For questions on interpreting existing error messages that you have encountered, as well as writing and managing messages, assertions and checks for your own functions.

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47
votes
2answers
2k views

What are the best practices / most common / idiomatic ways to report errors in Mathematica?

In particular, what are the best ways to report errors about incorrect arguments to a function? Checking for the correct arguments is relatively easy using patterns, but how to report an informative ...
40
votes
2answers
2k views

Mathematica Debuggability

One of the things that I really dislike about Mathematica is its lack of debuggability compared to many other programming languages. Some of the problems arises from the functional nature of ...
28
votes
3answers
1k views

No warning when extrapolating with Plot

One of the most annoying "features" of Mathematica is that the Plot family does extrapolation on InterpolatingFunctions without ...
27
votes
1answer
457 views

which is better, using Assert[] or manual checks on arguments and other computations?

I never used Asserts in Mathematica, but trying to see what advantage they have over just argument check and additional definitions of the function to capture unwanted input. For example, which one ...
26
votes
4answers
2k views

Why does MatrixForm affect calculations?

This is a really newbie question, but it has me confused. Why does this code work without // MatrixForm and doesn't work with ...
20
votes
4answers
3k views

Importing a large Excel file

I'm trying to import a simple Excel file containing 94,000 rows and 52 columns of various types, mostly Reals. It's a 38-MB file. I get this super helpful error ...
16
votes
3answers
1k views

What is an “INTERNAL SELF-TEST ERROR”?

I got this all the time after updating to 9.0 (OS 10.8.2): That's Clipboard|c|3015 for the benefit of anyone searching. The error went away with 9.0.1, but a version has reappeared (multiple times ...
15
votes
2answers
315 views

MathKernel doesn't return all Messages

In Mathematica I run this command: Plot[Sin[x], {x, 1, 15}, GridLines -> error] It generates a Plot with this error message: A GridLines specification ...
15
votes
1answer
464 views

Quiet doesn't work with FindRoot when using Brent method

The following has no solution: FindRoot[x == 1, {x, 0.25, 0, 0.5}] And Mathematica correctly warns us: FindRoot::reged: The point {0.5} is at the edge of the ...
12
votes
4answers
410 views

How to catch complete error message information

If I evaluate this expression: Module[{}, 1/0;0^0]; msg = $MessageList I get: ...
12
votes
1answer
702 views

Finding a Specific Line in a Package

In a package I am developing, I accidentally left this line Protect[ uncompleted prior to running the package. Mathematica produced this error message ...
11
votes
4answers
2k views

What is the cleanest way to prevent divide-by-zero warnings?

If I evaluate {1, 2, 3, 4}/{5, 6, 0, 8}, obviously I get one warning: ...
11
votes
2answers
564 views

Take screenshot of the entire desktop using Mathematica

Is it possible to get a screenshot of the entire desktop directly in Mathematica? I am on Ubuntu running Mathematica 8. For some reason GUIScreenShot[] fails. But ...
11
votes
1answer
291 views

Check does not interrupt evaluation of the expression when a Message is emitted

On the surface, Check looks like a good method to use when you need to abort the evaluation of an expression whenever a Message ...
10
votes
3answers
4k views

General::ivar is not a valid variable when plotting - what actually causes this and how to avoid it?

I was just evaluating a couple of expressions and started to get errors like this: ...
10
votes
3answers
101 views

How to limit number of user-defined messages issued per evaluation

I have written code such that if it runs into a particular function, a warning message is issued. However, it is common for the program to call this function several times in a single evaluation, but ...
9
votes
2answers
2k views

Why is this semicolon in red?

I have a piece of code that works well, but when I put a semicolon after a plotting statement, the semicolon appears in red. What's the error?
9
votes
4answers
668 views

Using Position (which requires a pattern) in the same manner as Select (which requires a criterion)

I am using Mathematica7. I have a list of lists (creatively named list in the following sample code) containing data. I would like to find the positions of the ...
9
votes
2answers
335 views

Symbolic integration fails while numerical integration succeeds

I am hoping to evaluate the following integral Integrate[((r^3 - 7)^(2/3)*(1 - (r^3 - 7)^(2/3)/r^2))/r^3, {r, 2, Infinity}] but Mathematica informs me that this ...
9
votes
2answers
566 views

Solving/Reducing equations in $\mathbb{Z}/p\mathbb{Z}$

I was trying to find all the numbers $n$ for which $2^n=n\mod 10^k$ using Mathematica. My first try: Reduce[2^n == n, n, Modulus -> 100] However, I receive ...
9
votes
2answers
281 views

How to find a specific error message?

Is there a way to find an existing error message in the System` context, that is used for a certain case? I want to include a message in a custom function that ...
9
votes
1answer
187 views

StringMatchQ and Alternatives throws message in init.m

The report of this issue, which itself relates to code of my answer here, exposed a behavior I cannot explain. If I use StringMatchQ in combination with ...
9
votes
2answers
83 views

Detect Messages within an expression without losing the return value?

I know that Check[expr,failexpr] is a mechanism to catch messages. The problem with it is that if a message is generated within ...
9
votes
1answer
197 views

Can a System symbol spontaneously leak into a Global namespace?

During the development of a program to process bioinformatic data, I have encountered a peculiar shadow warning: Global...
9
votes
0answers
88 views

How to capture implicit fails in Plot or Show? [duplicate]

How can I make a construct similar to C++ functions: try{} catch{} I want to use it to avoid showing a lot of errors in the plot area when for example one of the ...
8
votes
2answers
1k views

What do I do when I get an “Iterator does not have appropriate bounds” error?

I used this as input Table[600851475143/i , {i, 1, 600851475143}] but got an error ...
8
votes
2answers
757 views

Table function with Part[] call misbehaving, but only after initial startup of Mathematica

I am getting errors like: Part::partd: Part specification standardBasis[[1]] is longer than depth of object. with the following Manipulate expression: ...
8
votes
1answer
246 views

Why is Dataset upset by division by zero?

Consider this example: ds = Dataset@Transpose[<|"a" -> {1, 2, 3, 4, 3, 2, 1}, "b" -> {6, 5, 4, 3, 2, 1, 0}|>, AllowedHeads -> All] Now say I ...
7
votes
2answers
253 views

Interpolating an Antiderivative

I'd like to be able to make InterpolatingFunctions for antiderivatives of functions that can't be integrated symbolically. However, the following code returns several error messages: ...
7
votes
2answers
235 views

How to switch off all messages?

How can I want to switch off all messages in a Mathematica session? Quiet[expr] allows me to evaluate expr without messages. ...
7
votes
2answers
146 views

Catching error in middle of evaluation of compiled function

I have programmed and Compileed a complicated numerical function. The function has singularities (i.e. are infinite) at certain input numerical values. I need to ...
7
votes
2answers
298 views

Adding a constant vector to a vector differential equation seems to break NDSolve. Why?

I'm trying to solve a differential equation that's phrased in terms of matrices and vectors. My minimum working example is this: ...
7
votes
1answer
133 views

What should I call the messages that appear when the mouse moves over failed graphics output?

I attempted to evaluate the following Plot[x^2, {x, 1, 2}, PlotStyle -> {RGBColor[a]}] which, of course, failed. After the failure, putting my mouse over the ...
6
votes
2answers
293 views

Using Read for calling external command does not release file handle

The standard and robust method for piping to/from external commands under Windows is to create a temporary file, save the input into it, pipe it to the command and save its output to a second file. ...
6
votes
2answers
496 views

How do I make NotebookEvaluate work inside Button?

The following creates a button to select a notebook to run. When the button is pressed it seems that Mathematica finds the notebook but cannot evaluate it. The following error occurs Could not ...
6
votes
2answers
91 views

Error when implementing StartProcess[] in loops (Do, While, Table)

I'm using Mathematica to control another program (Surface Evolver) through the terminal (ie using StartProcess[]; and ...
6
votes
3answers
178 views

Incompatibility of Row and TeXForm

Bug introduced in 9.0. persist as of 10.0.2 Update: Since no one has been able to give a reason for this change in behavior or provide a solution I am tagging this as a bug. Please report it to ...
6
votes
1answer
105 views

What is the simplest way to determine which call to a superfunction has generated a Message?

I have a complicated function which contains many calls to NIntegrate, NSolve, FindRoot and ...
6
votes
1answer
93 views

Error when putting ??symbol in a cell with another expression

Putting ??symbol in a cell and another expression in a different row of the cell returns the following error: ??symbol 1 + 2 ...
6
votes
1answer
386 views

What does MaxStepFraction do?

I find that with NDSolve[...] while solving a partial differential equation, changing the MaxStepFraction from ...
6
votes
1answer
350 views

Mathematica Opens Each Session With Beep

First off, I am using Mathematica 8.0 and Mac OS X 10.7.4. Recently, when starting a new Mathematica session, I am confronted with an error beep and message window stating "The file you tried to open ...
5
votes
4answers
121 views

Passing a variable messages list to Quiet

I'm trying to build a Verbose option into some code but I'm having trouble passing to a Quiet statement a variable list of which messages I want to suppress. My ...
5
votes
2answers
2k views

Error (NSolve::ifun) when using NSolve, I need help interpreting the error

I wrote the following code to observe how the solutions to the equation $(e^{i a})^2 = e^{i b}$ varied as $b$ varied between 0 and $2\pi$ ...
5
votes
1answer
1k views

FeynArts not working properly

So I have installed all FeynArts folders (from 3.5 to 3.7) with FeynCalc 8.0.1., and none of it is working properly :\ First I load the path to specific FeynArts package (3.5 for instance), then, by: ...
5
votes
3answers
344 views

ComplexInfinity/Indeterminate error when evaluating derivative

Motivation: I want to find the coefficients for the polynomial that is obtained when one adds together the first $n$ natural numbers to the power of $a$; that is, when you consider $1^{a} + 2^{a} + ...
5
votes
2answers
173 views

“Not a valid Filling specification” error

I have a function, which plots the given function array f. This is a part of the function: ...
5
votes
1answer
166 views

Sentiment analysis of tweets

I want to use Mathematica for a sentiment analysis on tweet-messages. For that purpose i selected several tweets. Each tweet is interpreted by myself as positive (pos) of negative (neg). For example: ...
5
votes
1answer
107 views

Strange Tilt on error notification

I was testing the source code of the answers to this question. And when I tried this response and maxed out most of the manipulators, this is what I got. What went wrong that the errors are ...
5
votes
1answer
200 views
5
votes
1answer
353 views

How to switch off messages on all kernels?

I am using ParallelMap for my code,however, it gives some messages that don't affect the evaluation process but fill up the memory and take some more time. So, I ...