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Questions on the use or manipulation of Mathematica variables (i.e. names associated with a changeable value). Use [variable-definitions] or [assignment] for questions on variable context localization, or assignment.

1
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2answers
38 views

Showing variable values on a 3D Plot

I am running a 3D plot a 100 times to show the dynamics of two undetermined variables (cM and cR) for a 100 values of ...
0
votes
1answer
21 views

Extract and name PNG's from loops [duplicate]

I want to extract PNG files and name them depending on the dummy variable of a loop. For example, starting from ...
0
votes
0answers
28 views

matrix perturbation general formula with random values

Is there a way to generate an arbitrary-sized diagonal matrix of variables, not numbers, in mathematica? Probably unnecessary context: For a research question I'm pursuing, I want to find general ...
0
votes
1answer
31 views

Use Solve for two Functions to find 1 common Variable

I have 2 functions that look like this: F[t_,d_]:= 10+t+2d G[t_,d_]:= 5+t+d I'd like to solve this in such a way to know for which t both Function have the Same value. I assume that this won't be ...
17
votes
2answers
301 views

When to name a variable with $

There are some symbols in the Wolfram Language that start with $, including $Abort, ...
1
vote
1answer
41 views

Mathematica is picking up variable definition from other files

Mathematica is using definitions from other open files in the same folder. I want variables not defined in a particular file to be treated as undefined variables. I do not want Mathematica to pick ...
0
votes
0answers
25 views

What's “expr”, “opts”, “s”, “uspec” in Names[“Global`*”]

SYSTEM: Win7 SP1 X64 Eng - MMA X64 On a very random occasion, I did something and some undesired result came up. So I checked Names["Global*"]`. All I had ...
0
votes
0answers
24 views

Problem in importing function in NDSolveValue

I have a code for solving a system of 2 differential equations (sol1). Given that what's inside is a bit heavy, I define functions so that I can call them. My issue is that when I write everything ...
2
votes
2answers
74 views

Define a function of a function of an arbitrary variable

I want to define a function called int that takes another function as an argument and yields an integral of that function from 0 to 1 (just for example). So I ...
0
votes
1answer
26 views

Plot interpolating function depending on free variable inside manipulate

I create an interpolating function which depends on some free variables. I then want to plot it inside a manipulate, but my output is empty. What am I doing wrong? ...
0
votes
1answer
32 views

Altering the Values of Global Lists Within Tables

Say I have some lists: list1 = {4} list2 = {2} list3 = {6} list4 = {9} list5 = {7}. I want to alter them in a table like so: ...
0
votes
1answer
37 views

Solve an equation with two specific domains?

In Solve an equation with specific domain? I asked how to write a code in Mathematica with one specific domain for one of its variables. Now I have a questions: If two of the variables are from ...
1
vote
2answers
53 views

Solve an equation with specific domain?

How can I write a code in Mathematica to solve an equation with variable in specific domains? For instance, I want to write a code for ...
-1
votes
2answers
66 views

How to replace Variable With Variable [closed]

Clear[a, b, c]; a = c; a =. ; b = a; b =.; c = b; c =.; Print[a, b] and the result is {a b} but I want the result ...
0
votes
1answer
64 views

Automatic variable naming

I am trying to construct a complicated code in which I need to name a lot of variables and their definitions. For Example: The problem is as follow: Once I insert new variable in between two, I ...
1
vote
1answer
44 views

Using Variables[] as the argument of Plot[]

I want to use the Variables[] function to extract the name of the variable of a function, such that I can use it later, e.g. in a ...
0
votes
1answer
45 views

How to plot solutions for simultaneous equations

I have 2 simultaneous equation of $x$ and $y$. Here is how I solve it, and it works. But I want to vary the parameters n and ...
2
votes
1answer
62 views

Relabeling and matching variables (in MultiplicationTable)

Suppose we have a set of data given here as the multiplication table of 8 elements labeled {1,2,3,4,9,10,11,12}: $$ \begin{array}{cccccccc} 1 & 2 & 3 & 4 & 9 & 10 & 11 & ...
1
vote
1answer
51 views

Use Manipulate for a global variable

I do have a global variable called w1, which is used as a factor in a dataset, however I want to make this factor dynamic. ...
0
votes
1answer
45 views

How can I evaluate a function using the results of Reduce?

Can I use the output of reduce to define a variable in a function definition? In other words, can I somehow skip the step where I manually enter t:=2? ...
0
votes
0answers
29 views

assigning numerical values to variable

I have a csv data file, has two columns of data. First column denotes time (t) and the corresponding value in the second column is flow rate (f). I would like to assign these values to an array f[t], ...
0
votes
0answers
72 views

What are the valid symbol names for packages?

Regarding to the message: ...
1
vote
0answers
42 views

Execute a notebook with a changing variable

I have created a notebook with one fix variable that I want to run from 1 to 100. Every time the whole notebook (all cells) shall be executed for the given number. At the end of the notebook, it shall ...
0
votes
1answer
56 views

Issue with variable recognition

Why are the variables r,s,u,v identified differently in the definitions of F2,G1,G2?
1
vote
1answer
48 views

How to evaluate user-defined functions with variables?

I have an extremely simple question, but I couldn't find anything anywhere, maybe I didn't know what to search for, so feel free to mark it as duplicate if there is a duplicate. Let's say that I ...
0
votes
1answer
41 views

Create an array of independent variables of variable size, all dependent upon the same dependent variable

I have an array of variables that I've constructed, that all depend on time s ...
0
votes
2answers
43 views

How can I create a row matrices of large dimension by a code? [closed]

I am trying to figure out how to create a function that can create the row matrix pattern below. co = {{a1, a2, a3, a4, a5, a6, ...., a100}};
3
votes
0answers
109 views

Multiple variable assignment from a list

For example in Python, if we have a list of 3 elements, say ls = [1,2,3] and we want to assign a variable to each value (from left to right), one can do as follows: ...
0
votes
0answers
14 views

Variables in AskFunction

I'm trying to ask people for certain variables by using the AskFunction code as follows: ...
3
votes
2answers
94 views

Combining Multiple Lists

Let's say I have 4 lists: list1 = {a,b,c,d}; list2 = {e,f,g,h}; list3 = {i,j,k,l}; list4 = {m,n,o,p}; I can combine them using Join ...
0
votes
0answers
69 views

Is there in Mathematica something like class in Java or struct in C? [duplicate]

I am new to Mathematica and I am very impressed with its features. Although I don't understand how to do a simple thing: for example, I want to create few point variables (say a,b,c,d,e), each storing ...
0
votes
0answers
33 views

The conditions used in Sum or ParallelSum: Calling a function/variable

For some reason, I encounter a problem when doing the Sum and ParallelSum (or doing the Do or ParallelDo, e.g. such as the issue here), I figured that the potential cause of the problem can be ...
0
votes
0answers
19 views

Write vector with variables and calculate its norm in terms of the variables [duplicate]

I have a vector v defined as follows: v[x_] = {0.5, 0., x} I calculate its norm, and expect for it to be ...
0
votes
1answer
50 views

Solving an equation of two variables by looping over different values for one variable [closed]

I have a function: f[x_,y_]=x+y. I would like to loop over some values of x, and solve for y ...
1
vote
1answer
39 views

Numerically solving a system of three nonlinear equations by predefining functions [closed]

I have three functions of three variables, f1(x,y,z),f2(x,y,z), and f3(x,y,z), and I'm ...
6
votes
1answer
176 views

Tremendous bug using EstimatedDistribution (using NMinimize) in v8.0 and v10.2

Let's define F4 and estimate the distribution of the data: ...
1
vote
3answers
122 views

How to extract variables with time subscript and their coefficients

I have a expression of the following form: $$x_{t}=a_{0}+a_{1}x_{t-1}+a_{2}y_{t-2}$$ where $a$'s are just coefficients and anything with time subscript is a variable. I would like to have list of ...
0
votes
0answers
43 views

to reduce the unknowns of a set of equations with several symbolic coefficients, e.g. using the GroebnerBasis

I have a set of $4$ equations with $4$ unknowns $\theta_1$ to $\theta_4$, and would like to eliminate the number of unknowns, to get a smaller set of equations, e.g. $n$ equations with $n$ unknowns, ...
0
votes
0answers
144 views

Extract fit error from parameter table to use as a variable

Is there anyway to extract the fit error and store it in a variable. I have done something similar to use actual fit results as ...
0
votes
0answers
29 views

function restorage problem [duplicate]

Code below f[1, 1] = 1; f[1, 2] = 2; f[1] = Min[f[1, 1], f[1, 2]] Outputs 1 However, the desired output is ...
0
votes
1answer
37 views

Taking variables from string

In a mathematica operation I am getting the o/p say, 1->2. For the next step, I want to use these two numbers as variables, say take them as 1 = m and 2 = n. How can I do it.
1
vote
2answers
79 views

variable dimension table

(A very simplified version of my code:) How can I create a Table[] with a variable number of dimensions, e.g.: ...
1
vote
2answers
84 views

How to transform a series of scalar variables to a vector variable? [closed]

Say a function is set: a := Sum[b[i], {i, 8}] As can be seen that b[i] is a scalar variable. Now I want to transform the ...
2
votes
1answer
69 views

How to form list of all OwnValues of symbols in Global context? [duplicate]

How do I get the list of all OwnValues of symbols in the Global` context? All my attempts have failed because ...
2
votes
3answers
144 views

Assign an array of numbers to an array of variables

I have a huge array of variables like this. ...
2
votes
2answers
87 views

Treat 2 variable as 1

Is there anyway to treat two variable, that are a result of expansion, as one? To use Solve[] I can do ...
2
votes
3answers
161 views

Pure function within another function

I am writing a function along the lines of the following: func[basis_,coordinates_,vars_]:=Table[Function[vars,monomial]@@@coordinates,{monomial,basis}] The idea ...
0
votes
1answer
64 views

Solve trigonometric expression

Mathematica is not able to solve this expression : $Solve[ 2 e == h + r * sin[theta - q ] + b* sin [theta ] + e*cos[theta ] , theta]$ Solve::nsmet: This system cannot be solved with the methods ...
0
votes
1answer
141 views

Is it possible in mathematica to use dynamic names of variables [duplicate]

I have variables in my code following the following notation : theta12, theta13, theta14 etc.. I would check the values of all this variable so I could write an if condition for each theta but I ...
2
votes
0answers
44 views

Variable assignment/replacement issues

I have three questions about variable assignment. Module[{z}, z = y; p'[y] /. p -> Function[y, Evaluate[z]]] When I run the above code, it outputs 0. 1) If I ...