Questions on assigning and unassigning definitions to names that represent them, including issues raised by context and localization. Use tag [assignment] for issues relating to Set versus SetDelayed.

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0
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3answers
112 views

Identifying the symbol which has a specific value

I'm writing a program that will solve the value of 1 variable in a 4-variable equality equation, but the variable to be solved will depend on the user's input to the program. This is what I've come ...
0
votes
2answers
159 views

setting real parameters in Hamiltonian matrix

The following Matrix represents my Hamiltonian. m = {{ B/2 - d - j/2 + a, (Sqrt[2]*j)/2, M}, {(Sqrt[2]*j)/2, B/2 + a, 0}, {M, 0, (-3*B)/2 - d + j/2 + a} How can ...
0
votes
1answer
77 views

Collecting variables from Subscript

I have followings set: t = Transpose[{x[#] & /@ Range[20], RandomInteger[15, 20]}]; Subscript[#[[1]], #[[2]]] & /@ t The code is just to build my set.So ...
0
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0answers
70 views

Numerical Integration/Function

I have a problem with a function defined numerically through an integral of the form: ...
0
votes
1answer
41 views

How to assign the array data to variables?

A very basic question but puzzled me for long time on how to assign array to variables. For instance, we have array {{t1,x1},{t2,x2}...{tn,xn}} how to assign the first element to variable t and ...
0
votes
0answers
9 views

Watching variables during Notebook work session [duplicate]

One feature that I have always wanted but could not find out if it was supported and that is to actively watch variables and their values while working in a Notebook session. In fact, there are two ...
0
votes
1answer
26 views

Variable as Difference of 2 Variables

I would like to evaluate a function based on the absolute difference of two variables. An example: g=5*x-5*x*y-5*y diff=x-y D[g,x] D[g,y] D[g,diff] I cannot find ...
0
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0answers
18 views

SharedVariable in WebMathematica

How can I create a variable to be used and setted over all my WebMathematica kernels? Here is the case: Create a package with do data structure like: data = ...
0
votes
0answers
39 views

Replacing variable names in a notebook

I am working on a code that simply imports and graphs a function. If I preset the directory I would have something that looks like this: ...
0
votes
1answer
36 views

Reducing Output length by introducing new variables [duplicate]

I have outputs like "expression/(1+3*c^2) +anotherexpression/(1+3*c^2)" and so on. Is there any way to set 1/(1+3*c^2)=A where A is a new variable so that the output reads like ...
0
votes
0answers
52 views

Coupled ODEs with boundary conditions - DSolve Error

I'm relatively new to mathematica and I can't find the error here. I suspect it has something to do with the fact that vx, vy, vz aren't blue on my mathematica - as in, they already have some assigned ...
0
votes
0answers
36 views

Can the value of a variable be made to persist between front end sessions? [duplicate]

For example, say I create a notebook with a cell a = 5 + 2 and then I close Mathematica, reopen the notebook, enter a new cell ...
0
votes
0answers
29 views

Get value for a variable from user inside a module [duplicate]

I am writing a module. When I run the module, I want it to ask for a variable, like I can in other programing languages such as C++ or Python. For example, in C++: ...
0
votes
0answers
89 views

Is there a better way of creating/assigning variables programmatically than using strings and ToExpression?

For quite a while now I've been wondering how to assign variables programmatically, and I have finally figured out one way of doing this. For example in a game where you have a variable number of ...
0
votes
0answers
31 views

How to change $n$ variables with $n$ Buttons automatically [duplicate]

I was trying to make a little game, and I came accross this problem. The goal is simple. There are going to be $n$ number of buttons, and each one will change a value of one variable. For example, ...
0
votes
0answers
56 views

How to hide global variables in package?

in the package I'm writing I have a list of global variables which should not be visible from a notebook. Here's an extract of the package: ...
0
votes
0answers
35 views

Block, With, Module, can anyone help me understand the distinction? [duplicate]

I've been working heavily with Block[] for months in my research so I've read the documentation for the seemingly similar commands With[], Block[], and Module[]. Personally, I've had by far the ...
0
votes
0answers
96 views

Local variable names - Is there an easy way?

I apologize first, because this has been asked, like in Treat all variables as local in a module [duplicate] Variable scope similar to other languages But I don't get how to use them. Some codes ...
0
votes
0answers
36 views

Varying number of function arguments [duplicate]

I have a function of six arguments: ffit[q1_, q2_, q3_, q4_, q5_, q6_] := (a1*q1^2 + a2*q2^2 + a3*q3^2 + a4*q4^2 + a5*q5^2 + a6*q6^2) ...
0
votes
0answers
112 views

NIntegrate with an arbitrary number of variables [duplicate]

I need to evaluate NIntegrate with a variable number of variables. Here's a concrete example. I'll accept an answer that finds a way to make the example work. I ...
0
votes
0answers
37 views

Subscripts to a variable; why a letter shoud come before a digit?

I noticed that I cannot create a variable $f_{2s}$ since Mathematica seems to leave a space between the subscripts 2 and s ...
0
votes
0answers
127 views

How to define a variable as a function of another variable?

I want to define a variable q which is a function of t. And I want to define another variable ...
0
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0answers
33 views

How to define a vector of arbitary length [duplicate]

I need to use a vector of length which I can change, indexed symbolically So for e.g. when N=3 I'd like to have vec={c1,c2,c3} when N=5 ...
0
votes
0answers
68 views

What's the best practice for nested local constants? [duplicate]

Possible Duplicate: How to avoid nested With[]? I have many situations where I have a constant that is local to a function, with other constants that are computed from it. I see that I can ...
-1
votes
0answers
27 views

Can a polynomial have -1 as a power? [on hold]

Based on the definition of a polynomial. Can a polynomial for example be something like this and have a negative one as one of its powers? 3x + 3 + 3x^(-1)
-2
votes
2answers
208 views

Mathematica not assigning variable correctly

So I have been fiddling with this the last hour and I just can't get it to work. I have 3 matrices of the same size which contain nothing but 0's in a list, I also have 3 matrices of the same size ...
-4
votes
2answers
84 views

Module function corrupts string? [closed]

I have the module who should replace some elements of a matrix with checkboxes ...