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.

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2
votes
1answer
83 views

Local evaluation works, CloudDeploy did not work

I a playing around with my programming cloud account. What I have found, interactive functions often are not working because there are several details that are not implemented into the cloud. So I ...
2
votes
1answer
59 views

How to joint symbolic expressions together [duplicate]

I want to joint symbolic expressions together to create a another symbolic expressions. one way to do that is as follows: ...
2
votes
1answer
230 views

Transfer of symbols between contexts

As many others (I guess) I'm struggling with the handling of contexts within Mathematica. I'm working on a new package definition with the usual syntaxt specified by the Mathematica documentation: ...
2
votes
0answers
47 views

Syntax error in debug mode

Bug persists through 10.1 It appears that in debug mode, the \[Piecewise] symbol gives syntax error. Is it a bug? Are there ways to fix that except write it in ...
2
votes
2answers
82 views

Using Table with arbitrary number of variables [duplicate]

Let $P=\{p_1,...p_n\}$. I would like a way to implent Table[Expression,{$p_1$,lim},{$p_2$,lim},...,{$p_n$,lim}] where n and lim are parameters defined by the user. Any ideas?
2
votes
0answers
50 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 ...
2
votes
0answers
358 views

NonLinearModelFit with Two Dimensional List of Weights

I'm currently trying to fit Planck's law (B[λ, T]) to measurements, thereby determining Planck's constant. I have a list of triplets containing wavelength, ...
2
votes
0answers
336 views

Conditional statements in intial conditions?

This is potentially a daft question, but I thought I'd ask it; I have some material free to diffuse in a boundary between rn and ro; I've been able to get it working nicely for neumann type boundary ...
2
votes
0answers
201 views

Syntax colouring when using Symbolize

I need to use symbols with suffixes in order to make my code readable in relation to the Eurocodes. To do this I use Symbolize from the ...
1
vote
2answers
248 views

Finding the position of a specific value in a list

Is it possible to easily find the position of a specific value in a list? For example, if the list is {{x1,y1},{x2,y2},...,{xn,yn}} I would like to know the ...
1
vote
1answer
567 views

What does the slash-colon symbol do?

I came across a bit of code that uses the syntax /: and I don't know what it does. I can't find its documentation, or maybe I'm just not looking properly. The code ...
1
vote
4answers
367 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? ...
1
vote
2answers
67 views

What is the meaning of Range[10] /. {x_ /; PrimeQ[x] -> x^2}? [closed]

I'm currently doing a unit at university that touched briefly on Mathematica, but the final exam will feature multiple choice questions from Mathematica (along with excel and matlab). This leads to ...
1
vote
2answers
194 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 ...
1
vote
3answers
157 views

Equation values into list

Suppose I have a function say $f=x^2$. What I would like is a list (or even better, a list with a grid) which resembles {{1,1},{2,4},{3,9}, ...}. Ideally one should ...
1
vote
1answer
158 views

Differentiation w/o assiging concrete values

v = Subscript[v, 0]*Sin[(Pi*S)/Subscript[S, 0]]; a = dv/ds v; a = D[v, s] returns ...
1
vote
2answers
160 views

Shortcut for Range[]?

I use Range a lot. Is there any syntactic shortcut for it, or do you always have to spell it out?
1
vote
3answers
532 views

More than one expression in the Table[] command?

I would like to construct a Matrix using the Table[] command. The issue is that I would like to use more than one expression for it. What I need to obtain is something like this : ...
1
vote
1answer
444 views

Why is Euler's number an uppercase “E” and not a lowercase “e”?

Why is Euler's number an uppercase "E" and not a lowercase "e"? Isn't Euler's Number normally expressed with a lowercase "e"?
1
vote
2answers
635 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 ...
1
vote
2answers
560 views

Translating a “Point-to-Triangle” distance script from MATLAB to Mathematica

Update - Thanks everyone for your responses! After fixing a problem with vector normalization, the code below now works. I'm a new user, and I was attempting to port some Mathematica code from ...
1
vote
3answers
75 views

Form a matrix to have inequality elements

It looks like a silly question, but I could not find any answers online. Your help is greatly appreciated! Say I have two lists now. ...
1
vote
2answers
295 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 ...
1
vote
4answers
117 views

Help with writing a polynomial series [duplicate]

I want to write and evaluate an expression something like Sum[x[i] Product[y[j], {j(!=i), 1, n}], {i, 1, n}] but with correct syntax, where n is a any number ...
1
vote
1answer
128 views

Working of Date[]

Date[] returns the current date of local system, Date[1] returns {2012, 11, 15, 17, 41, 0.3161629}, ...
1
vote
1answer
72 views

How to make a StreamPlot with three variables and two expressions

I'm trying to make a StreamPlot in Mathematica with three variables. I already have two variables, x and y, that make an ellipse via StreamPlot[{-y,x}] but I ...
1
vote
1answer
299 views

Compile with array operations

When I use the function f with only the Module ...
1
vote
1answer
97 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: ...
1
vote
1answer
76 views

Why do two codes give different output?

I have tried the following to get the eigenvalues of several matrices of the type: ...
1
vote
1answer
96 views

How a novice user better understand the Q/A [duplicate]

A novice user reading Q/A here: I sometime need to just understand the syntax and meaning of commands exampled here. where is the best place to find it?
1
vote
1answer
113 views

Passing f[x][[1]] to FindRoot [duplicate]

FindRoot seems to fail for most examples of the form f[x_?NumericQ] := {x - 3 , x^3}; FindRoot[f[x][[1]], {x, 3}] ...
1
vote
2answers
79 views

Matrix with infinity on main diagonal

The question is trivial, however, there might be unexpected solutions. What would be nice way to create a square matrix with $\infty$ on main diagonal, and some arbitrary constant everywhere else? My ...
1
vote
1answer
55 views

NestList and RandomChoice from a list of functions

I am tryingg to modify Chaos Game Fractals from Wolfram Demonstrations. The part I am having problem with is this. Original code: ...
1
vote
2answers
152 views

MapThread with List Manupulation

I have the following three lists: ...
1
vote
1answer
221 views

Bincounting a list

I'm a Mathematica novice here. I'm trying to execute the following code to add random 1's into a zero matrix, repeat this many times, and then bin/histogram the number of nearest neighbor 1s. Can ...
1
vote
1answer
210 views

Can I use Table without the appropriate bounds?

I´d like to use the Table command without defining n, so that I can have a list of n ...
1
vote
1answer
77 views

How to evaluate sum with different coefficient in each term?

I would like to know if there is a syntax that allows me to enter a sum that has coefficients that vary for every term? I have no interest in evaluating them numerically, but rather to keep them as ...
1
vote
1answer
43 views

GCD of Table entries

This question is from a newbie, so please be gentle in thrashing if I'm missing something very basic. How can I use GCD on a matrix/vector entries stored as Table. For example, if ...
1
vote
1answer
46 views

Partial derivative of defined function with vector input

Background: Have written a formula for the refractive index for a glass slab (n) that depends on the variables t,a and d. Now I want to calculate for example some sort of error and I'll be needing to ...
1
vote
1answer
51 views

What is the correct idiom for mapping a 0 value in a modulo n expression back to n?

What is the correct idiom for mapping the $0$ value in a modulo $n$ expression back to $n$. For example if I want to be sure that any integer value maps back to the index for a character in the ...
1
vote
1answer
18 views

SetterBar Display using MatrixForm

I have vAwGOptns = { {{0}, {0}}, {{1}, {0}}, {{0}, {1}}, {{1}, {1}} }; and would like to select ...
1
vote
3answers
158 views

How can I make a summary of all the commands of Mathematica?

I would like to have a simple way to get summary information about all the many commands built into Mathematica. How could I do this? Is there a site I may refer to?
1
vote
1answer
60 views

Ways to protect certain parts of expressions

I am currently working on a quantum mechanics problem where I try to find equations that relate different states of a many-body system. The states are described by sets of pairs of integers, like ...
1
vote
2answers
56 views

How to get the outermost command evaluated first?

I have an expression like ToString[Stuff[...]]. I plan on having the Stuff[...] be manipulated as a string according to the output of other parts of the program. The problem is that Mathematica tries ...
1
vote
1answer
50 views

Correctly substituting a matrix into a scalar equation [duplicate]

I am having trouble correctly substituting a matrix into an (originally) scalar equation. For example: A = {{3, 1}, {1, 2}} cp = CharacteristicPolynomial[A, x] ...
1
vote
1answer
180 views

Correct usage of GeoPosition

My goal is to trace a ray down to the ground. I have done: ...
1
vote
1answer
230 views

Syntax error: newline character interpreted as multiplication

I'm getting this error in Wolfram Workbench, and I don't know where it comes from: "Syntax error: newline character interpreted as multiplication" This error happens around an If[] function, in a ...
1
vote
1answer
184 views

Remove failed Solve[] attempts

I can't figure how to replace a failed evaluation with a null value. I am very new to Mathematica. I have an equation that are being processed using the Solve[] ...
1
vote
1answer
55 views

Cannot use Part in Pure Function [duplicate]

I need to select some lists in the nested list of form of {{1,2,3},{2,3,4}}. I have used Select to complete my work. But when I tried Position, it doesn't work. For example, ...
1
vote
1answer
107 views

Trying to calculate derivatives of spherical harmonics

I am trying to confirm what is shown on this website: http://functions.wolfram.com/Polynomials/SphericalHarmonicY/20/01/01/0001/ But when I type ...