Can " were known" be considered as a copular verb?

Question: I have to analyze the valency pattern of this clause "These glorious full colour prints that resulted were known as brocade pictures". Can I consider "were known" as a copular verb followed by the subject predicative "as brocade pictures"?
Comment: 'I have to analyze the valency pattern of this clause' indicates that you're following a course in grammar (the grammar terrorists who hold a catapult to your head and say 'Parse this!' being few and far between). But different establishments choose different grammars. I've seen 'known as' called a 'phrasal verb' [English Club]. And 'be known as' called a 'prepositional verb' [The Writer's Harbrace Handbook, Brief Edition_Cheryl Glenn, Loretta Gray.] If Professor @John Lawler gives you _his_ take, your people probably won't accept it.
Comment: Sure, why not? Seems a fairly sensible way of looking at it. Whether you consider _know as_ to be a phrasal/prepositional verb or just accept prepositional phrases as possible subject/object predicatives (the linking verb being then _know_ alone) is up to you. Similarly, in the active "We know these prints as brocade pictures", it seems reasonable enough to call _these prints_ the direct object and _(as) brocade pictures_ the object predicative. (Or _predicative complement over the subject/object_, respectively, if you want to give them names that more accurately describe their function.)
Answer: The copular verb/linking verb is "were" (to be), the linking verb number 1.
It is followed by "known", the predicative complement. Here "known" is used as an adjective. "known" is followed by "as brocade pictures". Here I think the terms for this part will diverge. I would say this word group is a complement to the adjective "known".
I don't think that "were known" can be seen as linking verb. But today there are so many grammar systems with different views that everything is possible.
May I add that I don't use the term valency, though I know it. But I think verbs are not comparable to elements of chemistry. Verb constructions can be changed, one construction can be transformed into another one, and new constructions can be developed. So I don't like the mechanical view that verbs have valency.
Comment: In our course (I'm an Italian student)  we're using Longman "Student Grammar" and it uses this term. But I totally agree with you. So can I consider this valency pattern (or the verb construction) copular (linking)?
Comment: Go and find copula/copular/linking verb in the register of your grammar and study the grammar point "linking verb". I don't think that the Longman grammar has " to be known" in its list of linking verbs.
Comment: I suppose it's still the same basic principle if we contrast *I am FumbleFingers* with *I am **called** FumbleFingers*. The former reflects standard examples of copular usage *(X [to be] Y)*, where ***X*** and ***Y*** are in some sense being "equated" (the predicate following the copula expresses *shared identity*). But I note that [Wikipedia lists two more types of predicate](https://en.wikipedia.org/wiki/Copula_(linguistics)#Meanings) (expressing *membership of a class*, or *some property, relation or position*), so I guess ***called FumbleFingers*** fits in there somewhere.
Comment: That's the problem. But according to your explanation and my book,  the whole clause is "copular" and the copular verb is "be" with "known as brocade pictures" as its subject predicative.
Comment: ...but I think we can safely dismiss the idea that ***be called*** is in any meaningful sense a "phrasal verb".
Comment: But thinking about it  - I think one may call any verb + adjective/ complement noun to the subject  a linking verb.
Comment: Then I think the linking verb is "to be known as". You can add  nominative as in "He was known as Robin Hood".
Comment: I think that's the right answer.


How to provide ubercart discount coupons only for specific users

Question: Anyone can say how to provide ubercart discount coupons only for applicable users and not for the other users ?. For example if a user from texas, then the admin can provide a coupon code only for that texas user and  it should not applicable for other out of texas users . please reply ASAP if anyone knows . thanks.
Comment: how are you determining that the user is from texas? based on their account information or their ip address?
Comment: Hi schnippy thanks for your reply ,Actually the users can enter the credentials only at the time of checkout after adding the product to cart.They choose or select the country list in checkout page.
Comment: got it - so its not a question of when to display the coupon (which is how I would understand providing a coupon code) but more how do you validate it on the backend after they have entered it? is this right? you're not asking how to display it just for specific users?
Comment: Hi Schnippy thanks for your queries on this question , the validation process take over only by ubercart modules in backend, we are not doing any custom function on that section for coupon, Am not asking how to display it for specific user. Am asking how to provide it for specific users which are all those from texas. If the users out of texas should not be get benefit using that coupon.
Answer: What you are looking for is a custom hook_uc_validate_coupon function. Ubercart coupon module allows for custom hooks here:
<code>// Invoke validation hook.
  foreach (module_implements('uc_coupon_validate') as $module) {
    $callback = $module . '_uc_coupon_validate';
    $result = $callback($coupon, $order, $account);
</code>
So in your site module you would need to define a new hook function that validates whether the order (or possibly the user object?) is using a billing address from Texas. Roughly, clone the existing validation function and add logic to check the order for your conditions.
function YOURMODULE_uc_coupon_validate($code, $order = NULL, $account = NULL) {
<code>if ($order->billing_state != 'Texas') { // or however you want to handle this
   $coupon = new stdClass();
   $coupon->valid = FALSE;
   $coupon->message = t('This coupon code is only valid in Texas.');
   $coupon->title = t('Unknown');
   return $coupon;
}

.. rest of validation function
</code>
}


Windows Server 2008 - Non-Domain users can see my server shares

Question: Windows Server 2008 - Server Machine
Windows 7 Professional - Client Machine
I have a domain. It was setup by the client.  The shares on the server are restricted correctly when a user logs on to the domain and uses their workstation, I have a few groups setup to restrict some access but the groups are at their core "Domain Users".
The problem I am having is that when a user brings in a laptop with Windows 7 Pro on it,  they can type up the name of the server in the "Run Dialog" on the start menu like "\SERVERNAME\"  and access all of the shares freely... because they are not logged in to the domain there are no restrictions it seems.I have reviewed the permissions on the folders and they all have to be "Domain Users" and I have removed "Everyone" from the list of people able to see it. Guest access is also disabled...What am I doing wrong? Only group in the list is "Domain Users" isn't a domain user a user that is logged in to the domain? How do I stop non-domain users from seeing the shared folder?
I noticed this on Windows Server 2003 too at another time. I assume they both had similar security issues and neither were set up by myself so I am not sure what could have been enabled or specifically deactivated that makes this issue appear.
I am looking at the Security >> Permissions and not "Share Permissions" but wouldn't the security permissions stop read/write on non-authenticated domain users?
Comment: They can see the Shares or they can access the Shares? What are the Share permissions (not the NTFS permissions)?
Comment: "Thanks for the down vote everyone!" - You got 1 downvote. That's hardly everyone. Yes, it sucks but it's part of being here so get used to it and don't let it put you off.
Comment: Both. I am checking the sharing permissions in about an hour when I arrive on location. My guess is the current admin has it set as "Everyone"

Thanks for the down vote everyone! That makes for a good learning atmosphere!
Answer: There are two types of permissions on shared folders, and you haven't explained which set you're looking at - and you haven't explained if the non-domain users can actually read files, or if they can just see the share names.
I'm guessing that you've examined the NTFS permissions on the files and folders, and those don't allow "everyone". But I bet that your share permissions (which are set in a different place) are set to allow "Full Control" to "Everyone". That's not a big issue - the more-restrictive set of permissions will mean that these anonymous users can't do anything else besides read the names of the share.
That's my guess, based on what you've said.
However, if they can access and read the actual files, then either you're missing something in the NTFS permissions, or they are successfully authenticating to the server. If their local username on the non-domain machine is the same as their domain username, and the password is the same, the client may be attempting (and succeeding) at passing NTLM authentication.
From the server, why don't you bring up Sessions under Shared Folders in Server Management and see what's going on from that perspective?
Comment: Also thank you for the tip about bringing up sessions, that revealed a lot of useful information for us.
Comment: I am looking at the "Securit >>Permissions" not Sharing Permissions

These are excellent suggestions.  I stumbled upon the "Share Permissions" after writing this. I am going to look in to it shortly.  The local user name and password is not used as a domain user id and password so it wouldn't be that one.

The (non-domain) user is in fact able to read/write even though the Security>>Permissions does not have "everyone" in it.  They only contain "Domain User".

I will post again when I look at the Sharing. But it seems as though something may still be wrong besides that as they can read/write?
Comment: Yes, there's clearly something wrong - your understanding of the configuration or the situation must not match the reality. The user may have done a "net use" or the GUI "map a network drive" and supplied their domain credentials. Or there's a mistake or misunderstanding in what you've configured for permissions. The windows security model won't let a user without the proper token have access to an object (like a file) that has a DACL configured. Citation : http://msdn.microsoft.com/en-us/library/windows/desktop/aa374872(v=vs.85).aspx
Comment: Clearly... The user has not logged in to anything.  I have not been back to the site yet, I have tested this out on a 2008 install I did internally to try to prove it out, and if I set the sharing permissions correctly then everything is fine.  If I only set the NTFS permissions then there is mixed results.  That is the reality I am facing.

Thank you for your help mfinni, I believe this is the correct answer.


Plural vs Singular masechtot names

Question: Why are some masechtot names plural (e.g. gitin, kidushin) while others are singular (e.g. tomid, nida and shabos)?
Comment: Isn't this a question on terminology in general? Those realms of _halacha_ are known by the terms in singular and plural, respectively, for reasons which are probably explainable regardless of the _masechta_ names.
Comment: @WAF, _Rambam_ has _T'midin_, but it's _maseches Tamid_. Likewise, _Korban Pesach_ and _P'sachim_ (which latter I've heard explained plural because it's so-called _Pesach Rishon_ (chapter 1 through?? and 10) and so-called _Pesach Sheni_ (chapters ??+1 through 9) IIRC) and probably others.
Comment: @msh210 I think it's 1-4,10 and 5-9; the former deals with the holiday and chametz and the latter deals with the korban issues.
Answer: I don't know about Nida and Shabbat, but as far as mesechet Taanit I heard a really interesting explanation.
I'm clearly not doing the explanation justice here, but in the Talmud Yerushalmi, Mesecht Taanit, is called mesechet Taniot.  Because outside of Israel, you can not declare new fasts, and many of the fasts that were declared were optional based on historical circumstances. (i.e. Shmad)  The Gemora in Taanit 11b or 12b says that "There are No communal fasts in Bavel save for Tisha B'Av" So in Bavel, only Tisha B'av was a fast which could be declared and kept on the public level for all generations, and so they renamed the messechet to Taanit, instead of Taaniot.
Ramban writes (as quoted in the Ran):

אין שם תענית ציבור בבבל אלא כל התעניות שמתענין בבבל אינן אלא כתענית
  יחיד. לפיכך אינו אסור בחומר תענות צבור. והטעם מפני שהדיינין שלהם
  הדיוטות הם ולא סמוכין ולא היה להם נשיא שתהא גזרתו קיימת על כל ישראל.
  לפיכך כשהצבור מקבלין תענית צריכין לקבל כולן על עצמן כיחידים שכל אחד
  מקבל על עצמו, ומשום הכי אינו חייב לנהוג בו אלא כתענית יחיד. אבל בארץ
  ישראל שהיה להם נשיא, לא היו צריכין לקבל על עצמן לפי שגזירתו קיימת על
  כולן וכולהו בתריה גרירי.
There are no communal fasts in Bavel; rather, all the fasts that they
  observe in Bavel are merely individual fasts. Therefore, they are not
  bound by the stringent prohibitions of a communal fast. And the reason
  is because their judges are laypeople and do not have semichah
  (rabbinical ordination)* and they did not have a nasi (president)
  whose decree would be valid for all Israel. Therefore, when the
  community accepts a fast, they all have to accept it upon themselves
  as indivduals, everyone accepting it upon him/herself, and because of
  this, they only have to behave as on an individual fast. But in the
  land of Israel where they had a nasi, they would not have to accept it
  upon themselves, because his decree is valid for all of them and they
  all follow him.
Comment: +1. In your last line, do you mean R. Sherira Gaon? He does say (in his famous letter) that the order of the masechtos isn't significant, but I'm not sure where he says anything about the names.
Comment: @Alex thanks, I confused those two issues, as well as his name. :(

Plural vs Singular masechtot names


How to Remove Page From Magento 2

Question: This is my website "http://www.vitaminf.ir/gosmart2/women/tops-women/hoodies-and-sweatshirts-women.html" i want to remove "gosmart2" from my url how can i achieve this. my site is "http://www.vitaminf.ir" but whenever i navigate through any category or product page it navigate as ""http://www.vitaminf.ir/gosmart2/category/category-type/product.html" how can i remove from my url "gosmart2"
your ans is appreciable for me
Answer: If "gosmart2" is store code, then you need to do this.
You can disable store codes via admin from below path.
<code>Admin > Stores > Configuration > General > Web > URL options > Add Store Code to Urls > No
</code>
Run caching command after save configuration.
Comment: Hi Dhiren Vasoya, Thanks for ans my query. it i think "gosmart2" is not a store code but it's a template name. I'm new to magento & just start learning magento 2. my magento version is 2.1.6 kindly help me to rid this situation.
Answer: You have 2 magento installation in the server:

http://www.vitaminf.ir/gosmart2
http://www.vitaminf.ir/

Check both themes are different.
OR
You have 2 different websites under one magento installation. One is running http://www.vitaminf.ir/ and another one is running under subfolder with name gosmart2.

If there are 2 different installation then you need to copy the sub
folder to root and change the urls in core_config_data to
http://www.vitaminf.ir/.
If you are using one magento installation and run the website in sub
folder then you need to change the default store run to root and
change the url in core_config_data table.

How to Remove Page From Magento 2


Would this breach copyright on Dr Who?

Question: If I write a story about an alien time traveller from a dying race, with encyclopedic knowledge, who sporadically visits London, travels with young companions, occasionally saves Earth and other planets, and appears to change bodies periodically. Would this be a breach of copyright?
Answer: There is too little detail in your question to give a clear answer. In fact, to get an authoritative answer, you need to let a IP lawyer read the full story and give a legal opinion.
The answer depends on how you write the story.
Copyright gives the copyright holder control over derivative works, so if your story can be classified as a derivative work of Dr. Who, and is not covered by the exceptions that exist in copyright law (i.e. Parody, Fair use), then you would breach copyright.
However, if your story just happens to use a similar story framework as Dr. Who, but where the plotlines, settings and and personality of main characters are all different from Dr. Who, then it probably will not be considered a derivative work and you would be OK.

Would this breach copyright on Dr Who?


Weakly $p$-summable sequences in $L_{r}$

Question: By Bessaga-Pelczynski Selection Principle, it is easy to check that both $l_{p}(1\leq p<2)$ and $l_{r}(1<r<p^{*})$ contains no normalized weakly $p$-summable sequences. I do not know if it is the case for $L_{r}[0,1]$. My question: Does
$L_{r}[0,1](1<r\leq 2)$ contain normalized weakly $p$-summable sequences$(1<p<2)$? Thank you.
Answer: No, because $L_r$ has cotype 2 for $r\le 2$.  In fact, every bounded linear operator from $\ell_q$ into $L_r$ is compact when $r \le 2 < q$.
Comment: Thanks,Bill. But I am not sure the proof of each operator from $l_{q}$ into $L_{r}$ is compact. It seems that your proof uses the cotype.
Comment: For a proof that does not mention  cotype see $$$$ Rosenthal, Haskell P. On quasi-complemented subspaces of Banach spaces, with an appendix on compactness of operators from Lp(μ) to Lr(ν). J. Functional Analysis 4 1969 176–214.


Printer spooler spoolsv.exe crashes after user logon

Question: I'm facing problem with printer spooler on Windows 2008 R2. After user logon via RDP with printer redirection, process spoolsv.exe crashes with error:
Faulting application name: spoolsv.exe, version: 6.1.7601.17514, time stamp: 0x4ce7b4e7
Faulting module name: localspl.dll, version: 6.1.7601.17514, time stamp: 0x4ce7c718
Exception code: 0xc0000005
Fault offset: 0x0000000000062edf
Faulting process id: 0x2624
Faulting application start time: 0x01cdfe079e8452da
Faulting application path: C:\Windows\System32\spoolsv.exe
Faulting module path: C:\Windows\System32\localspl.dll
Report Id: 7d043444-7bfd-11e2-9ca1-00155d016800

This error makes redirected printers in all terminal session offline.
Client is using Windows XP.
Answer: My bet would be one of the redirected printers using an incompatible, out-of-date or just plain malformed driver.  Try removing the all client's printers, then adding them back one by one, until you figure out which printer driver's causing the problem, then update or remove the problem driver.


In general is it better to get critical, damage or health in bit dungeon

Question: I always go for damage but recently I've been losing far short of my expectations, and I was pondering if it was better to get something else or to get small amounts of everything.
Answer: It really depends on your preference and playstyle. There are no better or best stat build in Bit Dungeon.
If you want to play aggressively, you may want to boost up your Damage or Critical. But it requires you to dodge/block more attack to avoid losing health.
If you are playing defensively, you should build up Health. You will be safer but it could slow down your progress as well.
What's the difference between Damage and Critical? Which is better mathematically? – By James Of Da Peach
This is the information of stats in Bit Dungeon, provided by developer:
PotionFind - Increases chance to find potions from boxes etc..
LifeSteal - Steals .01 of the life steal per hit.
DeathStrike - Chance to instant kill normal enemies.
Chop - Chance to take off 25% of total life in one hit.
Cleave - Chance to do a double hit with normal attack Damage.
Proc - Chance to proc(Shoots your magic spell for free on hit).
Crit - Chance to do a Critical hit (Attack Damage + Critical Damage).
Defend - Chance to block all enemy Damage on hit.
RunSpeed - the movement speed of your character.
Attack - Normal hit Damage.
Critical - Critical hit Damage.
Armor - Reduces Damage by a percent.
Life - Increases max life.

Due to the formula of Critical hit (Attack Damage + Critical Damage), increasing Attack Damage seems to be a better choice because Attack Damage affects both normal attack and critical hit, while Critical only affects the latter.
There are also hidden stats bonus depending on the weapon type you are wearing:
Axe - +10 Chop
Hammer - +10 Proc
Blade - +10 Crit
Sword - +10 Cleave
Dagger - +10 Defend
Spear - Unknown

Comment: What's the difference between Damage and Critical? Which is better mathematically?
Comment: Please check the updated answer
Comment: Ok, thanks. (very) Useful information. +1 now, but I still like the idea of a mathematical explanation for which is better. :)
Answer: I think it depends on your skills.  I tend to beef up on health because I'm a little slow to dodge missiles and react and stuff.  I think if I had the reactions I did as a teen, I'd probably want to take criticals mostly.


Blue Screen of Death for Beginners Learning C?

Question: Someone I know wants to learn C, but run their own programs and exercises on a PC. Which is all well and good until we get to pointers. Is there a significant chance of them damaging the PC or crashing it?
Comment: This question may not be suitable for EE.SE.  Having said that, the chance is nearly zero with modern PCs. As long as you don't delete important system files. Use a virtual machine for added safety. You can even delete the system files inside the virtual machine. Just delete the virtual machine later.
Comment: Highly unlikely that under an OS an user space application has enough privileges to do damage. But it all depends what kind of application you are programming, for example a program that finds a file and deletes it can have a bug and it will delete all your files. Run your program under a virtual machine or other sandbox where it cannot do any damage if it scares you, but I don't recall anyone making so heavy precautions when learning C. Also, it depends if you use pointers to data, or pointers to functions, so will you read and write bad data, or jump to execute arbitrary code.
Comment: In DOS or Windows 3.1 maybe. Have them use a newer operating system.
Comment: I have done a whole lot of Windows PC programming, but the only times I actually damaged the PC was when I meddled around with PCBs connected to it and accidentally got 24VDC on the wrong line. (I accidentally connected my scope ground reference to 24VDC just the other week, the PC monitor went black but survived...) So I think your PC should fear the average EE far more than it should fear a newbie learning programming.
Comment: @AJN I posted it here because almost everyone here uses C, or C++. It's the de facto hardware programming language. Plus they will be moving on to a dev board at some point
Comment: This is not a C question, but a platform question.  That PC experiments might be preliminary to targeting an embedded platform doesn't change fact that the question being asked is about the PC platform, not an embedded one.
Comment: After Windows ME, all versions of Windows have memory protection. Even before that, they had *partial* memory protection, and the worst thing you were likely to cause was a blue screen. But is this a question for Stack Overflow?
Answer:
Is there a significant chance of them damaging the PC or crashing it?

I'll ignore the "crashing" aspect (no, that's why we have process isolation) for now, and focus on what is on-topic for an EE.SE site:
Damage could only happen if you somehow made the hardware do something that damages it.
You won't be able to do that with a beginner's toolset. Sure, if you work as super user (a beginner wouldn't do that) and access a badly written driver (why would a beginner access a driver directly?) and instruct it to do something harmful (whatever that might be), yeah. There's potential for danger.
Remember, unless you're writing an early stage for your boot process, or a kernel component for your OS, you never access the raw memory of your machine, so accessing memory doesn't have side effects aside from the interfaces to hardware your OS offers you.
That's one of the many reasons one would recommend that people learn programming on a "proper" PC instead of on a microcontroller if they intend to deal with memory: The absence of hardware access makes everything safe, and way easier to debug.
In reality, I've never seen a beginner do beginner things that broke a PC. Like, I've seen people seriously torture keyboards in frustration, but that's not really the point here.
Answer: In a modern PC running a modern OS, there is virtually no chance of actually damaging anything (apart from the keyboard and their ego perhaps).
Errant programs (null dereference or file errors perhaps) will normally be not responding or terminated or perhaps give a segmentation fault.
One place to be careful is with files where some data might get lost or corrupted (and then usually only if you are using fwrite() or fread() with seek) but provided they are not system files (which are normally protected anyway) then it can be a valuable lesson.
File handling is actually a very important thing to learn, incidentally, particularly in C.
As noted by Marcus Muller this is not true when doing code on bare metal with a development kit. I have seen quite a few of those become door stops when the I/O pins are driven when they should not be.


Why are all cores at maximum capacity if there is RAM still left to use?

Question: I'm running a regular Python program on a i7 with 64GB RAM. I have lots of repeats so I have about 10 instances of this program running at the same time. Looking at the system resourses (on ubuntu 18.04), I have all 8 cores working at 100% capacity but I'm still only using 22GB RAM. I'm curious, why are all cores at maximum capacity if there is RAM still left to use?
Comment: An unoptimized endless spinning loop like `while(true){}` will consume as much CPU as the OS will give it, but consume 0 RAM, because the program isn't asking for RAM.
Answer: I think your program is using all available processing power - that's why all cores are at 100%. But this doeasn't mean that all RAM has to be used. Ram is not a substitution for CPU, it's memory. Maybe your program just doesn't require any more memory - it doesn't have to use all of the memory all the time.
Comment: So if I'm understanding correctly, the CPU is the limiting resource - not RAM. But does that also mean I'll never be able to use my 64GB RAM, since the CPU will max out first and I should probably have just bought 32GB.
Comment: With this particular Python program you possibly may not be able to use 100% of your RAM. But there should be a way to use all of it somehow. You just need to find RAM intensive program to run.     In this case, it seems like CPU is the bottleneck. If this is some multi-thread app, maybe it could run faster on CPU with more cores.
Comment: I'm not sure if you have some specific task in your mind or just want to see how it looks when 100% of RAM is used. But you can try to find some RAM bench-marking software or search for RAM intensive software to try to utilize all of it.
Answer: On normal conditions for a core platform cpus are limited by their clock frequency (what depend on heat dissipation), instructions per clock cycle (ipc, related to bus width, https://en.wikipedia.org/wiki/Instructions_per_cycle) and therefore pipeline support mainly (https://en.wikipedia.org/wiki/Instruction_pipelining). How fast memory channels can support pipelines through data for instructions is important, if cpus are below 100% usage.
On Ubuntu 18.04 you could install netdata system logger that would show you that relation between cpu and memory usage within detailed charts on a web browser on localhost:19999.
While running your python program you then see how much cpu utilisation and ram usage this program needs for a period of time (default ~1/4 hour).
Virtualization or database management can be example for high memory usage with varying cpu utilisation.


Does "the town has reasons to be chosen" make sense or sound natural?

Question: In a competition to choose the site of a big regional event, a particular town stands out with a sufficient number of hotels, a wonderful environment, hospitality and other advantages. If I say, "The town has reasons to be chosen," does it make sense and/or sound natural?    I wondered if the sentence may imply that the town is insisiting to be chosen as the site.
Comment: What is it about the sentence that makes you question its fluency?
Comment: Wondered if the sentence is gramatically correct and may imply that the town is insisiting to be chosen as the site. Thank you
Comment: That's good - editing that comment into your question would improve the question. As for the sense of the sentence, yes, it's ambiguous - it could be considered a figure of speech such as anthropomorphism, or it could be taken as the simple reading. The sentence conveys the intended meaning so 'makes sense' in that respect, but InternetHobo's answer has a much more *natural* sounding rendition.
Answer: "There are reasons to choose the town." is probably better. It expresses that the reasons to choose the town exist, instead of implying that the town itself it actively trying to be chosen.


How do I add two secp256k1 keys together?

Question: I have two public/private keypairs, A and B. I want to add them together to get a new keypair AB.
I'd also like to be able to add the public keys of A and B to get the public key of AB.
How do I do this?
Comment: If you're using OpenSSL, `EC_POINT_add`.
Comment: You can be more specific about what you mean by "add together"? You can literally add the two public keys and the two private keys to get a new keypair.
Comment: @DavidSchwartz `You can literally add the two public keys ` Yes, that's what I'm looking for.
Comment: @DavidSchwartz Can I see an example ?
Answer: Most ecc libraries will have this function, but if you want to program it yourself, here's what you do:
First, compute the slope of the line containing the points A and B. Let A = (X_a, Y_a) and B = (X_b, Y_b). The equation for the slope is:
s = (Y_a - Y_b) / (X_a - X_b)
The resulting point, we'll call C = (X_c, Y_c) = A+B. Doing some math, you get:
X_c = s^2 - X_a - X_b
Y_c = Y_a + s (X_c - X_a) = Y_b + s(X_c - X_b)
If X_a == X_b, then it depends on Y_a and Y_b. If Y_a == Y_b, then A and B are the same, so really, you're just computing a point doubling (2*A). If Y_a == -Y_b (the only other possibility) then A+B = the point at infinity, or the identity. Usually, that's not a very interesting point for cryptography. Computing 2*A is a little trickier, but can be done. You're already doing that when you compute the public key from the private key with G anyway, so I'll assume you have access to something that lets you double a point.
Note all the operations are all field operations, so you have to mod by P for secp256k1 (FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEFFFFFC2F in hex).
Answer: Here is some python code you can reverse engineer
<code>def add(p, q):
    if p[0] % P == 0 and p[1] % P == 0:
        return q
    if q[0] % P == 0 and q[1] % P == 0:
        return p

    if p[0] == q[0] and p[1] == q[1]:
        if p[1] == 0:
            return [0, 0]
        l = (3 * p[0]**2) * modInv((2 * p[1]), P)
    elif p[0] == q[0]:
        return [0, 0]
    else:
        l = (p[1] - q[1]) * modInv((p[0] - q[0]), P)

    x = l**2 - (p[0] + q[0])
    y = l * (p[0] - x) - p[1]
    return [x % P, y % P]

def modInv(n, p):
    return pow(n, p - 2, p)

#some constants
P = 0xfffffffffffffffffffffffffffffffffffffffffffffffffffffffefffffc2f
x = 0x79be667ef9dcbbac55a06295ce870b07029bfcdb2dce28d959f2815b16f81798
y = 0x483ada7726a3c4655da4fbfc0e1108a8fd17b448a68554199c47d08ffb10d4b8

#example usage of the add function
g1 = [x, y]
print "g1 = " + hex(g1[0]) + " : " + hex(g1[1])

g2 = add([x, y], [x, y])
print "g2 = " + hex(g2[0]) + " : " + hex(g2[1])

g3 = add([x, y], g2)
print "g3 = " + hex(g3[0]) + " : " + hex(g3[1])

g4 = add(g2, g2)
print "g4 = " + hex(g4[0]) + " : " + hex(g4[1])
</code>


How to save a text file (CSV) with UTF-8 without BOM encoding in VBA (Excel)?

Question: So this was my initial question. The answer to my question below, seems to be that the only solution to get UTF-8 (and UTF-8 without BOM) encoding, is to use the ADODB.Stream object. The answer to my new question in the subject line is posted as a code.
I am sitting here and trying to Save an Excel sheet as a .CSV-file with a VBA macro.
However, I am wondering if it matters whether I use ADODB/ADODB.Stream or just .SaveAs Fileformat:=xlCSV. I have tried to Google it, and it seems like I cannot find an answer to which method is the "best". I would need it to be comma delimited, UTF-8, and double quotations ("") as text-identifier.

Is it correct that when you use Fileformat:=, it is not possible to SaveAs UTF-8, since the xlCSV is not using that encoding? YES, that is correct.
See my answer for the solution.
Comment: I suggest you.... try it and see! Note that CSV is just a text file so you could even just use text file writing methods.
Comment: Ditto what @Nick.McDermaid said. Give it a try. If you run into problems you cannot resolve, post your code and exactly what's going on & someone will jump in to help you.
Comment: Cheers guys :) I was just wondering about the pros and cons about doing it in these ways.
Comment: @Niclas: Perhaps you will edit your question and split it into a question and a separate answer? This would increase the readability by a lot.
Answer: thank you for posting this question and also the solution. It helped me a lot.
Yes, I also found that SaveAs does not save the CSV file in UTF8. In my case it uses shift-JIS. The adodb.stream worked well for me.
However, I am not sure why but I had to declare some constants (enum) you used in the code. (I am really new to VBA so maybe I missed something about why this happens). I added this in the beginning of the function, then it worked perfectly:
  Const adTypeText = 2
  Const adModeReadWrite = 3
  Const adTypeBinary = 1
  Const adLF = 10
  Const adSaveCreateOverWrite = 2
  Const adWriteLine = 1

I got the value from Microsoft docs.
Once again, thanks!
Comment: This isn't an answer to the question and should be deleted. If you are facing any related issue, then you can ask a new question while mentioning this particular question
Comment: @BalwinderSingh thank you for the feedback. What I wrote should actually be a comment to the question (or to be precise, to the answer, as you may have checked, OP answered his own question by editing it). I managed to use his solution with the modification I wrote above. I thought it can help somebody else too.  Problem is, I do not have enough reputation to comment. If you think it is better for me to copy OP's code and added my modification, kindly let me know.
Comment: My bad. As per the original edit, I thought you were facing some related issue. Now it makes sense after you edited it and it might help others who face similar issue. Cheers
Answer: So I came in the situation where I needed this code again, and I read the comments and Leonard's answer, which made me update my code together with better descriptions.
This code will convert your Excel sheet and save it as a CSV file with the UTF-8 without BOM encoding. I found this code on a website, so I will not take credit for it. CSV without BOM link
Option Explicit

Sub CSVFileAsUTF8WithoutBOM()
Dim SrcRange As Range
Dim CurrRow As Range
Dim CurrCell As Range
Dim CurrTextStr As String
Dim ListSep As String
Dim FName As Variant
Dim UTFStream As Object
Dim BinaryStream As Object

' ADO Constants
Const adTypeBinary = 1 ' The stream contains binary data
Const adTypeText = 2 ' The stream contains text data (default)
Const adWriteLine = 1 ' write text string and a line separator (as defined by the LineSeparator property) to the stream.
Const adModeReadWrite = 3 ' Read/write
Const adLF = 10 ' Line feed only - default is carriage return line feed (adCRLF)
Const adSaveCreateOverWrite = 2 ' Overwrites the file with the data from the currently open Stream object, if the file already exists

' Open this workbook location
ChDrive Left(ThisWorkbook.Path, 1)
ChDir ThisWorkbook.Path

' ask for file name and path
  FName = Application.GetSaveAsFilename("", "CSV File (*.csv), *.csv")

' prepare UTF-8 stream
  Set UTFStream = CreateObject("adodb.stream")
  UTFStream.Type = adTypeText
  UTFStream.Mode = adModeReadWrite
  UTFStream.Charset = "UTF-8"
  UTFStream.LineSeparator = adLF
  UTFStream.Open

  'set field separator
  ListSep = ";"
  'set source range with data for csv file
  If Selection.Cells.Count > 1 Then
    Set SrcRange = Selection
  Else
    Set SrcRange = ActiveSheet.UsedRange
  End If

  For Each CurrRow In SrcRange.Rows
    'enclose each value with quotation marks and escape quotation marks in values
    CurrTextStr = ""
    For Each CurrCell In CurrRow.Cells
      CurrTextStr = CurrTextStr & """" & Replace(CurrCell.Value, """", """""") & """" & ListSep
    Next
    'remove ListSep after the last value in line
    While Right(CurrTextStr, 1) = ListSep
      CurrTextStr = Left(CurrTextStr, Len(CurrTextStr) - 1)
    Wend
    'add line to UTFStream
    UTFStream.WriteText CurrTextStr, adWriteLine ' Writes character data to a text Stream object
  Next

  'skip BOM
  UTFStream.Position = 3 ' sets or returns a long value that indicates the current position (in bytes) from the beginning of a Stream object

  'copy UTFStream to BinaryStream
  Set BinaryStream = CreateObject("adodb.stream")
  BinaryStream.Type = adTypeBinary
  BinaryStream.Mode = adModeReadWrite
  BinaryStream.Open ' Opens a Stream object

  'Strips BOM (first 3 bytes)
  UTFStream.CopyTo BinaryStream ' Copies a specified number of characters/bytes from one Stream object into another Stream object

  UTFStream.Flush ' Sends the contents of the Stream buffer to the associated underlying object
  UTFStream.Close ' Closes a Stream object

  'save to file
  BinaryStream.SaveToFile FName, adSaveCreateOverWrite
  BinaryStream.Flush ' Sends the contents of the Stream buffer to the associated underlying object
  BinaryStream.Close ' Closes a Stream object

End Sub


How to achieve a hard edge at this geometrical intersection?

Question:
Im trying to make this edge appear smooth, soo that the faces on each side seem to meet up smoothly. But I want the green edges around this to be hard and sharp. I am using 3ds max, and this is the result.
Answer: Just apply a different smoothing group to the green polys
Comment: Hi Relidex I just tried what you suggested, and it seemed to be the same. I even turned on the hard edge display after and it calculated the same edges I did manually. Perhaps its a turbo smooth crease issue?a


Maximum likelihood estimation for Gaussian mixture

Question: When doing maximum likelihood (ML) inference on a Gaussian mixture model (GMM), Bishop notes in PRML that if there is more than one mixture component in the GMM and the mean of one Gaussian collapses onto a data point, it is possible for the likelihood function to blow up to infinity as the variance of that Gaussian shrinks to zero. (This could happen, for example, when there is one "obvious" cluster and a single data point very far away, and there are two mixture components.) I understand that we are overfitting the training data by claiming the variance of one component is close to zero when it really may not be. But does doing ML on a GMM pose any theoretical issues that could prevent one from finding a solution? Isn't it still possible to find a solution using the EM algorithm?
Comment: I don't think it'll completely answer your question, but some points on this topic can be found here: http://stats.stackexchange.com/questions/153254/convergence-of-em-for-mixture-of-gaussians/153256#153256
Answer: First regarding the practical issue of vanishing variance most implementations of GMM will have a limit on how small the variance can get, you can set the minimum to some small value based on your specific problem.
Secondly EM is guaranteed to improve on the objective function (Likelihood in the case of ML) or remain the same.  After each iteration the parameters are updated. If the parameters have converged you have a local optimum, which is your final solution. The short answer is there is nothing preventing you form finding such a  solution - If you have the necessary precautions to prevent variance going to zero.
Comment: @VivekSubramanian I would not consider variance going to zero (likelihood to inf) as converged, it is a degenerate solution.  I do not think it is the same as the label identifiability issue - in that case you "actually" have a non-degenerate solution except the labels are reversed.
Comment: The problem is that there *is* something from preventing you from finding a fixed point: if the algorithm begins to approach a degenerate solution (i.e. as solution where the variance parameter equals 0 for one or more Gaussian components), it will never converge. On the other hand, if it approaches a finite local maximum, it will converge.
Comment: @CliffAB - does my edit address your last point?
Comment: It's not very clear what you mean by saying "you have solutions at every iteration". I think I know what you're trying to say, but if I'm right, then this statement is not true.
Comment: Thanks, @adi. Can this be thought of as an identifiability problem different from the one typically discussed when talking about GMMs? That is, not only can we switch the labels of the data points around, but EM can also converge "early" if one of the cluster means collapses onto a point. This is because, the likelihood would go to infinity, causing the algorithm to converge. Depending on which mean collapses onto which point and how soon (in terms of EM iterations) convergence is reached (both of which depend on initialization), there could be many models with infinite likelihood.
Comment: @CliffAB I reworded my answer. I suppose you should call a configuration of parameters as a solution only if they are at an optima(?)
Comment: Yep! I was just worried that your previous answer could have been misinterpreted.
Comment: @CliffAB, why can't you consider a degenerate solution as converged?
Comment: Because when the EM-algorithm is approaching it, the difference in log likelihood at each iteration will not approach 0.
Answer: In such a case (like many others : HMM, ME) you should be careful to use a logistic representation of you likelyhoods, ie store log(v) instead of v for a value v. The important point is to avoid floating point underflow/overflow.
Comment: This answer seems to not related to the question - the question is not about numerical stability, but rather any theoretical reasons/scenarios where ML will not find a solution.
Comment: "Logistic" does not mean "logarithmic," although the latter appears to be the intended term in this answer.
Comment: Thanks, @mbl. Are you suggesting that the issues are only computational and not theoretical?


Triggering hoverIntent in a Capybara/Selenium test

Question: Has anyone figured out how to trigger a hoverIntent event via Capybara?
In my Rails app's main view, edit buttons appear in a table cell when the user hovers the mouse over that cell.
I recently added the jQuery hoverIntent plug-in to delay the appearance of these buttons, so that the UI doesn't look like a busy switchboard when the user moves the mouse quickly across the page.
The addition of hoverIntent broke several Cucumber-Capybara-Selenium tests, unfortunately. The tests had been making the buttons appear with a step like this (simplified):
<code>And /^I hover on the table cell with ID "(.*)"$/ do |cell_id|
  selector = "td#" + cell_id
  js = %Q{ (function() { jQuery("#{ selector }").mouseover(); })() }
  page.evaluate_script js
end
</code>
This worked well for the regular mouseover event, but it doesn't trigger hoverIntent.
One (kind-of-hackish) solution would be to create named functions to pass to hoverIntent for the mouseover and mouseout behaviors (instead of anonymous, inline functions as I'm doing now). The Capybara step could then invoke the mouseover function by name, and get the same result.
This would side-step the testing of the hoverIntent functionality, though, so it isn't optimal.
Thanks in advance for any suggestions.
Answer: For the hoverIntent to register I believe the browser needs to sleep for the duration of your hoverIntent delay.


In house vs home visits

Question: When do we use in house acupuncture, and home visit acupuncture in a situation where  organisation works within itself and only for that organisation? But at the same time does house calls?
Answer: This is rather a quirky aspect of English and might seem rather strange to foreign speakers.

In-house acupuncture

This means that acupuncture is done on-site.  This does not have anything to do with visiting other people's homes.

Home-visit/house-visit acupuncture
In-Home Acupuncture
Acupuncture done by House-calls

These mean you visit someone's house and do acupuncture.  The latter two sound the least awkward of the three to me.
Comment: If you worked for a complementary therapy centre which had partners and employees who were acupuncturists but also used free-lance contractors sometimes then treatments given by partners or employees would be in-house treatments and those given by contractors would be contract treatments. Whether the treatments were given at the centre, in the client's home or at some other location would not matter in this respect.
Answer: "In house" tends to be used to refer to a product or service which could potentially have been made by a third party but was instead made by you/your business. E.g.

Our marketing team uses our own in-house software

or

Come buy our ovens, all parts are made in-house.

In your case, you definitely want to go with "Home Vist".

In house vs home visits


Text-based file navigator with search as you type

Question: How do I set up Midnight Commander or other text-based file navigator so that when I start typing it searches the first directory or file matching the typed text?
Answer: I presume you mean "search for", not "search in".
If you want to use tab autocompletion with mc on the command line, use alt-tab (or ctrl-alt-tab if that doesn't work) instead of tab.
If you press ctrl-s, you'll see a highlighted search bar replace the "mini-status" bar at the bottom of your current panel.  When you start typing, the selection bar will jump to the first matching file name (so, e.g., you can just hit 'm' to go to files starting with m).  Esc closes the bar.
Comment: uu, nice. How do I make Ctrl-S always-on?


Meromorphic functions of several variables

Question: Is there a concept of meromorphic function of several complex variables? Is there a Taylor series description of such a function? More specifically, I am wondering if such several variable meromorphic functions should have poles only at isolated points, or they can have larger sets as poles? As an example, consider functions of two complex variables $z_1, z_2$. Is $f(z_1, z_2) = \frac{1}{z_1 - a_1}, a_1 \in \mathbb{C}$ a meromorphic function? What about the function$g(z_1, z_2) = \frac{1}{(z_1 - a_1)(z_2 - a_2)}, a_2 \in \mathbb{C}$? Thanks in advance!
Answer: A function $f$ of several complex variables is called meromorphic on $\Omega$ if for every $a \in \Omega$, there is a neighbourhood $U \ni a$ and holomorphic functions $p$ and $q$, where $q$ is not identically $0$, on $U$ such that
$$
f(z) = \frac{p(z)}{q(z)} \qquad \text{for } z \in U \setminus q^{-1}(0).
$$
In particular, the quotient of two holomorphic functions on $\Omega$ is meromorphic, so both your examples are meromorphic.
Note some differences with the one-variable case:

The singularity set of a meromorphic function is never discrete or even compact. In fact, it's an analytic variety of codimension $1$. (Hartogs' extension theorem shows that if $f$ is holomorphic on $\Omega \setminus K$ where $K$ is a compact subset of $\Omega$, then $f$ admits a unique extension to a holomorphic function on $\Omega$.)
We can't "extend" $f$ to its singularity set by pretending that $f=\infty$ there. For example look at $f(z,w) = z/w$ and see what happens as we approach the origin along various paths.
Comment: Not necessarily. For a simple counterexample, take
$$S = \bigcup_{j=1}^\infty \{ z : |z| = j \}.$$
The singularity set of any meromorphic function (that is not entire) will intersect $S$. If $S$ is also compact, then yes: $1/(\text{suitably chosen first degree polynomial})$ will do.
Comment: One quick question if I may (I am trying to better understand the singularity set of the meromorphic function). Suppose $S \subset \mathbb{C}^n$ is a closed set whose complement is unbounded. Can I construct a meromorphic function whose singularity set avoids $S$ and the function is bounded on $S$ (in dimension $1$, such things are easily achievable)?
Comment: Do you require that $K$ has codimension $\geq 2$?


How can I troubleshoot faulty motion-sensor security lights on a timer?

Question: I have around 5 security lights with motion sensor around the house but they are not working, and I couldn't figure out where the switches are. Finally, in the garage I found this timer (attached). I can't think of any other thing in the house can be the switch for the security light, but it seems damaged, because the odds of 5 security lights go bad should be very low. So I guess my first question is, is this thing typically used as switch for security light? If so, what is the best way to troubleshoot this?
Comment: Yes, that type of timer was fairly common for security lights before light and motion sensors became commonly available. If you want troubleshooting help you'll need to revise your question with more detail. There's not enough to go on as it is.
Comment: You can jumper around the time. You should anyway; you don't want to EVER sever power to a motion sensor, because it has RAM memory in it... it remembers what the  brightest and darkest times are, so it calibrates for day/night in that location.  Motion sensors already have light sensors so they don't turn on in the day.
Comment: And the odds of 5 security lights going out over time without anyone noticing are good. Are you sure they were _all_ working recently? Could be the last one or two went out before you noticed the problem.
Comment: Good to know that odds is actually not as low as I thought.. Actually I don't know when it stopped working, it is possible that the previous owner also don't know..
Answer: This is a very common type timer for light, sprinkler pumps, pool filters, etc. Start out by pulling out the yellow disk and turn it to the current time. Monitor it to see if it keeps proper time. There is an "off" tab still on the disk but no "on" tab. It looks like it might have fallen off and is still in the box. This would prevent the lights from going on. There is also a silver lever that says "on" and "off". This lever is a manual switch for anything hooked up to it and it will over ride the timer so start checking that to see if the lights go on. Then turn off the power and swing that plastic cover out of the way and check the wiring for power. Also check the bulbs to make sure they are good.
Comment: @diabloooo0  If you mark and remove the wires, after turning off the power,    the insides come out by  lifting that clip on the upper left of the box. Intermatic  sells those motors separately at many home stores. Might save you some time.
Comment: @diabloooo0 It depends on the load. Mechanical ones are good for larger loads and motors and are good for outdoors. The one you picked at HD will work if load is under 15 amps. You might need to install junction box depending on what's behind the existing timer.
Comment: @diabloooo0  You've got 1800 watts to play with... stick with LED and you'll have more than enough.
Comment: Thanks. I just went to turn the silver lever to on and nothing seems to be working. Also the picture was taken yesterday and when I check today it is in same position, but I do still hear the ticking sounds inside... So it seems for sure this timer needs a replacement?
Comment: Will try it. Any suggestion/recommendation about an easy replacement with some kind of digital display or maybe even "smarter" device?
Comment: I also found on internet there are digital timers like this https://www.homedepot.com/p/Intermatic-Ascend-Standard-15-Amp-7-Day-Indoor-Programmable-In-Wall-Timer-with-Auto-DST-and-Astro-ON-OFF-in-White-ST700W/304600961, these seems pretty much around same price as the mechanical one in my post, is there any reason that people still choose the mechanical one?
Comment: Thanks Jack. I have around 5 or 6 motion security light (will need to replace though), and probably 7 or 8 landscape lighting, pretty much all I can see so far. I guess I should be good to go with the digital one?
Answer: Just so you know Motion sensor lights do have a finite amount of life before they expire. Depending on the brand a motion sensor can be expected to last anywhere's from a few months to several years. The latest LED models have longer bulb life, but it's usually the motion sensor that expires first.
Pull one of them from the round box and check for power with a voltage tester. This is the surest way to know if the light is supposed to be working.
Also, unless you know otherwise, most motion sensors are commonly controlled by a toggle switch located on the interior of the house by a door leading outside.
Comment: Thanks for the info! Much appreciated. Assuming it is the sensor that went bad, I would guess it is probably not worth it by just changing the sensor? Any recommendation on a good motion sensor security light that last longer?


How to list all Git tags?

Question: In my repository, I have created tags using the following commands.
git tag v1.0.0 -m 'finally a stable release'
git tag v2.0.0 -m 'oops, there was still a major bug!'

How do you list all the tags in the repository?
Comment: Related, and even more useful: [show all tags in git log](https://stackoverflow.com/q/4211604/4561887)
Answer: git tag

should be enough.  See git tag man page

You also have:
git tag -l <pattern>

List tags with names that match the given pattern (or all if no pattern is given).
Typing "git tag" without arguments, also lists all tags.

More recently ("How to sort git tags?", for Git 2.0+)
git tag --sort=<type>

Sort in a specific order.
Supported type is:

"refname" (lexicographic order),
"version:refname" or "v:refname" (tag names are treated as versions).

Prepend "-" to reverse sort order.

That lists both:

annotated tags: full objects stored in the Git database. They're checksummed; contain the tagger name, e-mail, and date; have a tagging message; and can be signed and verified with GNU Privacy Guard (GPG).
lightweight tags: simple pointer to an existing commit

Note: the git ready article on tagging disapproves of lightweight tag.

Without arguments, git tag creates a "lightweight" tag that is basically a branch that never moves.
Lightweight tags are still useful though, perhaps for marking a known good (or bad) version, or a bunch of commits you may need to use in the future.
Nevertheless, you probably don't want to push these kinds of tags.
Normally, you want to at least pass the -a option to create an unsigned tag, or sign the tag with your GPG key via the -s or -u  options.

That being said, Charles Bailey points out that a 'git tag -m "..."' actually implies a proper (unsigned annotated) tag (option '-a'), and not a lightweight one. So you are good with your initial command.

This differs from:
git show-ref --tags -d

Which lists tags with their commits (see "Git Tag list, display commit sha1 hashes").
Note the -d in order to dereference the annotated tag object (which have their own commit SHA1) and display the actual tagged commit.
Similarly, git show --name-only <aTag> would list the tag and associated commit.
Note: use Git 2.37 with git show-ref --heads/--tags.

Hi-Angel adds in the comments:

"listing tags starting with tag α":
git tag --sort=-creatordate --contains α

Comment: It's probably worth adding that -m or -F implies -a (if non of -a, -s or -u are supplied explicitly. You can't have a tag message without creating a 'proper' tag object.
Comment: @Hi-Angel Good point. I have included your comment in the answer for more visibility.
Comment: Worth also adding "listing tags starting with tag α": `git tag --sort=-creatordate --contains α`.
Answer: To list tags I prefer:
git tag -n

The -n flag displays the first line of the annotation message along with the tag, or the first commit message line if the tag is not annotated.
You can also do git tag -n5 to show the first 5 lines of the annotation.
Comment: This was the solution I searched to list tags with their descriptions. Thanks a lot..
Answer: And here is how you find the remote tags:
git ls-remote --tags origin
Comment: Exactly what I've been looking for! Thank you. Also, is there a way to fetch only tag names, since this command shows you a full dump of SHA and ref strings with tags?
Comment: `git ls-remote --tags origin | grep -Eo 'v[0-9.]+$'`
Answer: Also git show-ref is rather useful, so that you can directly associate tags with correspondent commits:
$ git tag
osgeolive-6.5
v8.0
...

$ git show-ref --tags
e7e66977c1f34be5627a268adb4b9b3d59700e40 refs/tags/osgeolive-6.5
8f27e65bddd7d4b8515ce620fb485fdd78fcdf89 refs/tags/v8.0
...

Comment: Being used to Mercurial's `hg tags` I like that `git show-ref` gives me the tag AND the revision.
Answer: Listing the available tags in Git is straightforward. Just type git tag (with optional -l or --list).
$ git tag
v5.5
v6.5

You can also search for tags that match a particular pattern.
$ git tag -l "v1.8.5*"
v1.8.5
v1.8.5-rc0
v1.8.5-rc1
v1.8.5-rc2

Getting latest tag on git repository
The command finds the most recent tag that is reachable from a commit. If the tag points to the commit, then only the tag is shown. Otherwise, it suffixes the tag name with the number of additional commits on top of the tagged object and the abbreviated object name of the most recent commit.
git describe

With --abbrev set to 0, the command can be used to find the closest tagname without any suffix:
git describe --abbrev=0

Other examples:
git describe --abbrev=0 --tags # gets tag from current branch
git describe --tags `git rev-list --tags --max-count=1` # gets tags across all branches, not just the current branch

How to prune local git tags that don't exist on remote
To put it simple, if you are trying to do something like git fetch -p -t, it will not work starting with git version 1.9.4.
However, there is a simple workaround that still works in latest versions:
git tag -l | xargs git tag -d  # remove all local tags
git fetch -t                   # fetch remote tags

Comment: The *rev-list* related command gave me a list, but ended in an error: `v0.1.0-rc1
fatal: No tags can describe '5db7534...4a94'.
Try --always, or create some tags.`
Answer: Try to make git tag it should be enough if not try to make git fetch then git tag.
Comment: I think what he means is this:
Running `git tag` command should be enough if you just want to see a list of available tags. If you can't see some tags that you believe may exist on remote, then your local tags may not be in sync with remote. In this case, fetch the latest refs/heads from remote first `git fetch`, followed by the actual `git tag`.

I usually run a one-liner like this: `$ git fetch -p && git tag`just to be sure I am looking at latest and greatest.
Answer: To see details about the latest available tag I sometimes use:
git show `git describe` --pretty=fuller

Answer: You can list all existing tags git tag or you could filter the list with git tag -l 'v1.1.*', where * acts as a wildcard. It will return a list of tags marked with v1.1.
You will notice that when you call git tag you do not get to see the contents of your annotations. To preview them you must add -n to your command: git tag -n2.
$ git tag -l -n2

v1.0            Release version 1.0
v1.1            Release version 1.1
The command lists all existing tags with maximum 3 lines of their tag message. By default -n only shows the first line. For more info be sure to check this tag related article as well.
Answer: If you want to check you tag name locally, you have to go to the path where you have created tag(local path).
Means where you have put your objects.
Then type command:
git show --name-only <tagname>

It will show all the objects under that tag name.
I am working in Teradata and object means view, table etc
Answer: Because the following two commands result in the same order and list length, here's a one shot example from bash:
paste <(git tag -l) <(git tag -l | xargs -n1 git rev-parse)

Answer: For a GUI to do this I have just found that 'gitk' supports named views.
The views have several options for selecting commits.  One handy one is a box for
selecting "All tags".
That seems to work for me to see the tags.

How to list all Git tags?


How would you describe the technique/etiquette or "do's and don'ts" of having a conversation?

Question: I'm trying to find a good word to describe "things to do" while having a conversation with someone. For example, you would want to make eye contact, affirm your speaker, and not check emails on your smart phone. These simple examples, to me, appear like etiquette. However I feel that word etiquette is really only used for "good or acceptable" manners. If I were to add conversation techniques, tips, or tricks, then I feel that I'm outside the scope of etiquette, and really need a word that combines the two together.
Comment: "Conventions" describe social norms - whether polite or impolite. This may be what you're looking for.
Answer: Try rules of conduct or protocol. Though do's and dont's is the best usage.
Comment: Excellent specific answer to the question.
Answer: Perhaps "Conversation Pointers". I think that could cover both etiquette and technique.
Answer: I think that what you are referring may be commonly described as 'good manners', but more specifically to body language and the so called behavioural techniques on which a lot of scientific literature exists. In the specific case they refer to the right attitude and behaviour to take during a conversation to avoid annoying your counterpart ( reading mail while speaking) and be most effective in what you have to say (making eye contact for instance).
Answer: Another possibly useful term (from the field of professional counseling) is attending behavior, which consists of all of those things you do to convey that you are listening and actively engaged with the conversation. Attending behavior covers much of the receiving side of the conversational exchange, including eye contact, giving verbal feedback that you are following the speaker's discourse, not interrupting, etc. There are also rules for turn-taking,sticking with or changing subjects, and probably other facets of conversational exchange.
What is ATTENDING BEHAVIOR?
any behavior engaged in while attentively listening. For example, exhibiting an open, interested posture, maintaining eye contact, and using an interested expression. Proper attending behaviors, along with active listening skills, are considered cornerstones of a therapist
http://psychologydictionary.org/attending-behavior/
Psychology Dictionary: What is ATTENDING BEHAVIOR? definition of ATTENDING BEHAVIOR (Psychology Dictionary)
Answer: Try the simple

the do's of good conversation.
Comment: I don't understand your objection. I am inviting the OP to reconsider one of the terms they used in the title, suitably reframed, because it appears to me to be the best solution to the problem they are trying to solve. In what sense does this "not provide an answer to the question"?
Comment: This does not provide an answer to the question. To critique or request clarification from an author, leave a comment below their post.
Comment: @RyeɃreḁd - I forgot to add a tag to my response to you, which perhaps explains why you haven't yet explained your objection. However, I'd still be grateful for your clarification.
Comment: Erik - I didn't downvote but how it was originally was more of a comment and it still kind of is.  I don't know if the OP understands why you think this and I thought I would save you a few points from a downvote you already had.


My posset curdled, is it salvageable?

Question: Today I tried my 1st posset.  Everything was going good until I added the lemon juice.  It immediately curdled?  Is there anything I can do to save it?
Comment: The wikipedia definition of a Posset: "British hot drink of milk curdled with wine or ale". So curdle it did.
Comment: @rackandboneman I am not British, so I am not sure how contemporary posset is consumed, but I suspect people might be trying to make uncurdled versions, more like a vla with or without dairy, but with the addition of acid - which of course makes the custard much more finicky. Still, I don't think we can hazard an answer without a recipe.
Comment: Can you please include the recipe that you've used? It's sort of difficult to tell you what went wrong if we don't know what you've added to it.
Answer: Assuming that you are making a modern yolkless posset like this one: https://www.cooksillustrated.com/articles/173-introducing-lemon-posset
This kind of recipe is very dependent on the ingredients ratio and the acidity. You have to pick a recipe which has sufficient fat (and you cannot substitute anything - use real dairy cream, not any kind of nut milk) and sufficient sugar to withstand the curdling. Also, you cannot have too much acidity - so pick a ripe lemon, and be sure to measure properly. If you have either not enough buffers (fat and sugar) or happen to have an extraordinarily sour lemon, you will get curdling.
The recipe I linked also suggests partly evaporating the cream, which will be further help against curdling, but it should work without it too.
It is impossible to change anything about the curdled dessert. You can either choose to enjoy it as it is (try thinking of it as a dessert on a tvorog basis) or toss it. You can also try dressing it up (add fruit or marmalade) or incorporating it somewhere (e.g. add rum raisins and use as strudel filling) but you will not get rid of the texture, so if you hate it, be aware you might waste more ingredients and still not like the result enough to eat it.

My posset curdled, is it salvageable?


What is the best slideshow to CCK image field?

Question: I would like to know your suggestions about the best slideshow module to images uploaded from CCK image field. When I mean best, I want to say quality/quantity of features supported according your experience, but if you know another criteria (like support), please feel free to give your suggestion according your criteria.
Comment: I agree that this is a valid question, but as it is written, it is best for forums on D.O, rather than Q/A on DSE. Better to specify what you need in one, rather than a wiki-style comparison that creates a lot of discussion (much like this one now).
Comment: plese feel free to warn about possible duplicate question. I can not find recomendations in 'Search results' or 'Similar Question' list.
Comment: to avoid having ur question closed, as this is more opinion than fact. can you elaborate on ur question to isolate the features you are looking for in particular?
Comment: thank you for your warn. yes I want to find opinions, due that the human brain can, like you know (additionally to answer, according facts) can answer specific information using incomplete(and/or)vague(and/or)relative(and/or)generalistic information. ¿and why here? this is the best place to know experiences of people interacting with Drupal.

to avoid closed my question, I will edit it to be more specific.
Comment: Nigel, thanks for your time to talk me about a good practice to make questions in DSE, I am newbie in DSE, and also in this model of Q/A sites. Can you tell me what is the meaning of D.O?
Comment: D.O. stands for drupal.org
Comment: If is possible I will wait one day to know if exist some answers. this is possible? or do you recommend delete my question?. I can delete if you ask. like I say, I am newbie in this Q/A model.
Comment: See what happens. :) I have answers to give, but the question is too vague for me to determine which one would best suit your situation. Personally, most module choices are not dictated by the overall features, but rather the use-case, especially in the case of photo/slideshow/gallery
Answer: Well, there is of course this page in the drupal docs: http://drupal.org/node/418616
Unless you have a very specific use case which can be accommodated by a specialized module you really should go with the views slideshow module (http://drupal.org/project/views_slideshow). Very well maintained, fairly well documented (but a lot of tutorials flying around) and a lot of modules integrating with it. With this module you can do almost everything slideshow-wise but it might be a bit complicated (but again: lots of tutorials available).
You can of course check out some of the other modules if they offer something more matching to your specific needs.
Comment: very useful resource!
Comment: dddave thanks for your recomendations, is a interesting list, plenty of descriptions and criterias.


Will using snapseed make the quality of my photos worse?

Question: I often like using simple editing software on my iPad, however if I were to shoot in RAW and then export a photo as a png/jpeg and then saving it on snapseed, would using the program make the resolution worse?
Comment: Presumably you mean editing and resaving in [Snapseed](https://itunes.apple.com/us/app/snapseed/id439438619), right? (Not just _opening_....)
Answer: So, the short answer if you're editing and saving from Snapseed is yes. There are a couple of reasons why this will result in reduction of quality:

You've discarded data from RAW to PNG/JPG in the first place. This now gives less information for Snapseed to work with and so further edits could result in even less data, especially in the shadows and highlights for subsequent saves.
JPG is already a lossy format and subsequent saves result in even more loss from the original compression. Ideally, to maximize JPG quality, you want to always start from the RAW data. Now PNG isn't inherently lossy, but see point 1 and then your choice of subsequent output formats from Snapseed will matter as, if I recall correctly, it converts to compressed JPG on output.

In any event, for web display and usage, I'd be surprised if any would really be able to tell. If you're looking to print large (e.g. greater than 8x10) then I would avoid this workflow altogether, but for small usage, I suspect you would struggle to see the effects unless your JPEG compression was really strong.
Answer: The answer is definitely YES but if this iPhone use only then it probably doesn't really matter as the destruction of your image is part of the aesthetic of SNAPSEED.
NIK Filters make a sharpening plugin and a Analogue FX plugin for photoshop that you can use with 16bit images - as NIK make SNAPSEED then that's the direction you could go


Total power output a generator is able to produce

Question: I have an oversized generator, it has 150 kVA and I am only using 25 kW. If the power factor is determined by the load, how can I determine the total surplus of energy that I could generate if I would for example sell that surplus?
Comment: Does this answer your question? [Electric generator fuel consumption while load is increased](https://electronics.stackexchange.com/questions/590300/electric-generator-fuel-consumption-while-load-is-increased)
Comment: Hi! Welcome here! What have you been able to figure out so far? You seem to know what a power factor is, which actually kind of means you know how to answer this, so I wonder how we can help your understanding, instead of doing this small math exercise for you?
Comment: @TFM, this question is very simmilar to your last question, can you delete one and edit the question that you want to keep?
Comment: 1. What is the power factor of your current load ...is it truly 25kW unity power factor or it is something else? Typically the generator rating is some specified kVA at a fixed power factor eg. 150kVA @0.9..   2. Selling power back to the utility is normally at unity power factor.
Answer: You are confusing the concept of power factor with efficiency.

power factor is the the ratio of real power (kW) to 'apparent' power (kVA), computed as kW/kVA.
efficiency is the ratio of energy out (real watthours) to energy in (liters of fuel * joules/l).

'Apparent' power, kVA, is the vector sum of real and reactive power.
More here: https://www.electronics-tutorials.ws/accircuits/power-triangle.html
Ultimately, the genset engine is supplying real power only, that is consumed (does work) in the load and as heat losses in the alternator. The reactive power component circulates in the alternator but otherwise does no work. Nonetheless, the alternator is sized in kVA to account for that, even though that reactive component doesn't load the engine significantly.
See also: What does a power factor of a generator means?
Your genset should have a curve showing efficiency (or at least fuel consumption) vs. output power. There will likely be a 'sweet spot' starting from the mid-range that will be maximum efficiency.
That said, a genset of this size won't be as economical as a large scale utility. It is unlikely that you'd come out even selling your genset's 'excess' capacity back to the grid. Solar or wind are a different story.
Comment: "power factor is the the ratio of real power to (reactive + real)" // No, the denominator is not real power + reactive power. It's apparent power, which is the square root of the sum of the square of real power and reactive power.


What does maximizing mutual information do?

Question: In information theory, there is something called the maximum entropy principle. Are other information measures, such as mutual information, also commonly maximized? If mutual information describes the reduction in uncertainty of characterizing one random variable (r.v. 1) based on full knowledge of a second random variable (r.v. 2), then would maximizing mutual information mean knowing everything about r.v. 2 will allow us to also have full knowledge of r.v. 1?
Answer: Just to give one example in machine learning context, for unsupervised learning, maximizing $I(X, Y)$ can build good representations $Y$ of input $X$, see here and here
Comment: Mutual information is a measure of the amount of information one variable reveals about another where 0 indicates independence, larger values indicate stronger dependence. It always helps to go back to the source, in this case, Gelfand and Yaglom, *Calculation of amount of information about a random function contained in another such function*, American Mathematical Society Translations, 1957, Series 2. 12: 199–246. Also, there's this thread..https://stats.stackexchange.com/questions/81659/mutual-information-versus-correlation
Comment: Being able to pick up nonlinear correlation is nice, isn't it? However, maximum of MI is hard to obtain due to the joint probability term, so the linked papers are maximizing its lower bound instead in practice. So practically, it is hard to fully recover $X$ from $Y$.
Comment: @doubllle can you describe what the maximization of mutual information accomplishes for the two attached papers in your answer?
Comment: @develarist will do that later
Comment: yeah, I totally agree, and my answer isn't a proper one and needs refinement. I just wanted to quickly comment on what maximizing MI can do. @MikeHunter
Comment: what is the lower bound of MI? the Gelfand and Yaglom paper was not found as pdf
Comment: if elements in the **mutual information matrix** are nothing more than measures of dependence between variables in a multivariate dataset, similar to the correlation matrix, than how does maximizing the mutual information matrix differ from maximizing the correlation matrix? Is it simply able to pick out non-linear dependencies that the correlation matrix can't?


Foreign motorcycle licence in Costa Rica at 16

Question: I heard that in Costa Rica, if you are 16 and have a foreign licence, that you can legally drive a 100cc motorcycle. Is this true?
Answer: This official website states:

Todo Conductor (Costarricense o extranjero) podrá conducir los mismos vehículos que autoriza su licencia extranjero por un plazo de hasta tres meses contando a partir de su ultima entrada a territorio nacional. Durante este plazo NO se homologaran licencias.

Which roughly translates as:

Every driver (from Costa Rica or foreigner) can drive the vehicles authorized by his foreign license up to a period of three months counting since his last entry to national territory. During this time licenses will not be certified.

So in principle it seems that you could if you're staying for less than three months. If you're planning to stay longer you would need to certify you license.
Comment: So the answer is yes if and only if your current licence allows you to drive 100cc motorcycles.


"Have to split" in the film "The Running Man"

Question: In the film The Running Man (1987), Arnold Schwarzenegger cut a man into two halves. His name was Buzz Saw. Then another man said: "Where did Buzz Saw go?" And Arnold Schwarzenegger said: "He had to split." In the cinema people laughed to hear this, but I don't understand why.
Comment: It's a pun on the word "split".
Comment: It's hard to explain puns to kleptomaniacs because they're always taking things, literally.
Comment: Just in case others are misled: this is a joke/troll account that asks silly and deliberately disingenuous questions that nonetheless require a bit of lateral thinking to locate the actual jokes.
Comment: If he didn't recognize the pun immediately, telling him it's a pun isn't likely to help him -- he presumably doesn't know the slang meaning of _split_.
Answer: It's a pun on the word "split", vs. the idiom "to split". In English, a common, informal expression is "having to split" for "having to leave". (This comes from leaving a group of people being effectively the same as splitting off from them.)
The verb split itself, of course, can mean to be literally split into two halves.
In this case, we had a pun because the man (Buzz Saw) was split into halves. Another man asks where Buzz Saw went (implying that Buzz Saw is absent at this point, i.e. has left). Schwarzenegger says that Buzz Saw has left (he had to split). Unbeknownst to the asker, however, Schwarzenegger also literally split Buzz Saw in two.
Comment: Obligatory: http://i.stack.imgur.com/eHl71.jpg
Comment: Thank you Mr/Mrs Newb! Now I can enjoy to watch the film every way - the graet acting, fiting and also funy things!
Comment: +1 for "unbeknownst"... I have to use that more often.


When importing stl models for 3d printing the pieces are all scattered, Is there a way to re assemble everything?

Question:
This is the result of the imported model. Is the software? Or it comes this way and there is no other solution than manually fixing? Thanks a lot!
Answer: I'm afraid there is no other solution than manually fixing it.
It looks like a 3d printing model, and the parts are designed to be printed separately then assembled (it even look like an articulated model). Maybe try to contact the author, they probably have an "assembled" version of the file.


Connection Pooling vs Per-Thread JDBC Connection

Question: Which of these approaches is better: connection pooling or per-thread JDBC connections?
Answer: Connection Pooling for sure and almost always.
Creating new database connection is very costly for performance. And different DB engines (depending on licensing or just settings) has different maximum number of connections (sometimes it even 1, usually not more then 50).
The only reason to use Per-Thread connections is if you know that there are certain small number of persistent threads (10 for example). I can't imagine this situation in real world.
Answer: Definitely connection pooling. Absolutely no reason to create a new connection for each thread. But, it might make sense to use the same connection for an entire HTTP request for example (especially if you need transactions).
You can easily configure the connection pooling framework to have a min and max number of connections depending on the database that you are using. But before going too high with the max number of connections, try using caching if you have performance issues.
Answer: For web apps, connection pooling is generally the right answer for reasons other have already offered.
For most desktop apps running against a database, a connection pool is no good since you need only one connection and having multiple connections consumes resources on the DB server. (Multiply that by the number of users.) Here the choice is between a single persistent connection or else just create the connection on demand. The first leads to faster queries since you don't have the overhead of building up and tearing down the connection. The second is slower but also less demanding on the DB server.


SVC service page on production

Question: I am testing web service on production.
There is a standard SVC web page available like the example below (another randomly selected webpage, just for example). Is it ok to have this page available on the production environment?
Comment: Is the page needed? If not, do not make it available. Most likely it is not needed.
Answer: The Web Services Definition Language (WSDL) provides all details necessary for binding to the service and is considered an information disclosure finding when the target of a pen test. While the following is dated, they still hold true today.
The following was taken from a Black Hat Europe 2007.

WSDL Enumeration
As with any other web application attack, the first step in formulating an attack on a web service is discovery and fingerprinting of the service deployment. The information gathered at this first stage is crucial to identifying possible entry points and carrying out an attack that is directed at the heart of the web service.
Luckily for today's hackers, web services are often deployed with what many refer to as a 'blueprint for attack'. The WSDL file is a web services deployment descriptor that outlines not only the functionality provided by the web service, but also the expected syntax, the input and output points, and the location to access the service. In other words, the web service is announcing to the world its location, the methods it provides and assumptions it is making regarding its input points -- a goldmine for anyone with malicious intent.
Source: Web Services Vulnerabilities by Nishchal Bhalla and Sahba Kazerooni (published February 15, 2007)

This snippet was taken from OWASP Europe Conference, Leuven, Belgium, May 30-31, 2006.

WSDL and Access Scanning
A WSDL document contains information pertaining to the Web service such as available operations, the content of the messages each of these operations accept and return, and the endpoints that are available to invoke the operations. Securing a Web service should rely on cryptographic measures to fully protect information rather than obscurity (security by obscurity should be avoided), because the information that a WSDL provides can expose certain architectural aspects about the Web service that could make it easier for an unauthorized user to mount an attack.
For example, attackers can determine valid request formats by examining the schemas and message descriptions in the WSDL that can contain operations such as getItemByTitle, getItemById, placeOrder, getPendingOrders, etc. Knowing this information, the attacker may be able to guess other possibly hidden operations such as updateItem, and perhaps use this information to place items on sale and then place orders using newly discounted prices. In fact, it is easy for a developer to introduce such vulnerabilities to
  a Web service since WSDLs are mostly generated automatically and contain a full description of the available operations. Developers may later comment out the operation section to hide it the service, but leave related information such as the message descriptions and schema types of these operations intact.
Source: Securing Web Services by Rix Groenboom and Rami Jaamour (published May 30-31, 2006)

The only thing I would add is that public and private services should be handled differently.

Public Service - If the WSDL describes only publicly accessible content and the service is publicly accessible, there's no risk having it remain public.
Private Service - A service requiring authentication/authorization of any kind should have it's WSDL protected in a similar manner.

SVC service page on production


Attacking moves

Question: While playing chess against a computer I am able to analyse what the computer is going to move even at the highest difficulty level but I am not able to place good moves against the computer. Can anyone tell me how can I improve?
Comment: As it is written, this question seems a bit vague to me. For instance, how have you determined that you are unable to find good moves to play? Have you analyzed your games afterwards and found this out, or do you get stuck without seeing how to proceed during the games? Also good would be to post a game of yours so that the community could get a feel for your general level of play.
Comment: Actually yes I analysed some of my games but how can I post a a game means a normal game is very long how can I post it
Comment: @Bitthal Maheshwari  Copy and paste the PGN here.
Answer: I can't give exact tips specifically catered to your gameplay as you have not provided information on how you generally open your games, but here are a few general tips.
1) Develop Bishops and Knights (get them out into a more accesable spot)
2) Control the center 4 squares of the board so that the opponent can't move their peices through the center (use the 2 center pawns and knights)
3) "Connect" pieces so that if one is taken, the square can be retaken. The centeral pieces should be protected by multiple pieces.
4) Castle your king (This is often somewhat overrated, this shouldn't be your immediate priority but should be done soon after controlling the center if possible) A king behind 3 pawns that are max 2 rows ahead is generally a strong defense, I find putting the king and 3 pawns in a diamond formation to be the best  defense.
5) Avoid moving out your queen to early, keep it protected so you can use it more in the end game.
6) Don't create extensive pawn chains, generally try to just use 2 central pawns and then the one diagonal from the queen then use knights and bishops.
Here's a decent trap for beginner players: Move your bishop infront of your knight, wait for an opening and then take out the rook in the opposing corner.
I hope this helps.
Comment: @AntonMenshov it doesn't improve much. That's one of the items for not accepting an edit.

Attacking moves


Does Ubuntu support working with compressed Windows files?

Question: In Windows 10 pro, there is an option "Compress this drive to save disk space". If I were to enable that option, will Ubuntu be able to open the files like normal? And is there any side effect in using it?
Comment: According to [https://jp-andre.pagesperso-orange.fr/compression.html](https://jp-andre.pagesperso-orange.fr/compression.html) yes, ntfs-3g supports all current NTFS compression methods.
Comment: I'm sorry, I am very new to Ubuntu, and I don't understand any of the link all of you have sent. But, let me clarify, if I were to enable that option and window compressed all the files, will Ubuntu be able to open and use that files like normal?
Answer: Yes.
Linux supports transparent compression of NTFS drives.
See:

Is it a good idea to use compressed NTFS filesystem on an external harddisk?

Yes, it is possible to access it from Liunx

NTFS-3G Wikipedia Article

Transparent compression is supported

Discussion on ubuntuforums.org

File system compression is just more of a headache than it's worth.

The New NTFS Linux Driver Updated With Better Compression Handling

with this latest iteration of the NTFS3 patches, the compression support is more full-featured in dealing with file-system compressed files. NTFS supports per-file compression as well as drive-level compression

NTFS3G - Using Transparently Compressed Files

Currently reading compressed files is supported by all ntfs-3g versions. Creating new compressed files, clearing contents, and appending data to existing compressed files are supported since ntfs-2009.11.14.

It seems, that it's quite well-supported and side-effects are the same as in Windows: Depending on what is the bottle-neck on your machine, you may notice lower performance.
If your bottleneck is CPU/RAM you will notice it more, but if your bottleneck is I/O, it theoretically might even improve your performance as less data has to be written.


iMac beeps 3 times repeatedly when trying to boot up from a Mac OS X install DVD

Question: I have another issue with my iMac, the issue is that it beeps 3 times and they repeat when I start up from a Mac OS X install disc. Recently, I inserted a Mac OS X install disc into my computer, and used the Startup Manager to select the install disc and start/boot up from it. After a while at the grey Apple logo screen, the Mac played 3 tones, and then after 5 seconds, the tones played again/repeated, indicating a POSSIBLE hardware issue, and the startup procedure halted. Do you know what three tones, then a five second pause mean on a Mac? Might be an issue with the RAM. Do any of YOU know?
Answer: 3 tones indicate a RAM failure, my recommendation is to remove all the RAM sticks and verify one by one; to identify which one is damaged.
If you need more information check this useful link:
About Mac startup tones
Comment: If one of the RAM sticks is dead, you don't necessarily have a choice...
Comment: Thanks for your answer! For now, I'm not going to tear down my iMac to remove the RAM sticks.
Answer: Anyone might know that this solution would be helpful. Try holding down the C key at startup to start from a bootable CD or DVD.
Comment: Let us know if this is the answer you was looking for ;)
Comment: Eh. My brother has an iMac from early 2009. I tried booting from the DVD, and then, it seemed to work fine.
Comment: The requirement needed to boot from the Mac OS X install disc I have in my house: you need an iMac from 2009.
Comment: I tried "C" on my iMac and it did boot from the CD, but, the same problem occurs again. Too bad!
Comment: Will the Mac boot from the retail DVD my dad brought home? I hope so...


Do all routers have two IP addresses?

Question: I know that a home router have a private IP address and a public IP address, but what about the routers that an ISP uses, do these routers also have two IP addresses?
Comment: Has any answer solved your question? Then please accept it or your question will keep popping up here forever. Please also consider voting for useful answers.
Answer: The number of IP addresses a router is usually significantly more than 2, that said it is very much possible to have routers with only a single address. Theoretically it's possible to have a router with no-ip address at all but this is generally impractical.
Normally each "interface" of the router will have an address, it's also common for the router to have a "loopback" address, which remains active regardless of which interfaces are currently active.
Interface may be a physical interface, but routers nowadays generally support Ethernet VLANs, so one physical interface may carry multiple logical interfaces.
While it is normal practice for each interface to have it's own address it is not strictly necessary. True point to point interfaces have no need for IP addresses at all. For Ethernet interfaces, the picture is more complicated and IP address is needed for arp and some routing platforms will insist that each interface has it's own IP. Others will allow configurations with each router only having a loopback address, for example a quick google found and article describing an unnumbered confirmation with ospf and aruba routers.
I don't have a link handy but I remember a presentation from a metro network operator saying they liked unnumbered interfaces because in addition to saving addresses they made it much easier to add and remove devices from a ring, and even to deploy optical bypass switches to restore the ring in the event of power failure.
Comment: Interesting HP(Comware) "hack"... define an arp entry from lldp. Of course, the router still has an address, albeit a single one one a loopback that's pseudo-shared with other interfaces. As was debated in the dup of thise question (I smell homework), not all routers have knobs for such nonstandard tweaks. (there are many reasons/benefits to having an address on every interface.)
Answer: Yes and no.
A router's function is to forward between multiple networks or links. Each of those links may be connected to an actual multi-host network - then an IP address on the interface is required - or the link may be point-to-point, then no IP address is required.
In extreme, a router is connected using point-to-point links only (think of simple serial lines), then no IP address at all is required.
ISP routers usually connect to multi-host networks, so they'd have at least one IP address per interface and at least two interfaces. They often have (many) more interfaces than just two however.
Answer: The general rule is that a router needs an IP address for EVERY interface on the device.  This is true regardless of whether the interface is physical or logical.  There are sone exceptions to the rule (like IP unnumbered) but you should plan for having each interface of a router to have an IP address with each of those addresses residing in different subnets.

Do all routers have two IP addresses?


Can a process which is completely based on thoery, without any experimental data, can it be patented?

Question: for example, i have developed a process based on literature and all thoeritical factors, can this work be patented or is it necessary to provide along with experimental data as well.
Answer: I am not sure what your process looks like.
Possibility 1 - A theory / presentation of information:
There needs to be some technical part for an invention to be patented.
See for example Article 52 EPC for Europe:

(1) European patents shall be granted for any inventions, in all fields of technology, provided that they are new, involve an inventive step and are susceptible of industrial application.
(2) The following in particular shall not be regarded as inventions within the meaning of paragraph 1:
(a) discoveries, scientific theories and mathematical methods;
(b) aesthetic creations;  null
(c) schemes, rules and methods for performing mental acts, playing games or doing business, and programs for computers;
(d) presentations of information

It could be something including parts of (a) and (d).
Furthermore you can patent something in that direction, but you need at least some technical part. See Article 52 (3):

(3) Paragraph 2 shall exclude the patentability of the subject-matter or activities referred to therein only to the extent to which a European patent application or European patent relates to such subject-matter or activities as such.

And that is where you may be right (although I don't know if I understood the experimental data right), if you add something,  e. g. a device using that theory etc. it could be fine.
That leads us to
Possibility 2 - A technical process that you did not test yet:
The granting of patents does not involve a check if the invention works. For some fields like biotech you may have to provide even material, but unless it's really obvious (like the Perpetuum Mobile) examiners and patent offices will not object if there is no test data provided.
The invention however needs to be possible to be carried out by what is provided / disclosed in the description of the application:
The best way to practice the invention in the patent application e. g. needs to be provided according to the US patent law (35 US Code section 112). This is requested so an inventor cannot keep some essential or advantageous aspect a secret and still get a patent.
In Europe the EPC asks for at least one way of practicing the invention as defined in Article 83 EPC:

Article 83 Disclosure of the invention
The European patent application shall disclose the invention in a manner sufficiently clear and complete for it to be carried out by a person skilled in the art.


Jacobian transformation

Question: I am trying to calculate pillar-wise sensitivity of a fixed coupon bond using par rates (given pillar-wise zero coupon sensitivities). I came across the formula pv01(par) = pv01(zero) * dz/dr, where dz/dr is the rate of change of the zero rates w.r.t the par rates. I am however unable to understand how to use this formula in excel. Any help is appreciated. Thanks.
Answer: As zero rates are usually not observable, people tend to use the sensitivity with respect to par, or coupon, rates. Here, pv01(zero) is a vector, which cen be computed using the pricing formula that is usually expressed in terms of the zero rates. To compute $dz/dr$, you may need to use a finite difference scheme, for example, to shift the par rate $r$, and then re-compute the zero rates.
Comment: The finite difference scheme is very low on precision and I am looking for more than three digit precision. Any idea on how to achieve the same through Jacobian matrix computation in MS Excel? Thanks.
Comment: @GouravPoddar, To have the Jacobian, you need the analytical expressions between $z$ and $r$. Once you have those formulas, then you can do it in Excel.

Jacobian transformation