use both? Is there a role for "sodes" ["si audes" = "if you dare/ venture"] = please? In films Roman soldiers and politicians are often portrayed as terse, peremptory or just plain rude. The media are not to be automatically believed but these traits tally with the attitudes of (some) exponents of power, in an autocracy. Would "please" & "thank you" have had much currency in the Roman world?
Comment: @tony *Quaeso* is a set phrase to mark a polite question and is not otherwise connected to the sentence (as the commas suggest). I believe *sodes* can be used in a similar way. The Romans certainly could ask politely if they had to, not least because very few of them were actually particularly powerful.
Comment: @tony But if you read Cicero's letters, you can see that even the senatorial class had ample occasion for genial and deferential language to cultivate friendships and political alliances. By the way, liber X of Pliny's letters contains numerous responses from emperor Trajan. [See for yourself](https://www.thelatinlibrary.com/pliny.ep10.html) how the most powerful man in the world talked to a particularly inept provincial legate, a.k.a. *mi Secunde carissime* ;-)


Object Selection options not showing in 2.8

Question: I am using Blender V2.8. I am a novice user. The options to Add, Subtract from selection which is supposed to be shown below the top bar are not visible on my interface. What am I missing?
Answer: Assuming that your problem is not fixed yet, and you are using the latest version of blender (Version 2.82):

If the header is missing like this

then just click on the arrow pointing down at the top-right of the viewport window to unhide it.

The texts were replaced by icons as shown below:

If the Header is missing and you can't find the arrow as shown

then right-click on one of the control buttons at the top of the viewport window to show a Options where you can find the "Header" options And activate the "Show Tool Settings" checkbox found as shown below.
Answer: Are you sure this bar still exists? All these options are available on the N panel > Tool tab. You can also find them in the Properties panel > Active Tool panel (second tab from the top).


Syncing individual app data with iCloud

Question: This is a stupid question, but I just got an iPad mini for Christmas.  I have an iPod touch, and want to sync my app data for my games, etc., across devices.  Does this happen automatically through iCloud?
Answer: No - iCloud doesn't let you choose things to sync so the developer of each app you run needs to decide how and when to incorporate support for iCloud.
It's not such a silly question since I can't seem to find any Apple web page that explains this plainly.
As you find things that don't work with iCloud, you can pester the developer (kill them with praise and high marks even if you feel you want to give them a bad rating since you can expect them to please their fans first if they have any doubts about which tasks to add to their apps).
Comment: Dang it; that's really quite annoying.  I don't know how I'll sync progress across my games now!
Comment: Now - you can [restore the backup from one device to another](http://apple.stackexchange.com/questions/10023/how-do-i-transfer-app-data-from-my-old-ipad-to-my-new-ipad) so that you sync initial save state, badges, etc... but it's not a full two-way sync that keeps things up to date for all apps.

Syncing individual app data with iCloud


Can't put stroke width or fill on a path

Question: I'm a newbie.
I traced a photo with live trace, it looked good. Then I expanded it, and I can't get these paths to fill or take a stroke width, whether its grouped or not.
I drew a rectangle and it looks good and shows a fill and stroke width.
Comment: You might get a good answer if you edit your question to show a picture example.
Comment: the traced result show only fills ... tracing could not predict the outline value of your artwork.
Comment: If you can't fill and stroke *that* path you need to determine what's special about it. Is it a compound path? A mask?
Comment: I would say thsi is impossible to answer because we have no clue what you have done.
Answer: Based on your layers panel in your screenshot it looks like you might have accidentally converted your shape to guides. Your layer icon is showing a blue box and typically it will preview the whole shape contained in that layer which would include your custom shape.

Guides are ignored in an icon preview. So I highly believe your shape is no longer an official "shape".
To undo this select your guide. If you can't View > Guides > Uncheck Lock Guides
Then Select the gude and View > Guides > Release Guide
Comment: that doesnt seem to be the issue because i had already deleted the extras when they showed up after editing with handles and adding nodes. i transformed the edited version away and deleted two duplicates, but the problem is still there. hmmm Thanks for the response though!
Comment: i found i had a rectangle around it i thought was just the artboard but it had anchors on it, i deleted them, but still no stroke weight showing, although i told it 9pt.
Comment: See my edited answer, your shape has been converted to a guide accidentally.