# Tagged Questions

Questions on correct (or improved) formulation of Mathematica code to achieve particular results. Use this tag (not "symbol") for questions about all those odd @@ /@ # & and ~ characters.

61 views

### Why is Cell > Convert To > InputForm not invertible?

I sometimes post code to PhysicsSE, and I usually convert it to InputForm first before posting, in order to avoid pages and pages of ...
98 views

### Half kth term if n is even and k=n/2?

I am trying to write a function which will perform the equation in the attached image. So far, I have: ...
2k views

### How does one specify Neumann conditions for NDSolve?

I have a series of functions defined in my notebook, and then want to use this to solve a diffusion-reaction type equation. At the moment, something like this works: ...
436 views

### Do any mainstream text editors support Wolfram Language syntax for highlighting? [duplicate]

Syntax Highlighting for Mathematica on a Blog There is the above, but I'm not terribly excited to install rogue packages. For example on github, I share lots of Mathematica code. I see no way to ...
154 views

### Meaning of backtick in conjunction with units [duplicate]

In this fragment from an equation solution the backtick is used twice: ...
2k views

### Meaning of backtick in floating-point literal

If I compute, say, 1/3//N, Mathematica displays 0.333333 as the result. When I copy that output to use elsewhere, the paste ...
436 views

### How to plot a region bounded by three equations?

I'm very new to this website. I am having trouble plotting a 3 dimensional region bounded by these equations: ...
197 views

### How to select only NotebookObjects that are referring to ordinary notebooks? (not palettes etc.)

There is of course function Notebooks[] But, unfortunatelly it hasn't got useful options in this context. My question is how to pick ...
188 views

### Replacing a function in defined expressions

I'm having a little trouble with substituting functions into an expression. A minimal example is as follows: ...
407 views

### How can I avoid getting the error message Goto::nolabel in my code?

If anyone could suggest a reason why Label[begin] ... Goto[begin] would return Hold[Goto[Begin]], and (better) how can I avoid ...
245 views

### Issue with Compile

The following code works fine with the the function f defined as a module, however, when I convert it to be a compiled function, it gives me errors. Can some one ...
391 views

### Compile with array operations

When I use the function f with only the Module ...
94 views

### Determining whether or not an expression is an integer

I'd like to define a function that controls if a certain number is an integer, rational, algebraic and so far. First, I tried generating a list of those numbers: ...
117 views

### A question about two ways to use Default

Usually we define a function with default values by the syntax x_:default, but there is another technique to do this by registering a global default value with <...
161 views

I have the following three lists: ...
113 views

### How to input pure function to package?

I would like to input a pure function into a custom written package, but am running into a variety of errors. The package I have created is as follows: ...
2k views

### How to evaluate Modules in a notebook from another notebook?

I would like to create a notebook populated with several modules and be able to evaluate these modules by running a separate notebook. I have attempted several uses of the ...
177 views

### Normalize equation in NDSolve?

I have numerically solved and plotted the solution to the Mathieu equation using NDSolve successfully, as below: ...
791 views

### How to create custom Graphics primitive?

How to create custom Graphics primitive? It should have the following properties, resembling properties of built-in geometric figures, like ...
100 views

### Why there is no SlotSequence (##) form analogical to #[[ ;; n]]

I'm aware that this may be closed as offtopic but there are people around with "offtopic" knowledge :) So, in List context we can: ...
104 views

### Convert variable into function

Sorry if this is a duplicate, but I have a variable called H. H is some complicated function of ...
116 views

### MapThread over a nested list

This may be a simple question. Please close it if it is already answered. I have a nested list kr = {{35, 32, 27, 20}, {36, 33, 28, 21}, {37, 34, 29, 22}} I ...
95 views

### Square root of a value defined in a finite field?

I am trying to find the right way to compute the square root of a number defined in a finite field. For example, ...
614 views

### Finding a number which has the same remainder when dividing certain other numbers

I am having some trouble with formulating my problem in Mathematica for this question: Is there a number greater than 1 which leaves the same remainder when it divides into 1716, 2154, and 4271? (...
110 views

### How to programmatically comment out multiple source files?

How to programmatically comment out the entire content of multiple .m source files assuming they start with correct Mathematica syntax? I need it to be robust so ...
197 views

### Please explain this code (contains Append, Do, Coefficient)

I am a graduate student using a past student's Mathematica program. Will someone please explain to me exactly what this piece of code is doing? Specifically the ...
47 views

### Using Table[ ] vs using Do[Append [ ] ] [duplicate]

Is it generally better/faster to use the Table function over using Do[Append []]? For example, I have this piece of code: <...
306 views

### How to define the irrational domain or any other arbitrary domain?

I have found no way to define the domain of Irrational numbers. I can easily define a test to see if a number is irrational by defining: ...
80 views

### How to write series of Do[ ]'s with a single Table[ ]?

Edited to provide more information (sorry I don't know how to format matrices here) I would like to replace: m = 4; ...
194 views

### Why is my answer being displayed with “Subscript^(0,1)[a,b]”? [duplicate]

I type in my equations using ctrl+- to make it look nice and my answer outputs in "Subscript^(0,1)[a,b]" form? What is going on? In the answer some bits are displayed with the actual subscripts and ...
152 views

### Differentiating a Dot Product

I apologize if this type of question has been asked before, but a preliminary search turned up nothing. I would like to differentiate dot products. For example, consider taking a derivative with ...
144 views

### How to display output as symbols?

I have this piece of code which populates a matrix following different rules depending on row and column number: ...
110 views

### Why is ^^ff not the same as ^^ToExpression[“ff”]?

I want to convert a hexadecimal string to a decimal (base 10) number: 16^^ff 16^^ToExpression["ff"] The 1st line returns the correct answer of 255, while the 2nd ...
161 views

### Holding Input Windows

I am creating a Mathematica document which contains a list of proofs in various fields of Mathematics so that I can easily review whenever I would like. First, I create a large set I call 'proofs' ...
454 views

### Looping with NDSolve?

I have a series of PDE equations that are solved with NDSolve for certain variables $a$ and $b$ - Now, I want to see the output at a time $t$ as $a$ and $b$ change; so I was thinking of a loop ...
130 views

### Return only one numeric solution to equation [duplicate]

Consider a simple plane equation 2x-3y+4z==7 I just want some position vector on that plane. For example, {7/2,0,0} would be ...
4k views

### How to reverse the direction of the y axes

I have a similar question to this one. Unfortunately, the answers there didn't help me. I would like to plot a simple function with the normal Plot function. ...
99 views

### Dot when used in a pattern becomes Times… Why?

In[1] := Hold[a.b] // FullForm Out[1] := Hold[Dot[a,b]] So far so good. ...
23 views

### Incorporating Built-In Function Options/Parameters into Shorthand [duplicate]

Shorthand syntax provides an alternate way to apply functions and, in many cases, improves readability. A simple example would be ...
465 views

### Conditional range in a parametric plot

I have a program that needs to be done like this: ParametricPlot[ equation, If[x < 1, {x, 0, t}, {x, t, 2}]] But Mathematica didn't seem to recognize the ...
203 views

### How can I define a ⊕ operator?

What is wrong with the following code? CirclePlus := SparseArray[Band[{1, 1}] -> {##}] & a_ ⊕ b_ := CirclePlus[a, b] SetDelayed::write: Tag Function in ...
69 views

### Pathological behaviour when evaluating a sum

When I declare the function $f$ as follows: f[n_] := Sum[x/Sum[Sqrt[y], {y, 1, x}], {x, 1, n}]/n the input ...
204 views

### Making nice code: choosing one of several procedures

Happy new year mathematica gurus of stack exchange! As I see it one of the major obstacles in getting decent at programming mathematica is that, not only do you need to learn how certain commands ...
115 views

### Why can Format be used on the left side?

I am learning Mathematica in random order by reading its documentation. This approach is what I like most when learning new things. Consider the following 2 cases. Syntax A: ...
146 views

### Why does the iterator index in Table not work here?

I type the following command line Table[D[#1,varx[[i]]] &,{i,3}] where varx is a vector of dummy variables ...
239 views

### What are the min and max arguments to EdgeDetect?

What are the min and max arguments to EdgeDetect, for all methods and specifically "Sobel"? How do I find the limits or ranges ...
373 views

### Changing Default Color for Titles, Sections, Subsections, etc., and Items (bullet color) [duplicate]

I'm new to Mathematica 9, and I assume there must be an easy fix for my problem, but I have not been able to find any yet. Essentially, I want the default color for the text of all of my titles, ...
411 views

### Is it possible to insert arguments into functions when they're used like Function@ or //Function?

Is it possible to insert arguments into functions when they're used like Function@ or //Function? Sometimes I need to do this, but then I have to return to the standard function usage: Function[] ...