Magento 2.3.2 Import only images for multiple products

Question: I want to import images for multiple products. I read many questions and I tried the answer but with no luck.
I want to import images from external server. For that I created CSV with sku, base_image, small_image, thumbnail_image column.
The value in all field is like :
htts://external.com/imgae_name
I selected "Product" in Entity Type, Import Behaviour is Add/ Update. I skip Image file directory.
When I click on "check data" button I am getting following error.

Product Type is invalid or not supported in row(s): 1

If I add Product type column then I am getting attribute set error. Can anybody help me on that ?
Even when I import custom attribute I am getting same error. For that I created csv with sku and cost.
Here cost is my product attribute.
Answer: Try setting your Product type as = 'Default' that should stop the error when you click 'check data' when uploading your csv.


Why the pH of xanthan gum in aqueous solution is 7 (neutral) when it has glucuronic and pyruvic acids in its chemical structure?

Question: Since xanthan gum has both glucuronic and pyruvic acids in its chemical structure, it should release $\ce{H+}$ ions upon solvation in an aqueous solution and make it acidic. However, the meausured $\ce{pH}$ is $7$.
Answer: Pyruvic and glucuronic acids are both pretty strong acids (pK's of respectively 2.5 and 3.28) but that does not mean that the polymer of xanthan gum will be. Those protons are still there but they may be more tightly bound in the polymer than in the free acids. To find out try titrating a solution with strong base. Eventually you should start prying some of those protons off and you should see an inflection point. OTOH as there are so many carboxylic protons in the polymer the inflection points would probably smear and not be visible but you should see  some buffering above some pH if my hypothesis is correct.
I should make clear that this is purely speculation on my part but it sounds like an interesting experiment.
Comment: If this is the case (protons are tightly bound in the polymer), does it mean that xanthan gum is not negatively charged (since it does not release protons to become negatively charged)?
Comment: As another comment here points out the answer is no - at least not at netural or acidic pH. Raise the pH and the protons come off  leaving a net negative charge
Answer: Xanthan gum disperses difficultly in water; the dispersion process can be speeded up by raising the pH to about 10-11. This implies that acidic groups on the polymer are not much ionized, but addition of alkali puts a lot of negative charge on the polymer, helping it to unfold.
Measuring pH of gums, goos, slimes and muds is difficult, especially when the concentration of protons or hydroxide is low. The more xanthan gum you put into water, the goopier it gets; 1% is quite goopy. A measurement of 7 could be +/- 0.25 at least.


Looking for a website to essentially proofread my Spanish?

Question: I am looking for a check my work website to ask for feedback. I know that this website is not for check my work questions. Just wondering where it might be a good place to go?
Comment: @Glorfindel thanks for moving the question back here. We had some debates on whether these questions should be here or in Meta. The current approach is [explained in Meta](https://spanish.meta.stackexchange.com/a/2847/1674) after [voting about it](https://spanish.meta.stackexchange.com/q/2740/1674).
Comment: Would it make sense to add another answer to [Resources for Learning Spanish](https://spanish.stackexchange.com/q/23617)? I do realize it can be useful for both learners and native speakers who are less confident about their texts.
Answer: In the website: enclave.rae.es
there is a verification tool to check one's Spanish. As they say: "Verificador --
Permite verificar la corrección de cualquier texto a la luz de criterios ortográficos, gramaticales, léxicos y de estilo."
This tool is under the heading:"taller" and then click on "verificador."
or    enclave.rae.es/taller/verificador
This is a paid site offered by the "Real Academia Española." They offer seven days as a trial period. After that, according to the site, it is 2.5 euros per month (that may be charged all at once for a year--I am not sure).
The site has many aids to help learn Spanish--especially it has academic tools.
I am subscribed to that site -- but I have not used it that much. When I was charged I believe it was on an annual basis. They have an automatic renewal process. I disengaged that. I prefer to renew manually, if I wish to renew. It has many good things to use--but I have not used it to its full potential.
Your question about verifying the correction of one's written Spanish will motivate me to use that site more. I never paid too much attention to the verification tool. But it looks like a very good tool. I tested it again just now, by writing some incorrect Spanish--and it seems to work very well. It corrected the text (or signalled errors), and offers various options for words spelled incorrectly.
In that verification tool it seems that one can also load files up to it--so the text in the file can be verified also.
It impresses me as a very good tool.
Of course Microsoft Word can also check Spanish for correction. The RAE site may go beyond what Word can do. I need to check the RAE site out more--especially the verification tool.
You had a good question. Thank you.
Note: I am a new participant on this site. This is the first question I have commented on. I hope I followed all the rules when I offered a comment on this question.
PS I just tried using the verification site again. From what I can see now--it corrects misspellings well and faulty accentuation--but it doesn't seem to correct style too well--or things that may not make sense, such as mixing up a future verb with a time indicator like "ayer". Maybe more artificial intelligence is needed! I will continue to check it out.
Comment: Hello "wimi",

Thank you for your welcome and your encouraging comment.

I also appreciate the link that you sent my way so that I could review what Enclave RAE offers. Though I have had that service for over a year--I am definitely not using it to its full potential.
Thank you again. Much appreciated.
Ray
PS And thank you for your service in moderating the Spanish Stack Exchange. The Stack Exchange for Spanish is an amazing resource.
Comment: Welcome to the site! This is a good answer. For additional reference, there is also a review of the tools of Enclave RAE [on our Meta](https://spanish.meta.stackexchange.com/q/4344/24236).


Monitoring software and FERPA

Question: I'm in high school. In my school, students are given Chromebooks with the software called GoGuardian automatically installed, as well as Securly. For some background, GoGuardian saves information and screenshots of what a student is seeing on the Chromebook. Every student is required to have this software, and it is monitored often. I am taking an online course that falls under FERPA laws. This course is run by a university and the university insists that my parents are not able to see any information about the course. I don't believe I have signed any documents giving my rights away to allow monitoring, but my parents did sign a document allowing monitoring on the Chromebook. I have read the law and it did seem to say that it is illegal, but as a high school student with no law experience, I would assume my judgement may not be accurate. Is the school monitoring my course and all of the information for my course legal? If this is legal, do I have rights regarding this information that is taken from me? I am willing to give any context that would be required.
Comment: Is this university course part of your high school curriculum? Or is it something you are doing completely separate from HS on your own, and you just happen to want to use the Chromebook for it?
Comment: I completely missed your comment, sorry. This course is offered by a university and I am completing it during school, using a school Chromebook.
Comment: I can't tell if you're concerned with your parents monitoring your uni coursework or the local school district or both.
Comment: I'm fine with my parents monitoring, it's just the school I'm concerned about.
Comment: Leave open - not asking for a specific course of action.
Answer: You're under 18, so you're viewed as a minor under the law, and as such, you can't agree to and sign legally binding contracts. Your parents must sign for you, and you really have no choice in parental guardian-type duties, such as education. It's perfectly legal for them to sign to allow monitoring on the laptop, as a condition of you using it as school property for your education.

Is the school monitoring my course and all of the information for my
  course legal?

Yes. It the school's Chromebook, and you parents agreed to your use of it for educational purposes. If the HS is presenting the university course, they have presumably worked out the FERPA issues, as you are a minor and your parents do have the authority to see your work.

If this is legal, do I have rights regarding this information that is
  taken from me?

Not really. Once you're 18, you can fight the power. Until then, you're a minor.
Comment: Under FERPA I am considered a college student. This means I am sort of 18
Comment: And they absolutely have not worked out FERPA rules, this post is definitely to confirm legalities that they did not confirm themselves. They have not spoken in much conversation with the university in question, and my parents were required to do most of the work with the course set up.
Comment: How do you know "they absolutely have not worked out FERPA rules"? And what exactly did your parents do that was required for the course set up? And you are not "sort of 18"; you're 18 or you're not.
Comment: My parents did the entire course set up, the only reason the school is involved is for billing, which is yet to be set up. This is why I know they didn't figure it out. Also, I'm the second ever student to do this at this school. And I am considered the same as any other college student according to FERPA.
Answer: It is not clear whether you are an eligible student under FERPA regulations. Since you are apparently under 18, the question is whether you are "attending an institution of postsecondary education" – the regulations do not say what it means to "attend" an institution. Regardless of whether you are an eligible student, FERPA regulations only limit disclosure of student records (they are creating records via this monitoring), and there is no limit on the records that they can create. So your permission is not required to create records (regardless of whether you are an eligible student). FERPA limits disclosure, but also guarantees the right of access by the student or the parent – whether the parent has access rights depends on whether the student is legally an "eligible student".
The university might adopt a legal stance to the effect that any person enrolled in a university-sponsored class is "attending" the university, which would mean that they can deny parents access to the records of their children (whereas your high school cannot deny your parents access to those records, until you turn 18). That does not mean that the university's position is legally correct: if your parents want access to your records, they could sue the university and we might get a court ruling about what "attending" means, in the context of FERPA.
So the only practical limit on access to the Chromebook information is that your parents might gain access, if you are found not to be an eligible student. Apparently, the university takes the position that you are, so they would have to sue to get access to that information. There is no limit on the monitoring that can be done.
Comment: I do like this answer, and I would like to confirm that I am an eligible student according to the university offering the course. However, you are saying that FERPA provides minimal protections against schools taking information, and only really protects against parents?

Monitoring software and FERPA


Denavit Hartenberg parameters

Question: Can anybody help figure out HD parameters for the case where two links with a revolute joint are in the same plane, thus that the variable angle is 0, but the twist is not 0. This is a simple drawing. I think that x-axis that is perpendicular to both z-axis, points away and goes through the intercection of z-axis. The link length is 0, the twist is a and the offset is d. Whould it be correct?
Thanks.
Comment: Don't confuse "joint" with the parts that rotate and "link" with the parts attached to that. In terms of a DH manipulator configuration, a link is a single degree-of-freedom that is attached to a previous link through a joint. The first link is attached to some kind of base, but we need not consider that in the model since it is usually fixed in the world. See [this diagram](https://en.wikipedia.org/wiki/Denavit%E2%80%93Hartenberg_parameters#/media/File:Classic-DHparameters.png).
Comment: Your question needs a lot of clarification. Each individual link in a manipulator has its own joint -- so two links have two joints. Do you mean the two links have revolute joints whose axes are parallel? If that is the case then the relevant $\alpha$ transformation should be 0 ("twist angle"?). Meanwhile, $\theta$ is the joint angle and can be any value within the limits of the joint ("variable angle"?). Your drawing has no x-axes or z-axes, so your reference to them is confusing. Also, $d$ and $a$ are themselves DH parameters already, so you shouldn't use them for new dimensions.
Comment: The links lie in the plane of the drawing I would call it xy-plane, but it would be confusing cause it would look like z-axis lies in the xy-plane. The second joint is revolute, but imagine that the first link is welded at a certain angle that differs from the right angle. Thus the axis are not parallel, they intersect at the point where i would put an vertical x-axis. The directions of the joints are represented by the short thik lines at the ends of the links. The third one would be parallel to the second one, but i am asking about the first and second ones.
Comment: If the first "link" is welded and fixed then it is not a link. Are you saying that $\alpha$ is not 0 for the first link? So the joint axes are not parallel? Please replace your diagram with something in 3D that is more clear.
Comment: A link is always welded to a joint, it is a joint that does all DOFs and a link is just attached to it, I said "welded". This configuration lies in the plane of the drawing. If it was the right angle this would be an ordinary revolute joint.
Comment: Thanks for the updated diagram, are those cylinders representing the joint axes?
Answer: You can use dummy transformations when the DH parameterization cannot get you from one axis to the other. Think of it as two succesive DH transformations where the first one does not have a moving joint. It is just there to get to the other joint the the second DH transformation
EDIT:
to complete the answer with reference:
http://petercorke.com/doc/rtb_dh.pdf
If your previous Z axis is not intersecting the next X axis and/or they are not perpendicular, you will not be able to use one DH transformation matrix from one coordiante system to the other
Comment: I dont quite understand what you mean. It is an ordinary revolute joint. If two consecutive joints had the same direction for z-axes, it would be no problem to find the parameters, cause they are parallel and you can get a perpendicular line to both of them. But if those z-axes intersect one another the perpendicular line (x-axis) can be put only like in the drawing. The twist - a rotation from one z-axis to another about x-axis can seem to be found easily - it is represented by a, r-parameter seem to be zero and I am not sure what I would call d in this case.
Comment: The point is this: DH parameters allow you to transform from one joint to another using a common set of rotations and translations (see [this video](https://www.youtube.com/watch?v=rA9tm0gTln8) for clarification). Your particular configuration may need a modified version of DH parameters -- namely a y-component for the link length (usually has only x- and z-components, $a$ and $d$, respectively). This is because the new rotation axis for a joint should rotate about the previous x-axis, but your configuration cannot be defined as such.
Comment: As Brian Lynch pointed out, the DH transformation matrix has only 4 parameters, so you can only do 4 "motions" from one coordinate system to the next one. In your case it seems that with one DH transformation you cannot get from where you are to where you want to be. In these cases, if you still want to use the DH convention, you can use two DH transformations Use the first one just to rotate the coordinate system in the first joint to an orientaion the allows you to use a second DH transofmration to transittion to the desired coordinate system at your joint in queston.
Comment: To Brian Lynch: I saw this video. It deals with the convenient case I can deal with without the video. Is there a formal formulation for this y-parameter and does it mean that HD parameters can not deal with all cases because actually just slitest deviation from a right angle when z-axes are not parallel but lie in the same plane means I can not use the standard HD parameters?
Comment: To 50k4: >>if you still want to use the DH convention.   What would be another set of parameters or another convention that I could use insted?
Comment: Please refer to the asnwers given to this question: http://robotics.stackexchange.com/questions/7763/why-do-we-generally-prefer-dh-parameters-over-other-kinematic-representations-of n also, you can parametrize the robot however you choose. If you get the IK right and you do no t plan to collaborate with anyone used to the DH convention formalism of the parameters does not matter

Denavit Hartenberg parameters


Can I create a will before our baby is born?

Question: We are having a baby and I had a question about creating a will. I am planning on talking to a lawyer before doing so, but just wanted some quick advice. Can I create the will before the baby is born? When I tried to find some will samples online, the forms all asked for the child's name, which we don't have yet. I'd really like to get as much done before the baby is born, for obvious reasons, so is this something I can do, or do I have to have the baby named before I can create the will?
Answer: Yes. Typically, a will is drafted so that it applies not only to any current children but also to afterborn children. In a statement of family, in a Will, I would often say that:

"children" as used in this Will including the following persons and
  any other person subsequently born to me or legally adopted by me.

Then I would draft the guardianship and dispositive provisions using the term "children" without specifying a name.
If children are born, but there might be a paternity issue, it isn't uncommon to state that "my children at the time this Will is executed are . . . . and I intentionally exclude from benefit hereunder or for any fiduciary position with respect to me, any other person claiming to be a child or other descendant of mine as of the time that this Will is executed, but do not intend to exclude subsequent children or children later adopted by me."
Answer: I assume that your actual question is about leaving money to this (currently non-existent) child. There are certainly ways this can be done, such as leaving a sum "to be divided between all my children living at the date of my death", or something "to my second [or whatever] child", but none of them are legally foolproof. Your lawyer will be able to advise you how best to give effect to your wishes, but you need to think in advance what those wishes are, particularly in unpleasant and unlikely cases such as the early death of a person named.


why does TTLV encoding in KMIP require padding?

Question: I study the KMIP in OASIS standard, I need some help.
Integers, Enumerations, and Intervals in KMIP length shall be padded with four bytes. the reason for padding in kmip is need to match the right size??
Answer: The padding in KMIP is present only when data is converted to TTLV format, which is a binary representation of KMIP data. TTLV padding exists to "provide optimal alignment for both 32-bit and 64-bit processors" according to the kmip specification. It's generally easier for a CPU to load memory when it's aligned to certain byte widths, especially when the CPU is doing work in parallel.
see section 9 in the kmip 1.0 spec:
https://docs.oasis-open.org/kmip/spec/v1.0/os/kmip-spec-1.0-os.html#_Toc262581260
wikipedia describes how "there can be substantial performance advantages from using aligned data" on x86 cpus:
https://en.wikipedia.org/wiki/Data_structure_alignment
Comment: Thank you for best answer to me. I also learn about the Data Structure Alignment for you. Thanks
Comment: Dear fafrd, Unfortunately I have a another Question. so.. Would it be possible for you provide me with your E-Mail? please.. Thanks.


Are all U.S. patents that state they were developed with support of a U.S. government grant essentially owned by the U.S?

Question: Near the front of many patents there is a statement saying the work was partially or fully supported by a U.S. Government grant. Does that mean that the U.S. Government automatically owns all that IP?
Answer: No, under the Bayh-Dole act the law was changed to permit the grantee to own the IP but, of course any deliverables under the grant need to be provided to the granting agency. Before 1980 all IP developed with government $ belonged to the U.S. This change was made to spur the economy.
From Wikipedia:

The Bayh–Dole Act or Patent and Trademark Law Amendments Act (Pub. L. 96-517, December 12, 1980) is United States legislation dealing with intellectual property arising from federal government-funded research. Sponsored by two senators, Birch Bayh of Indiana and Bob Dole of Kansas, the Act was adopted in 1980, is codified at 94 Stat. 3015, and in 35 U.S.C. § 200-212,[1] and is implemented by 37 C.F.R. 401.[2]
  The key change made by Bayh-Dole was in ownership of inventions made with federal funding. Before the Bayh–Dole Act, federal research funding contracts and grants obligated inventors (where ever they worked) to assign inventions they made using federal funding to the federal government.[3] Bayh-Dole permits a university, small business, or non-profit institution to elect to pursue ownership of an invention in preference to the government.[4]


Synonymize the tag [tfjs] with the main tag [tensorflow.js]

Question: tfjs should be marked as a duplicate of tensorflow.js.
Comment: Can you explain why this synonym is appropriate?
Comment: This user is the top contributor in these tags by a very long shot.  [tfjs] seems a very good way to get a hold of them though :)
Answer: Hans notes in a comment that, despite the apparent lack of thought behind this proposal, you nevertheless clearly know what you're talking about, being the top user by a large margin for the tensorflow.js tag. (Thanks for your hard work there!)
Also, I reviewed the questions that were tagged tfjs, and it was apparent enough to me (despite my own total lack of familiarity with this technology) that the questions using that tag were all about TensorFlow.js.
Therefore, I have gone ahead and completed the merge:
tensorflow.js ← tfjs
As part of this process, tfjs was removed from 26 questions, and tensorflow.js was added to 12 questions (which were previously tagged only tfjs without tensorflow.js).
Comment: Yeah, the tagging system isn't ideal, but it's the best we've got. Mods can always be reached on Meta for support with making big changes like synonyms, merges, etc. Also, do remember that you have the privileges to retag any questions as you see fit. (Maybe you're already doing this; I haven't checked.)
Comment: Thanks. I should have added more details. Unfortunately being the only top contributors on the tag doesn't help  me to  project the tag. But I will be using the metastack whenever possible


How do I get larger bubbles in my finished beer?

Question: I keg and force carbonate, and my beer has really fine bubbles. Is there something that I can do (turn up the pressure, maybe) that will give me larger, coarser bubbles in the finished beer? Thanks!
Comment: Why do you want coarser bubbles?  I ask because the one time I got very large bubbles in my beer (not on purpose and I don't know why it happed) it had 0 head retention.
Comment: My impression is that bubble size goes hand-in-hand with body. More body, smaller bubbles; less body, larger bubbles. I couldn't say whether that has to do with unfermentable sugars or proteins or...
Comment: I was just looking for coarser bubbles to match my clone to the original more closely. It's not a major issue at all, but was just something that I was curious about.
Answer: Really, fine bubbles is usually what people are after.  Are you hoping larger bubbles will cure a different problem like head formation or retention?  This type of information might get you an answer more suited for what you need.  Bubble size is a tough thing to control and quantitate.  It involves the size of the nucleation sites and the amount of insolubles in the beer.  Its something the pros really struggle with too, and its something that brewing scientists still pore over in research settings.
In short if you want bigger bubbles, you need cleaner beer and cleaner glassware.
And more pressure will give you just more bubbles of the same nature.
Comment: As I just commented above, I was really just trying to closely match a clone to the original. The original has coarser bubbles that stick around a bit longer than my clone, and I just wanted to mimic that a little better. Thanks for the response.
Answer: When you say bubbles, do you mean the mobile bubbles that form near the bottom of the glass and migrate upward, or do you mean the cells in the foamy head that collects at the surface?
My understanding of actual bubbles is essentially what brewchez said above: it's a function of glassware and suspended particles in the beer.
Head retention however is a different topic, and if that's what you're asking you might re-ask your question in terms of head density, head retention, head texture, etc.


Thrift Saving Plan (TSP) Share Price Charts

Question: I'm looking for a good resource for TSP share price charts/visualizations.  Something similar to Google Finance's charts. Any ideas?
Answer: If you're looking to generate your own charts, you can get up-to-date TSP fund share prices in a Google Docs spreadsheet by "scraping" the data from the HTML of certain TSP webpages. You'll need to do this because the GoogleFinance function does not recognize "private" funds or collective trusts like those of the TSP.
See this thread for tips: Bogleheads • View topic - GoogleFinance price quotes for TSP Funds
Answer: The recommended way to track TSP funds in online portfolio tools is to track the underlying index and know that the results are pretty close.   Not a perfect solution: :(
Source including suggested ETFs: http://finance.yahoo.com/news/breaking-down-tsp-investment-funds-194600393.html
Related, but not exactly what you are looking for, Personal Capital will track your TSP holdings: http://themilitarywallet.com/manage-thrift-savings-plan/
Answer: TSP.Ninja http://www.tsp.ninja has all the TSP funds with good visualizations that are very similar to Google Finance.
Comment: This site doesn't appear to exist anymore.


How to upgrade solidity compiler in truffle

Question: I couldn't find a way to upgrade a version of truffle solidity compiler.
Also curious how to see that information for deployed contracts in truffle console
Comment: Oh well, I would love how to _downgrade_ solidity compiler in truffle.
Answer: You can force truffle to use a specific solc version by installing that version directly in the truffle directory.
For example on Ubuntu the following with force truffle to use 0.4.15
$ cd /usr/local/lib/node_modules/truffle
$ npm install firstname.lastname@example.com

truffle version will still show the default version but it will in fact utilize the updated version.
You can verify inside: /usr/local/lib/node_modules/truffle/package.json
...
"bundleDependencies": false,
  "dependencies": {
    ...
    "solc": "^0.4.15"
  },

Locations on Windows
%AppData%\npm\node_modules\truffle
%AppData%\npm\node_modules\truffle\package.json

Comment: didn't work for me
Comment: I had pragma 0.4.19 in my files, and truffle complained even after I followed your instructions. Had to change it back to 0.4.18. package.json has .19.
Comment: Could you please elaborate @ulu ?
Comment: I'm trying the latest development version of solc, but I like the truffle testing framework.  Is there a way to force truffle to use that one?  Obviously the npm install path won't work -- it doesn't know about 0.4.20 at all.
Comment: PS.  I see the comment in solcjs README about using the latest development snapshot.  That seems to be what I want, but I don't know how to integrate that with truffle -- it seems better suited to a standalone js app that invokes a contract via solcjs.
Answer: If you're using ^v5.0.0 (including beta releases), you can bring your own compiler by adding this in your truffle config file (in this example it's set to 0.4.25):
module.exports = {
  ...
  compilers: {
    solc: {
      version: "0.4.25",
    },
  },
  ...
};

You can query the list of available compiler versions by running this:
truffle compile --list

Comment: Only be aware that when using this method, if you run the `truffle version` cmd in the same dir where config file resides, it will show the solc version specified in the truffle config file. But when you run the same command in another directory, it will default to its internal solc version.
Comment: Hey @johnblair, I recommend you switch to [Hardhat](https://harhdat.org), which caches the compilers.
Comment: Problem with this is downloads the specified version for each compile rather than store it once and reuse - any ide how to fix this? Note: I installed the version into the global npm directory but truffle doesn't seem to use that version in my project.
Answer: After a couple of attempts, I've made it by uninstalling and installing truffle, exactly as described in here:
npm uninstall -g truffle
npm install -g truffle

That updated Truffle itself though, along with the compiler.
Answer: You need to upgrade your truffle to do that.
npm install -g truffle@X

For example, to get solc 0.4.11 support, install truffle 3.2.2 or above.
npm install -g email@example.com

or
npm update -g firstname.lastname@example.com
Answer: Check your solc compiler version using the following command -
solc --version

Then you can use following commands to uninstall solc(solidity) compiler and install it again. It shall give you latest version(0.4.11) -
npm uninstall solc -g
npm install email@example.com

Check the solc version after installing it again.
In order to see the information of contracts, once you login to truffle console and run "compile" and "migrate" one by one. After that, You just need to type your ContractName or ContractName.abi  to get the contract information.
Comment: Truffle has solc compiler in it. and my question is how to figure out which solc version is being used in truffle. simple as that
Comment: @rstormsf Your question is about changing the version, not figuring it out. To figure it out, try `truffle version` or look in build/contracts/YourContract.json and scroll to the bottom to look at the "compiler" object which should say `"name": "solc", "version": `.
Comment: it doesn't provide information on `solidity` version. how do you know that it will start using global solidity compiler. also, you need to prove in your response to show what was the version of solidity compiler and the new one when you installed it globally. Did you try it? How did you verify the new bumped version? You are saying that `abi` compiled JSON contract should have a version. I've looked into it and I don't see where is the version of the compiler.
Comment: Edited the answer to check solc compiler version, you can check it before uninstalling it and then install it either globally or in the project directory as per your requirement. I did not try it again, but it should work this way. Let me know if this doesn't work for you? Also for contract information, I did not say that abi would have solc compiler version, please read carefully. I said typing contract name or contractname.abi in truffle console would give you information about the contract - like available functions, attributes etc.
Comment: Ok, My question is how to know which compiler version is being used in truffle. How to change it, how to read it. That's the exact question I'm asking. Please read my original question carefully
Answer: On your project root directory, there's a file named "truffle-config.js"
Inside this file, you can find a solc config, and uncomment version line, and then put your prefer version. (ex: 0.5.7)
compilers: {
    solc: {
       version: "0.5.7",    // Fetch exact version from solc-bin (default: truffle's version)
      // docker: true,        // Use "0.5.1" you've installed locally with docker (default: false)
      // settings: {          // See the solidity docs for advice about optimization and evmVersion
      //  optimizer: {
      //    enabled: false,
      //    runs: 200
      //  },
      //  evmVersion: "byzantium"
      // }
    }
  }

After this, just compile and truffle will download that version of solc automatically!
$ truffle compile

Comment: Didn't work. It didn't download the new version and kept using the old one, despite de setting in the config file.
Answer: Run uninstall and then install commands to get your Truffle and solc compiler upgraded to the latest version:
npm uninstall -g truffle
npm install -g truffle

Important: you may need to close the terminal and open it again to use the latest version.
Note: to check your current version execute:
truffle version

Answer: In the latest truffle after 5.x.x, it is possible to specify compiler version in truffle-config.js:
module.exports = {
  networks: {
    ... etc ...
  },
  compilers: {
     solc: {
       version: <string>  // ex:  "0.4.20". (Default: Truffle's installed solc)
     }
  }
};

Reference: https://github.com/trufflesuite/truffle/releases/tag/v5.0.0-beta.0#specify-a-solcjs-version
Comment: Is it possibl to just get it to download the compiler once instead of with each compile? Thanks. Note: Installing into the global npm directory for truffle did not work.
Answer: just responding as faced this issue in July 2020 and it took me quite a while to fix it as there aren't many resources for Solidity v0.6
So, here are things that I did to get my code compiled successfully.

Update Truffle, if you installed truffle before a significant amount of time to your development(I used it for a gig 6 months after I installed it as I was just playing around at the time and didn't started learning "actively" until recently).

Set compiler version for in "truffle-config.js" (make sure to use the current version as if you are using a library like OpenZeppelin-Contracts as there might be contracts in there using a different version of solidity than yours.

Usually, the second solution should be enough for you to get up and running. But In my case, I had to manually install "Solc" with "npm install solc" (inside your project directory). This installed solidity compiler 0.6.10 for me.

Yes, it required me to do all three steps to get my code to compile successfully. I hope this helps someone
Answer: You need not to uninstall truffle just install your required version by these commands.
For Ubuntu 16.04(suppose I want truffle v4.1.7):
sudo npm install -g email@example.com

Check truffle version:
truffle version

For any help with truffle commands:
truffle --help

Answer: If you just installed Truffle and want to use older version of Solidity, you can simply specifying the compiler version in the truffle-config.js file:
  ...
  // Configure your compilers
  compilers: {
    solc: {
      version: "0.5.11", // Fetch exact version from solc-bin (default: truffle's version)
      ...
    }
  }
  ...

If this doesn't work for you and you are compiling your contracts using VS Code extension, most likely you will have to change the compiler version of the extension. Check this answer to find out more.
If you want to use newer version, you will have to upgrade or re-install Truffle itself. To check the latest version of the compiler, type truffle compile --list
Answer: As @Adam Lemmon suggested, you can hardcode the version that the global truffle installation is using, or you can just update the version in the pragma solidity ^0.4.15; statement of your contract.
Note: This will only work if you are not inheriting from any other contracts. If the parent contracts use a higher solidity version, you'll get the compilation errors.
Answer: You can't specify version, but we can specify some params as well:
http://truffleframework.com/docs/advanced/configuration#solidity-compiler-configuration
solc: {
  optimizer: {
    enabled: true,
    runs: 200
  }
}

https://github.com/poanetwork/poa-bridge-contracts/blob/master/truffle.js#L49
Answer: I used next commands upgrade truffle when I want to compile solidity version: pragma solidity ^0.4.25;
npm uninstall -g truffle
npm install -g truffle@beta

Answer: I messed around with manually changing the installed truffle package's solc dependency, however the versions weren't compatible, it wouldn't run my tests properly and it felt very hacky.
Instead I just installed the truffle package that naturally had a dependency on the solc version I wanted. In my case I wanted solc": "0.4.24" so I installed "truffle": "4.1.14".


Add line feature using bearing

Question: QGIS 3.4.Is there a way using advanced digitizing to use a bearing, i.e. N 45° 15' 25" E as the angle?
Answer: QGIS generally doesn't deal well with directions in degrees-minutes-seconds format, let alone quadrant bearing format (sometimes called azimuth and bearing).
This type of format is generally only used for US land surveys. The Azimuth and Distance plugin is the only tool in QGIS I know of that will accept land survey data in this format.
If this plugin doesn't do what you need, you'll probably have to convert your bearings to decimal degree. Try one of the methods discussed here, use an online calculator, or use a spreadsheet.
This Q&A suggests that a free tool called "Copan" might be helpful.
Answer: I would recommend working with QGIS Python Plugins Repository

"Geodesic Measure Tool" measures distances using the WGS 84 ellipsoid and includes the bearing or heading between points. It will even saves the measurements as a layer.
Shape Tools is a collection of geodesic shapes and tools. Create ellipse, line of bearing, pie wedge, donut, arc wedge, polygon, star, ellipse rose, hypocyloid, polyfoil, epicycloid, and heart shapes. Tools include "XY to Line" tool, densify lines and polygons along geodesic paths, geodesic line break, geodesic measuring and create a measurement layer, geodesic scale, rotate, flip and translate tools, and digitize points at an azimuth & distance tools.
Comment: The Azimuth/Bearing input appears to only use decimal degrees.

Add line feature using bearing


Site quality in questions and answers solution

Question: Lately I have seen and talked to people about the level of quality and ideas how we can improve it.  Since a majority of people suggest another addition of a closed reason I am partially against it based on the user being new and unfamiliar with our format.  Per some discussion in the chat it was brought up we could automate our comment system (AutoReviewComments - Pro-forma comments for SE).  So instead of a closed apocalypse I thought we could come up with a way to address quality questions and answers with a default comment in the hopes it will encourage the user to make an edit.  What questions and answers do you suggest we should have a default comment for?
Answer: In addition to the pre-fabricated comments section, I think we should expand our faq to include suggestions on how to write decent quality questions for common problems. An example of something to add would be:

Q: How can I write a good question to achieve a certain effect?

A: Please, for the love of pixels, show us what you have tried!

We can only write so much within a comment, so the idea here is to provide a rich resource for users to visit that is longer than 600 characters
Comment: While I agree in providing a rich resource sometimes the amount of material can be a deterant
Comment: We can link to meta posts from the faq, right? We can vote on the comments or create a wiki-style post and use that instead of charging the faq too much.
Comment: I think a wiki style post would be good.


How do modern philosophers oppose relativism?

Question: If my understanding is correct, Plato's theory of forms was developed to counter the relativism of Sophists such as Protagoras. His theory does not seem to have modern followers, as far as I know, yet how do modern philosophers justify the existence of "The Good" for example? Or more generally, how do they oppose relativism?
Answer: Most contemporary philosophers accept that relativism is self-refuting.
By "relativism," in this sense, I mean what I take Plato to being arguing against in the dialogues Theaetetus and Sophist. It is committed to two views:

There are no objective truths. By "objective truth" I mean a truth which one must believe, or else be rightly considered irrational. Similarly, we could understand a truth to be objective if a being — even an alien from another planet — would agree to it, were the alien to have knowledge and understanding of the same things. The mass of a pebble is an example. You can express it in English, Spanish, Korean, or hexadecimal notation, or (maybe?) Klingon, but it all translates to the same fact, or else isn't true. Relativism denies that there are any truths like that.
There are, however, local truths, says the relativist, whose truth is merely relative to the culture or other group believing them. Relativists say about these latter kinds of truths that they are "true FOR X" where X is a culture or community, or even an individual. Relativists do not therefore deny the existence of truths, but understand all truths to be relative truths with currency only among a community that believes them.

This form of relativism, which we might call "general relativism" to separate it from "moral relativism," is generally considered self-refuting, and therefore untenable. It suggests that there are no truths that hold objectively, but it insists that the claims above are objective truths.
Consider, that is, what a relativist would have to say about relativism: "Relativism is true for me but maybe not for you," in which case we have no reason to accept it. Indeed, if the relativist is right, relativism can have no sway over us, because a thing can be made true simply by being believed, and made false simply by not being believed. Or the relativist could say  "Relativism is objectively true," in which case Relativism simply contradicts itself.
Comment: Are there serious modern formulations of relativism on the antique lines that you describe here? I'd imagine a modern strain of relativism to be more nuanced: not claiming that `A believes X` ≡ `X is true for A`, but that the truth-value depends on a network of beliefs and interpretations of personal experience, none of which can be objectively justified but which in different people may give rise to diverging opinions. For instance, they might describe your rejection of relativism itself as being due to having social consensus as a priority, which may lead you to devalue other's experiences.
Comment: Isn't there are third possiblity - There are objective truths but they are not obtainable by finite creatures like humans, who are thus limited to perspectival or relative truths. One might suppose that there is a (hypothetical) infinite being who can obtain objective truths, but this being a (hypothetical) objective truth is also not obtainable by finite creatures like humans too.
Comment: @Mozibur Ullah. Of course! I didn't say anything about other positions. Embracing limited perspective does not mean embracing relativism, because you can believe that despite their limited perspectives, and despite their having to understand the universe through the filters of their concepts and languages and senses, people sometimes get things *right*, at least a a degree. See Ron Giere's *Perspectival Realism* for one of many, many examples of such non-relativist views.
Comment: @Niel de Beaudrap, Well, among professional philosophers, generally no, as an implication of my suggestion that they almost universally reject relativism. Yes, there are various postmodernist positions similar to what you describe. I think they generally embrace a false dichotomy: (a) we can be objective and/or know objective facts, OR (b) there are no objective truths and truths we express are merely the result of cultural processes and not the world. They tend to argue for (b) by rejecting (a). But I think BOTH (a) and (b) are false. We are ignorant, but approach the world by degrees.
Comment: @ChristopherE: Would anyone who seriously entertained relativism follow that line of logic, though? You simply assert the existence of objective truth: someone who *didn't* presume the notion of objective truth could acknowledge it as something which would seem convincing, and could be approximated through certain social practises, but which was problematic and elusive upon examination. They could even acknowledge that there are good heuristics for understanding the world, which however could not be established beyond all doubt; of which "there is no objective truth" would be one example.
Comment: @NieldeBeaudrap Ignore my own view if you like. I still think many non-philosopher academics argue via the disjunctive syllogism I suggested. Not (a), so (b). My point is not that they should accept objective truth, but that arguments against (a) considerably underdetermine (b). And I think that some casual relativists back off of relativism when they accept that those aren't the only alternatives.
Comment: Thanks for the reference - I was only using 'perspective' in its usual generic sense, I wasn't aware it was (part) of the name of some theory!
Answer: Badiou, a French philosopher counters the modern form of sophistry (Postmodernism and other ills) by what might be seen as a modern form of Platos forms by steering philosophy towards a philosophy rooted in mathematics - he takes his starting point the axiomatisation of it within set theory - that is ZFC.
One might say he's resurrecting a grand narrative.
Philosophy for him is a point from which three 'truth procedures' are suspended from: Love, Science & Art. (Being an avowed communist of the Maoist kind - he is rigourously atheistic, but for the religously inclined philosopher one may suppose that Religion comes under Love).
Nina Powers, a British Philosopher (a follower of Badiou) takes a more modest view of philosophy and considers it empty of content (or taking a 'Buddhistic' view  - lacking its own essence), and thus by only embracing one of those three conditions can it be said to have content or substance.


What is a "dead raise"?

Question: I've been watching some episodes of Poker After Dark (the tournament episodes) and heard the dealer say that if the players try to straddle, it will be considered a "dead raise". But what exactly is that? I can't seem to find this term defined anywhere.
Answer: When you straddle in the traditional sense in a poker room that allows them, it's considered a "live" straddle. Several popular variations of straddling exist, but one common element is that they're "live."  This means that the straddler is paying for the privilege of acting last in the pre-flop round of betting. If the dealer in your example is saying that it's a "dead" raise, that simply means that the bet is not a live straddle but rather just a bet placed blindly that doesn't confer any additional benefits.
Comment: If the dead raiser is UTG and puts in 2 BB before the hand and it's called around back to him, he doesn't get to re-raise himself. If this were instead a live straddle, he would have the option to effectively raise himself.
Comment: Even though it is not a live straddle, as you said, it would still be binding and would allow the player to, effectively, act last, correct?
Comment: If the dealer declares the straddle to be a dead raise (usually because he did not put the straddle out before the dealer started to deal the cards), often he will allow the player to take the raise back if no player has yet acted on his hand.  The reason for this is to avoid confusion.  Once a player acts on his hand, the money stays in.  Also, a dead raise means that he no longer acts last.  His action is first - and that action is a min raise.  He does not get another chance to act on his hand again if no one raises like a true straddler would.
Answer: It's when the UTG player posts an additional blind and thus is given the chance to act last. This action is not considered a raise to the rest of the table.
Answer: From what I have heard , a "Dead Raise" its when you raise without any change to get the pot. You trying to bluff your hand its sure they will pay.
Comment: I think you might be confusing this with something like "drawing dead."

What is a "dead raise"?


What is the past tense of suru (do), which would be did?

Question: I was writing a story for Wattpad, in which the two main characters spoke both Japanese and English, when I wanted one to say "You did no better than I". I looked it up in my dictionary, and I could not find the word 'did'. Another way to say that sentence would suffice, but I would appreciate how to say the word 'did' in Japanese.
Comment: I don't feel like "You did no better than I" can be translated using した...
Comment: agreed. can we get more context? we might be able to help with better phrasing given a bit more context
Answer: The past tense of する (suru) would not show up in a dictionary as it is a conjugation of a verb. Conjugations typically do not show up in a dictionary. For that, you're better off consulting a textbook, to pick up verb conjugations as you learn the language.
That being said, the past tense conjugation, sometimes referred to as the た(ta)-form, for する (suru) is した (shita).
Also, for what it's worth, I'm not sure what tone your character is speaking in, but for formality's sake, there are separate conjugations for past tense depending on how polite you'd like to sound. した(shita) is standard, but for more polite, you might want to try しました(shimashita).
Comment: I'd like to hear how non-native learners are taught the past た. It seems to me a particle, though dictionaries say it's a helping verb. It conjugates! though Japanese conjugations are nothing to do with the tense, but only to do the connection to the next word.
Comment: we can chat about my experience as a student sometime, if you have questions about that :) I imagine learning Japanese as a non-native, and the way we refer to things, is very different


How do I seal between the soffit and frieze board?

Question: I have a small gap between the wall and the porch roof, probably 1/8 inch or so. I was planning to use caulk to seal it up, but I'm not sure if that is the best product. I don't want to use the expanding gap filler (I've had bad experiences with it). Is silicone caulk appropriate, or should I use something else?
Comment: I wouldn't use roof patch. The roof patch I've seen turns hard and tends to crack. Also a mess to work with.
Comment: I would use quality exterior paintable caulk or clear silicone caulk. If you are concerned about that small crack, what do you intend to do about that big hole?
Comment: due to coloring matching issues I'd use roof patch.
Comment: I'm going to fill the hole as well. We have some ants, and I think this is where they are coming in from
Answer: In this case, a caulk that matches the dark frieze board will probably be least conspicuous. You should be able to find a silicone or urethane that's very dark but not black. It might be called "dark walnut", or maybe "charcoal gray".
I'd avoid latex caulks as they don't bond particularly well and they shrink substantially.
If the cavity is deeper than 3/8" or so, pre-fill with foam rope caulk to act as a backer.
Answer: Caulk. either clear or a color that matches one side of the gap


Is there an adapter to allow a camera to control focus or aperture of a manual focus & aperture lens?

Question: I recently bought the Sony Alpha a7. In a bid to get an affordable portrait lens, I rushed to get the Rokinon 85mm f/1.4 only to realize that there is no communication between the camera and lens. Now that I now understand how a manual lens works, I was wondering if there is any adapter of some sort that can help with either controlling the aperture or focus from the camera, or even both?
Answer: No, there is no such adapter. The Rokinon lens a manual-focus, manual-aperture lens. It does not have a built-in focus motor, nor can it interface with a focus motor in a camera body that might have one (the Sony a7 does not).
Comment: Thank you :(  It is quite the learning curve. Hopefully I can trade it in soon.
Comment: @AyotolaTehingbola Expect to pay much more for an AF-capable lens with the same optical quality as the Samyang (Rokinon) 85mm, f1.4 lens. If you are shooting portraits and not moving subjects, I would honestly advice you to learn how to focus manually. I have never used the Alpha a7, but it very likely has some kind of focus aid, making the job quite easy.
Comment: The A7 should have focus peaking that helps with manu focus. For portraits where you ask the subject to hold the pose, focusing speed probably won't matter that much. Focus peaking may help you nail the focus in the eyes. If you need to shoot more candid shots, then an AF lense is probably more appropriate. Expect to pay more.
Answer: While that may be true of some lenses (that no electronic connection can be made to the camera), I have seen shops that offer lens modification to allow some high-quality film-era manual-focus lenses to allow their aperture to be controlled and/or to pass aperture info to the camera. I think some even have a chip that somehow identifies the focal length, etc. With modification, some lenses, when focused, trigger the focus magnifier, like the modern Sony/Zeiss manual-focus lenses (e.g. the Zeiss Loxia line). I saw a shop that was doing this for some Contax SLR (and G-series rangefinder) lenses; they had to be the later models that allowed aperture to be set by the camera.
Personally, I love using manual-focus lenses on the Sony A7R. And none of mine have any electronics. You can still push the button to turn on focus magnification and check that important elements are sharp. Once you are used to the process, it's really not hard, though no adapter or modification will add auto-focus to those lenses.
It would be cool, though, if Sony ever decided to build an auto-focus body (like the Contax AX, where the film plane moved forward and backward to achieve focus). Sony actually already performs a fair bit of sensor movement in their IBIS technology, so it would just be an interesting "next step" to allow some view camera -like rear-standard movements, which could also be further extended to movements designed to achieve focus at some position in the image. That could end up making an A7 -like camera into a system with a body as large as a typical full-frame SLR's, but I think there would be a great market for it, especially for product photography and "trick" videography. (Are you listening, Sony?)


Can I get a patent from a device which was made with open source parts?

Question: Can I get a patent for a device which was made with open source parts? I have some concept of a device but it's made with Arduino and other (Arduino-friendly) components. Is it possible to pass all appropriate steps to get a patent?
Comment: AFAIK if you have a new and unique combination of parts that no one else has used then you could get a patent.
Comment: @Nick Alexeev How about the Meta site? Although strictly off topic this is interesting and very relevant to electronic design.
Answer: Whether or not you use open source parts is really irrelevant. What matters is whether your invention is useful, novel and non-obvious. Useful means it has fulfills a purpose. Novel means it hasn't been thought of before. Non-obvious means someone skilled in the field wouldn't think it straightforward. This is a brief explanation, there are more rigorous legal definitions.


Android won't factory reset

Question: I've been having trouble with my phone lately so I decided to back up my data and factory reset, but every time I want to do it the "reset phone" button does not work, I can't even press it. I have also tried to hard reset but when I get to the screen where I choose factory reset (the screen where there is a android guy saying "no commands"), there are no commands to choose so that is also a negative for resetting.
Comment: Sounds like you'll have to resort to `fastboot` and stock firmware.
Comment: how do i do that
Comment: A quick Google search: [XDA Moto G Flashing Guide](http://forum.xda-developers.com/showthread.php?t=2542219)
Comment: Maybe you check our [factory-reset tag-wiki](http://android.stackexchange.com/tags/factory-reset/info), which also mentions an alternative way to do a factory reset, not requiring `fastboot`. Also see: [How to do Factory Reset](http://android.stackexchange.com/q/25701/16575)
Comment: Oh, wait: "The Android guy saying "no commands"? That sounds as if you've already been to your devices *custom* recovery and have wiped `/system` and/or `/recovery`, so it no longer has any OS installed. In this case you've really messed up, and flashing a new firmware via [fastboot](http://android.stackexchange.com/tags/fastboot/info) is the only way out.
Answer: don't worry. Do just what I say:

Turn off you Motorola Moto G 2nd Gen(I mean moto G2).
Afterwards press and hold the Volume Up and Volume Down for about 2-3 seconds.
While still holding these keys press the Power button for a short while and release all buttons.

Then select option Recovery by using to navigate Volume Down, and to confirm Volume Up.
In the next step hold down the Volume Up for a few seconds when an Android logo appears on the screen.
While holding the Power button, press and release the Volume Up key.
Press Volume Down to choose "wipe data/factory reset", and then push the Power button to confirm.
Select "Yes--delete all user data". Use Volume Down button to scroll and Power button to select.
To restart the phone, select "reboot system now".

Success! The hard reset is done!

Source : All credits go to hardreset.info
Comment: Just had the same problem with a Moto G2: I wasn't able to click the button to reset. So I tried your instruction and it worked perfectly. Thanks.
Comment: This will not help the OP, his OS is corrupted according to the conversation above. Consider providing fastboot flashing instructions rather than reset instructions which he has already tried.
Comment: @Aaron Gillion - how do we give flashing instructions ? I face the same issue with android one and also if it swtches on its stuck on the welcome screen.
Answer:
but when i get to the screen where i choose factory reset (the screen where there is a android guy saying ''no commands''), there are no commands to choose so that is also a negative for reseting, thanks in advance...

This 'no commands' screen is actually part of the process. When you get this screen, continue with step 6. as explained earlier.

While holding down the Power key, press and release the Volume Up key, then release Power'

I also got the 'no commands' screen but after checking this motorola support page I found roughly the same steps as described earlier and it worked!
Good luck!!
Answer: Try installing TWRP, or just unlocking the device. when you unlock the device the device will factory reset and if you want you could install TWRP. to unlock your device, open "Developer Options/Settings" in the settings app and click "Allow OEM Unlock[ing]".
Then enter fastboot and on your computer write:
<code>fastboot oem unlock [Unlock Key From Motorola's Website]
</code>

Android won't factory reset


Are physical hardware repair/modification questions on topic? Should they be?

Question: This is a question about Apple hardware. It would be great if users could get answers to questions like this. But does the question require sufficiently different expertise from the sort of questions that make up almost all the rest of the posts here that it would be unlikely to get good answers, or does that matter?
Answer: My take is they absolutely are on topic (and should be as well).
1) This site explicitly is about apple services - one of which is Apple's repair service. The average user might reasonably ask some basic question about how to understand the makings of the product so as to weigh their options.
2) Apple hardware is totally on topic. This user has a specific, definite problem they are seeking so solve and it involves iOS hardware.
If you take the long view - six months from now - having an unanswered question that is good, clear and on-topic isn't really a problem. I have found great questions to answer that have been here for 8 months or more. It's up to the OP to promote the question, be patient or flag it to move if another site has a better shot at asking.
In this case - I happened to know the answer - but even if I didn't - there are many people here who have had their phone break and could share their experiences. Some may have done a glass repair and could share their triumph or tale of woe. In the end - the OP was able to realize paying for a local tech was worth the money to minimize his risk / time to DIY.
Comment: So, then would [this question](http://apple.stackexchange.com/questions/25101/difference-between-phillips-00-and-000) be on topic?
Comment: You're linking to the same question the OP linked to - so yes! (my take on it at least)
Comment: No, I'm not. Try it again.
Comment: Totally - same rationale - the user didn't explicitly say why they needed to know 000 vs 00 - but a 00 is needed to properly open a user-accessable bottom case. I don't know of any 000 screws offhand that Apple expects a user to adjust - but it's a great question as well from where I sit :-)
Comment: Ah, I get it now!


Skeleton screens - do we display them in case of lack of content or lower amount of content than suggested in skeleton screens lay out?

Question: Currently, we add skeleton screens with a progress bar while the page is loading with data (in a data-driven platform). I'm wondering what to do in the case where after loading for some time, no data is available, or i.e. just one card is available instead of a few cards - like the skeleton card as suggested. Do we still use skeleton cards in this case? What's the usual flow?
Comment: Is this a common case, where your content may just be a small amount?
Comment: I would say it varies from the company and how much data they have within the platform - how long they use the platform. The most what concerns me what in the case of 0 data...
Answer: I would still use them as if they are just containers, empty albeit, but still the layout that you would expect. If there is no content, then the container will be empty with a message inside informing the user that there is no data available.
Comment: By zero-state you mean an empty state? We might be referring at the same thing but different terms, then yes. Empty states seem to be the most overlooked UI elements.
Comment: like a zero-state info?
Comment: yes indeed :) thanks
Answer: Here is a great study on skeleton screen patterns: https://uxdesign.cc/what-you-should-know-about-skeleton-screens-a820c45a571a by Bill Chung (designer @ Shopify).

Skeleton screens create the illusion of an instant transition. (Bill Chung)

To mitigate focus on the loading process, versus the actual content that is loading, Wroblewski introduced a novel new design pattern — the skeleton screen. In his own words, they are "essentially a blank version of a page into which information is gradually loaded."
(-Luke Wroblewski)

An overview of the important points mentioned by the author (Bill Chung):

"When designing loading experiences, strive to progressively load content, replacing skeleton placeholder objects with content like real text and images as soon as they are available."
"Grey or neutral-toned filled shapes, commonly called placeholders, meet the user instantly upon user interaction with calls to action or links. The placeholders (the so-called "bones" of the skeleton) are then replaced with the actual site content, and the illusion is complete."
60% of test participants in the author's skeleton screen study perceived that the animated skeletons represented a shorter duration. "Skeleton screens that leverage motion that moves from left to right (e.g. a wave or shimmer like animation, much like Facebook or Google uses) are perceived as shorter in duration than skeletons that pulse (opacity fading in and out)"

Therefore, to answer your question: instead of just a blank card, showing the blank version of the page with a loading animation from left to right could be an approach.


Web-based Backtesting for Options Traders

Question: Is there a good web-based option for back-testing of equity options trading strategies.
Answer: GetVolatility features a pretty robust backtest capability. But be aware, it's paid and somehow expensive, since it focus on professional traders.
Answer: See this workaround suggestion for Quantopian:

As of now Quantopian only offers equity trading. However, I think it would be fairly easy to hack something together for the sake of backtesting.
For simplicity, say it's a European call, I guess you could calculate the Black-Scholes price and buy at time i. Then down the line at e.g. time i+90 (days) you could see if you would get a positive payoff, i.e. max(S-K, 0) > 0 and in that case submit an order.
Actually Pandas can be used to fetch options prices from Yahoo! Finance (see http://python4econ.blogspot.hk/2013/02/building-stock-options-historical.html), but I don't think it's possible to get historical option prices anywhere for free. Thus, you might have to stick with your Black-Scholes price (even though the option you calculate might not be available in real life).
Answer: Thinkorswim brokerage platform has some backtesting capability. Not sure how good it is.
Comment: I actively use Think or Swim for both trading and teaching. It has the ability to do fairly robust backtesting on options trades with its trade simulation and ThinkBack tools. The system isn't perfect and I have seen it mess up, but for general purposes, it is pretty good.
A hint, if you fund a ToS account for $50 they give you the whole ToS platform and data for free. There is no requirement to trade and no fees. When you shut the account down you get the money back.
The one major complaint I have is that there is no way to export the data for more robust testing.
Answer: Optionsprofitcalculator
primarily lets users get an overview of option position prices in regard to underlying price at expiration. But you can also fiddle around with certain fields if you know the backdated options values. You just have to expand "manual entry options."


Fallout Shelter Losing Resources After game is Closed

Question: So, I've been playing Fallout Shelter since it came out, and quite frankly I'm a little baffled as to how people get so far in the game. So far every vault I've had I've lost because of little thing I can't seem to get around. So, it's like this, I'll be playing upgrading my vault, collecting resources and what not. Then I'll have to do something where I can't play like go to bed or something, I've heard that the game runs in the background even after I close it for a few minutes and will notify me if my production rooms are ready then stops. But when I get back in the game, all my resources are completely depleted, and my dwellers are dying and are sick. This is completely irreversable as the rate of my resources being depleted as I regain them is 5 to 1. Am I doing something wrong? Does this happen to everyone?
Comment: Note that the game itself mentions that it runs for a little while when you close the app (in my experience that amount of time is probably 2-4 minutes). This behavior apparently persists even if you [close the app manually](https://support.apple.com/en-us/HT201330): I have had it continue to give lock-screen banner notifications.
Answer: The game does continue to run for a little while after you leave. This is to encourage players to play for extended periods of time instead of just quickly checking on their vaults. You need to make sure that you have enough resources to survive the period in which the game runs yet you aren't online.
I would check that you have enough storage. You might not even have the capacity to store enough resources to survive closing the game.
Answer: Are you sure you are completely logging out of the game??  Don't just click the game off. Go to the bottom right corner and click on the pip boy. The first option lets you log out. Click on the gears symbol then main menu. After that you can click out of the game and it won't keep running forever depleting all resources.
Answer: The game sets a timer when you log off, for 3 minutes it will continue to run as if your still playing except ofcourse you cannot collect resources (i dont know if a mr.handy will collect for your during this time) and no attacks or disasters will happen.
After 3mins the resources also stop moving and the only things still running are the timers on your rooms, quests and wasteland explorers.


Does all the exoplanets orbit the same direction?

Question: In one stellar system like our milkyway, all the planets orbits in the same direction. But are exoplanets orbitting in the same direction as we (earth) do, or is there a higher percentage which orbit in one or the other way? If so what could be the reason for that?
Answer: All planets in a planetary system should orbit in the same direction. However, this direction varies among different planetary systems. The direction that planets will orbit, for any planetary system, depends on the molecular cloud that formed them. The reason for this is conservation of angular momentum.
Before a star and its planets exist, there's just a cloud of disorganized gas and small molecules. The Solar System formed from such a cloud around 4.6 billion years ago.
On that scale, there is some small amount of rotation within the cloud. It could be caused by the gravity of nearby stellar objects, local differences in mass as the cloud churns, or even the impact of a distant supernova. The point is, all molecular clouds have at least a little rotation. The direction depends on a number of factors, so some clouds will turn clockwise, and others will turn counterclockwise.
In a large system like a molecular cloud, each particle has some angular momentum, and it all adds together across a very wide area. That's a lot of momentum, and it is conserved as the cloud continues to collapse under its own gravity. That angular momentum also flattens the cloud, which is the reason why the Solar System is near-planar.

When the cloud finally collapses, it forms a star and shortly after planets. However, angular momentum is always conserved. That's why all the Solar System planets follow the same orbit, and why almost all of them rotate in the same direction. There's nothing to turn them the other direction, so they will continue spinning in the same direction as the original gas cloud.
There are a few exceptions, though. Whenever objects formed in such a way that sent them orbiting the opposite direction, they usually collided with objects going in the same direction as the original cloud. This destroyed any outlying objects or sent them in the same direction as the original cloud.
Still, two huge exceptions are planets Venus and Uranus. Uranus spins on an axis of almost 90-degrees (on its side). Venus meanwhile spins the opposite direction as Earth and the other planets.
In both cases there is strong evidence that these planets were struck by large objects at some point in the distant past. The impacts were large enough to overcome the angular momentum of the bodies, and give them a different spin. There are also a range of other theories; for example, some astronomers think that Venus may have been flipped upside-down. Point is, there were irregular events that happened to both of these planets.
Overall, what I described applies for all planetary systems. To answer your question, it depends on how their cloud rotated. The cloud that formed some planetary systems may have turned counterclockwise, just like for the Solar System (at least, it appears counterclockwise from above Earth's north pole). The cloud for others may have turned clockwise. That's why not all exoplanets systems will have the same orbital direction as Earth; however, typically all planets in a planetary system will share the same orbital direction.
Comment: More than outliers. About one third of hot Jupiters show a misalignment between stellar spin and orbit. However, I think you are probably right that more distant planets are likely better behaved, but there is little evidence either way.
Comment: Unfortunately, there is plenty of evidence for some planets not sharing the same plane and even being retrograde with respect to the stellar spin. Nothing wrong with your description of what should happen, but clearly it doesn't always turn out that way.
Comment: @RobJeffries I know. I thought mentioning the outliers would put me on a tangent, but I guess I'll mention it.
Comment: I like the term "better behaved".     :-)


Ways To Test iMac G3 Before Buying

Question: I am going to buy an old iMac G3 Over the next couple of days/weeks, and I want to make sure that I am buying a system with no problems. I usually ask for the serial number and good pictures before buying, but I want to know what to do when I physically meet the person I decide to buy from. What should I do when with the buyer to test the system to know what defects it may have? The system would either be running Mac OS 8 or 9 (classic), or OS X. If there is a set of things I should do, or a program I should run what would that be?
Comment: Make sure the install disks are there and plan on buying a new harddisk...
Comment: Ok, I will do that. But what about other hardware issues? I have never owned a iMac G3 before this, but I use modern Mac OS.
Comment: I'm *super* curious what you intend to use this for; it doesn't sound like you're a vintage computer collector. Do you just like the aesthetics and want a good word processor?
Comment: I want to get into vintage computer collecting, but I haven't really been able to experience the original use of these computers. I do like the aesthetics, but that is just one factor in why I am buying this. But, I am not buying it for a word processor. I already have a MacBook Air (which I am using for this). I just want a way to test one that if I choose to buy one of the ones being sold in my area
Answer:
I am going to buy an old iMac G3 Over the next couple of days/weeks,
and I want to make sure that I am buying a system with no problems.

Assuming you're getting the Bondi-Blue iMac G3, you're looking at a machine with 20 years on it.  Getting one with "no problems" is a tall order and akin to buying a "reliable classic car."
Some of the issues you can expect:

brittle plastic
malfunctioning CD-ROM
leaking capacitors
failing IDE/PATA Hard Drive

If you get a machine that boots and runs, you're well on your way.  That said, this will run OS 8, 9 and OS X through 10.3 Panther.
What to look out for...

Make sure you have original install disks.  If you do, the second disk will have your diagnostic tools.  Boot that and run them

Run First Aid using Disk Utility.  If the drive is actively failing, this will tell you.

Bring an audio CD  with you to test out the drive and how well the speakers work

Determine whether you're getting the Rev A. or B model.  The B version had the ability to support more memory (512M versus 384M) and better graphics (6MB VRAM on ATI Rage Pro versus 2M RAM on ATI Rage)
Comment: "Getting one with 'no problems' is a tall order and akin to buying a 'reliable classic car.'" This seems a bit severe? I've never bought vintage computers, but I have bought a number of "retro" game consoles in my time, and they all worked and still work to this day. Cars have a lot more moving parts and generally require more maintenance than computers.
Comment: The difference between a console and a computer is the demands put on the drive(s).  Normally, console units load the software (game) into memory where it's used unlike a computer where's it's continually taxing it.
Comment: Huh. Sounds like OP should really plan on replacing the hard drive, but I'd imagine the rest of the unit is fairly likely to be in working order? There's the CD Drive, but I imagine that probably wasn't running full tilt most of the day.
Comment: I don't imagine it being very clean.  Maybe a good blast of compressed air will fix it, but if it was subject to any sort of moisture (i.e. humidity), the laser diode and/or lens may be damaged.
Comment: For me, I am luckily buying in a place where the climate is dry, and not near a major body of water. But, dust is going to be an issue for me. But, a good blast of compressed air should totally fix it like @Allan said.
Answer: I do agree with @Allan largely.
But to answer/elaborate the specific question: what you'd ideally want to do is run AHT. These used to be included on a partition of the install disks a machine would ship with, but the AHT (Apple Hardware Test) disk images are still available online. And though the AHT support page index is gone, you can find it preserved at the Internet Archive. So I wouldn't consider the lack of original install disks "the end of the world".

I actually wouldn't necessarily consider a bad HD a deal-breaker myself, either, depending on the model. They still make IDE/PATA hard drives. And one should be able to find disk images of old OS X and even Mac OS 9 versions pretty easily. With a paid Developer account, I believe Apple still hosts a Jaguar image (which includes an OS 9 image). Moreover, there were a lot of revisions of "G3" iMacs and assuming it isn't the original Bondi Blue, you might find one that can FireWire 400 option-boot to an external drive.
However, I can't re-emphasize enough the point about brittle plastic, and, in general, the difficulty in teardown and reassembly with a machine like this. I used to be an ACMT at a AASP back in the day, and these guys were a pain to repair back when they were still covered by AppleCare, and that was with service manuals and genuine replacement parts. And:

Most importantly, it can be quite dangerous to disassemble. Unless you're  quite comfortable with your knowledge of how to properly discharge a CRT safely, its yourself I would be worrying about first, before cracking one of these open. You would also need to be properly grounded for the rest of any surgery you attempt, because those boards will fry with even the slightest amount of static. And if you needed to Google "discharge a CRT"—don't even think about it.
On the other hand, if the CD drive is working and you've burned the right version of AHT onto a blank disc, and it runs, I'd say you're good to go. I don't know about you, but an original, first-gen iMac, with all discs, etc., and with everything in fully working order, would almost certainly be well above my price-point.
Answer: The main uses of the system should dictate a list of end-to-end tests. A couple examples:
Network/"Internet" access
I wouldn't get on the public network (none of your browsers will be secure), but you might want to at least have some transfer to your other home systems.

AirPort - it uses the older, original airport, it probably only talk to the old flying-saucer Airports.
Ethernet - your best bet. Everything is supposed to be 10mb compatible, but I'd bring the hub you will actually use, and at least get a green link-light on both sides.
Modem - This probably still works, but it depends on what you think of the words "hobby" vs. "fun".

Aging CD-drive
The HD drive concerns are valid, but also remember that your CD-drive is going to be getting old too. I had the CD-drive on a iMac G4 (lamp-style) fail, and soon after, the HD stopped spinning up, so for systems this old, you should think about both concerns.
Real mouse vs. "best" mouse
Some people loved the look of the "hocky-puck" mouse, others really disliked the feel. (I was neutral on that ), but I did find that a wired Mighty-mouse was my favorite mouse for this (it has "pill" shape that Apple stuck with when they upgraded).
If you will really use this system (for word processing of old games, etc.) you might want to get another mouse. You can even have two mice, if you need to compromise.
Printers
If you have legacy printer, of the right era, it will still work. With MacOS 10 you get a lot of language support out of the box, they make excellent non-internet "typewriters" for kids.
Comment: This is incorrect about "printers."  Any modern printer that supports the LPR or PS protocols will work here.  It's not limited to "legacy" printers.
Comment: True, if they choose to run MacOS 10... and driver updates might be hard to do from a fresh install in today's world. There's too many Apple printers to sort out the classic compatibility here.
Comment: No.  That is incorrect.  Mac OS 9 also used the CUPS printing system which meant any LPR or PS printer will work.  CUPS doesn't use printer drivers, they use PPD files which can be modified by the end user.
Comment: I can edit the answer if you want to include CUPS, I didn't use that much, but I did a lot of work on Apple-made printers, which is what I was specifically referencing by "legacy".  (We can't mark my answer community, anymore, can we?)

Ways To Test iMac G3 Before Buying


How to correctly play an arpeggio on the classical guitar?

Question: Im new to these arpeggios and I would like to know how to play this one specifically on the classical guitar. What are the exact notes?
Answer: Are you asking the notes or the fingerings? The notes from the bottom are E, E, G#, B, E.
The fingering depends on what position you want to play it in which depends on the context (the rest of the piece surrounding this). But assuming open position from the bottom:

The low open E is held from the previous measure.
The middle E is on the 2nd fret of the 4th string.
The G# is on the 1st fret of the 3rd string.
The B is the open 2nd string.
The high E is the open 1st string.

As for fingerings, these notes fall within the standard open E Major chord that you are probably familiar with so I'd probably just fret that but start picking from the 4th string.
It's not exactly an arpeggio as I'd define it in the sense the notes aren't played completely separated. It's an arpeggiated chord or a rolled chord meaning the notes are played in roughly the notated rhythm but each successive note (usually starting from the bottom) is played slightly later than the previous one. It's almost a harp-like sweep across the notes.
There are a couple ways to actually pick this. With a pick or your thumb you'd sweep down across the notes like a strum but slower. Or the method probably more appropriate for classical uses separate fingers for each string as shown here:
Answer: Following on from the previous great answer - a couple of pointers. The low E is thumbed from the previous bar, so can be used to play the middle E, leaving i,m,a to play the 3rd,2nd and top strings, respectively, (holding the whole chord of open E). Although I tend to use pinky a lot, so would use all four fingers, one for each of the top four strings. It's up to you - but I don't like idle fingers!
Start playing the arpeggiated chore before the barline, so that the top E sounds exactly on beat one of the bar it's written in. In other words, the roll starts earlier than it's written.


Does pouring dish detergent down a chipmunk hole get rid of them from my garden?

Question: I read that pouring dish detergent down an animal hole in the garden will cause the animal to leave the area. Does this work and does it kill the plants? I have a problem with chipmunks in a flower bed. Thank for your help
Answer: No it won't work.  Chipmunks are coming to your yard for any combination of food, shelter and water.
To block the hole wait till you see the chipmunk outside the hole and stuff chicken wire down it.
I have also used coyote or red fox urine which you can buy from hunting stores.  This only keeps them away for a while.
A better way is to remove what they are coming for.  Do you have a bird feeder or bulbs like tulips or lilies?
Consider using daffodils or fritillaria which are not normally eaten.
Comment: Chipmunks or any mammal wants to eat grubs, not roots.  Arghhh.  Kevinsky bringing up bird feeders is perfect.  You've made a few sweet mammals think your place is cool.  So what if they eat a few bulbs!
Comment: Thanks for your ideas! This is a great site. The chipmunks kind of scare me that's why I'd prefer they weren't in my flower boxes but they are only here for a short while. Not sure where they go afterwards.
Answer: Messing with burrow entrances doesn't work for a lot of burrowing animals, including chipmunks, because their burrows have multiple entrances.
Going from http://www.gardensalive.com/product/when-chipmunks-go-bad/you_bet_your_garden  it looks like commercial deer repellent is a good option.
Or you can make your own:

Puree 1 hot pepper and 1 clove of garlic into 1 pint of water
Strain with a cheesecloth (or rag or whatever)
Put the strained liquid into a spray bottle
Add one drop of dishwashing soap
Spray on plants you wish to protect from animals

As far as Dawn killing plants. There are conflicting stories but most are similar to mine: I've used very diluted Dawn on plants for other reasons and the plant was none the worse for wear (Dawn + water = excellent bug killer, btw - good for paper wasp nests).  But none of the things I've read, nor my experiences, are of the "soaking the ground in Dawn" caliber.

My recommendation: If their damage is purely aesthetic, try an owl or hawk statue. They're surprisingly effective.  Or, there's scent deterrents you can get (or make) to keep rodents away.
If they're nibbling on your plants: spray the plants with the mix.
If it's just because there's chipmunks afoot but they aren't actually messing with the look or plant matter - let them do their thing. It's a free tiny bit of tilling. (But then, chips in my yard don't really do anything but zip out, eat the cracked corn I put out for the doves, and zip back into their hole.)

I don't think dishwashing soap has an aggressive enough scent to deter them. Scent deterrents are ghastly when you smell them close. And my completely anecdotal evidence that dishwashing soap won't annoy them: I've had pet rats most of my life, for 20+ years I've cleaned their litter boxes with Dawn, and some of them just love camping out in the freshly scrubbed litter box.


What should I do after oak tree removal, before paving?

Question: I recently had a huge oak tree removed. It was ground to a stump. I'm going to pave that area soon.  Do I need to do anything to the area before paving? Someone told me to put salt in the soil.
Comment: Salting  the area is unnecessary and pointless, whether you're  wanting to pave or not - I'm rather curious as to why that 'someone' said to put salt down at all...
Comment: Salt would help kill the soil under the pavement, and prevent plants from growing. Generally, you need a lot of salt to kill vegetation... and keep roots from growing under the paved area. It's long lasting though.
Answer: Salt will not do anything to help you pave the area over.
I don't recommend paving the area at all unless you are willing to excavate at least a foot deep for four to six feet around where the tree was.  The reason is that there are still roots and part of the stump in the ground.  These will start to decompose and shrink in volume.  As this happens the gravel and asphalt above it will sink when weight is put on or water moves through.


What types of dragons are there in Middle-earth and how and why do they differ?

Question: What types of dragons are there in Middle-earth and how and why do they differ?
Comment: What research have you done to try to answer this yourself?
Comment: I recommend you flesh out your question a bit more in the body. This will not only attract more attention but will show you've thought about this question slightly more than it just popping into your head.
Comment: I'll edit it out.
Answer: There were Fire-drakes and Cold-drakes
The first fire-drake to issue from the gates of Angband was Glaurung; he was said to have sired the other fire-drakes and they are also the most common.

Again after a hundred years Glaurung, the first of the Urulóki, the fire-drakes of the North, issued from Angband's gates by night.
The Silmarillion

The only mention of cold-drakes that I could find was in the appendices of Return of the King:

At last Dáin I, together with Frór his second son, was slain at the doors of his hall by a great cold-drake.
Return of the King - Appendix A

Some of the Dragons were wing-less, such as Glaurung; these were often described as worms came in two types, the long-worms and were-worms:

"Of his son, Fram, they tell that he slew Scatha, the great dragon of Ered Mithrin, and the land had peace from the long-worms afterwards."
ibid

The only mention of were-worms comes in The Hobbit, and whether or not they actually are Dragons is questionable.

"Tell me what you want done, and I will try it, if I have to walk from here to the East of East and fight the wild Were-worms in the Last Desert."
The Hobbit - "An Unexpected Party"

This is everything I can think of right now, will come back and edit though

A drawing of Glaurung done by Tolkien
Comment: There's speculation that Long-Worms and Were-Worms were in fact one and the same thing, and that Hobbits just called Long-Worms by a different name, as they did so many things.
Comment: Though to counter my own argument, the Hobbit Trilogy movie (if you regard it as a legitimate source of information) actually depicts Were-Worms as their own, sort of giant Earthworm species, the great "Earth-Eaters" of old. No other source corroborates this, which is why there is speculation that Were-Worms either do not exist or were some other creature.
Comment: The etymology of were-worm, if modelled on were-wolf is "man-dragon"  (or mandrake? From Old English, "wer" means adult male.
Comment: What's your reasoning for understanding "worms" to refer just to the wingless ones?  There's lots of precedent in mythology for "worm" being used for winged dragons; and in Tolkien's *Farmer Giles of Ham*, the winged dragon Chrysophylax frequently gets referred to as a worm (and not just in insult by Giles).
Comment: Perhaps obvious to some, but I think the answer would be better if you explained what makes a dragon a "fire-drake" and what makes one a "cold-drake".
Comment: He forgot to draw the BRIDGE!!?!?
Answer: There were two general kinds, the Fire-drakes and Cold-drakes, as well as winged and unwinged dragons.
The first dragon encountered in the First Age was Glaurung.  Whether he was the father, in terms of breeding, or the first created is unclear.  Other fire-drakes are mentioned in the various battles of the First Age in The Silmarillion.  Glaurung is eventually slain by Túrin, but not before he created considerable mischief.  He was a speaking dragon.  It is unclear if all fire-drakes could speak.

Again after a hundred years Glaurung, the first of the Urulóki, the fire-drakes of the North, issued from Angband's gates by night.
The Silmarillion

During the last battle in The Silmarillion, when Morgoth was defeated by the intervention of the Valar into Middle-earth, Eärendil the Mariner with the Silmaril on his brow fought and defeated Ancalagon the Black, a winged dragon.  The battle took place in the sky.
In later ages other dragons are mentioned, though I can't find a reference for a dragon in the Second Age.
In the Third Age, a cold-drake slew a famous dwarven King, as noted in the first appendix of the Lord of the Rings (Return of the King).

At last Dáin I, together with Frór his second son, was slain at the doors of his hall by a great cold-drake.

A hero of the people who later became the Rohirrim slew a dragon.

Of his son, Fram, they tell that he slew Scatha, the great dragon of Ered Mithrin, and the land had peace from the long-worms afterwards."
Appendix A, Return of the King

In The Hobbit, Smaug the flying, fire-breathing dragon is eventually slain and his horde looted, although some years before he had destroyed both Dale and the dwarven kingdom in Erebor.  He is called "Smaug the Golden" by Bilbo at one point.
Gandalf, in The Lord of the Rings, mentions that of the seven rings of the dwarven kings, some were devoured by dragons but the details are sketchy regarding which ones and where.


Failure to unscale coefficients from a linear model with interactions

Question: I have data that require scaling fixed effects to fit linear mixed models with the lmer function from the lme4 package that converge. I want to unscale the estimated coefficients to present results in useful units. Previous posts address this issue, but I am unable to successfully unscale coefficients from models including categorical predictors and interaction terms. I used lmer() with my data set, but I have created an example using lm and the diamonds data for simplicity.
related threads:
    https://stackoverflow.com/questions/23642111/how-to-unscale-the-coefficients-from-an-lmer-model-fitted-with-a-scaled-respon
and
    https://stackoverflow.com/questions/24268031/unscale-and-uncenter-glmer-parameters
Below is some code that runs without error, but demonstrates that I can't get unscaling to work correctly:
library(ggplot2)
library(dplyr)

# function to rescale variables around 0
zscore <- function(x) (x - mean(x)) / sd(x)

# creates new dataframe with scaled values included
diamonds_s <- diamonds %>% select(carat, cut, price, depth) %>% mutate_each(funs(s = zscore(.)), -cut)

Create unscaled and scaled models
# Linear model with unscaled interaction specified
m1 <- lm(price ~ carat * depth * cut, data= diamonds_s)
b1<- coef(m1)
# summary(m1)

# Linear model with scaled interaction specified
m1s <- lm(price_s ~ carat_s * depth_s * cut, data= diamonds_s)
b1s <- coef(m1s)
# summary(m1s)

Function to rescale coefficients from answer by Ben Bolker
# https://stackoverflow.com/questions/24268031/unscale-and-uncenter-glmer-parameters

rescale.coefs <- function(beta,mu,sigma) {
    beta2 <- beta ## inherit names etc.
    beta2[-1] <- sigma[1]*beta[-1]/sigma[-1]
    beta2[1] <- sigma[1]*beta[1]+mu[1]-sum(beta2[-1]*mu[-1])
    beta2
}

Use model.matrix to get predictor variables
X <- model.matrix(price ~ carat * depth * cut, data= diamonds_s)

# matrix of response (m[1]) and predictor (m[-1]) means
m <- c(mean(diamonds_s$price), colMeans(X)[-1] )
 s <- c(sd(diamonds_s$price), apply(X, 2, sd)[-1] )

# or with unscaled response (not run because I scaled the response, price_s):
# m <- c(0, colMeans(X)[-1] )
# same for standard deviations
# s <- c(1, apply(X, 2, sd)[-1] )

Now attempt to unscale
b1r <- rescale.coefs(b1s, m, s)

The values obtained are wrong, however.
all.equal(b1, b1r, check.names=FALSE, tolerance=0.001)

I appreciate any input about this issue.
Answer: I think I had the same problem. I've solved scaling the interactions terms using their own means and standard deviations.
This thread may be useful, check the detailed Ben Bolker answer.