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Questions tagged [assignment]

For questions relating to assignments to symbols, patterns, or expressions.

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2
votes
1answer
22 views

SetDelayed error for Derivative rule

Having a delayed assignment of the form Derivative[1][f][x_] := HoldForm[f[x]] works. But if there is a delayed assignment for f as in ...
0
votes
0answers
22 views

Approximating the density of an arbitrary set using an arbitrary Folner Sequence of its superset [duplicate]

How do we use Programming to approximate this limit where is the density of in , is the Folner Sequence of , is an interval with , and . For more information, click on this link (replace G,X,i,g ...
8
votes
1answer
129 views

Error Message when nothing should be evaluated

When I try to define this simple function getCoeff[SeriesData[_, _, coeff_, _, _, _]] := coeff[[2]] I get an error: ...
1
vote
1answer
34 views

ContourPlot a list of equations generated by the Table command

The first command below produces proper contour lines while the second command produces an empty plot. I would think that the two commands should produce the same output. What's going on? ...
0
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0answers
26 views

Defining a function from an evaluated function stored in a variable

I have the evaluation of a function b, stored in appo. Now I want to define a new function f ...
0
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2answers
47 views

Monte Carlo Method [duplicate]

How do you use a Monte Carlo method to approximate the area enclosed by the circle.
2
votes
0answers
33 views

Mathematica: Remove argument from object with flat attribute

I have an object in mathematica with the attributes Flat and OneIdentity. I also defined the following substitutions: ...
3
votes
1answer
59 views

Combining `With`, `If` and SetDelayed

I just noticed that With[{x = 1}, If[x == 0, 0, 1]] returns 1 (as I expected) but ...
1
vote
1answer
40 views

Drop-down menu to globally change definition of a function `t[x]`?

If have a function t[x_] which is used extensively in a long notebook, but which has a variety of definitions, and which is used in a variety of ways. I'm looking ...
0
votes
2answers
28 views

How to select certain numbers to assign a new value and others still keep same

For an array TestA={15,12,5,8,6}, I want to change the value of number greater than 10 into 0, as TestB={0,0,5,8,6}. When using "Select" command, I will lose some numbers. Thanks.
1
vote
1answer
29 views

Vector shape and Dimensions

I think I have not understood clearly the difference between dimension and shape. I want to construct a vector remembering recurrence of the type : ...
2
votes
0answers
32 views

Programmatically Inject Logical Vector into Manipulate Checkboxes or Vice-Versa

I am building a large Manipulate application with about 50-60 checkboxes through which the user can select entities to be drawn on a main canvas. The main drawing routine, called from within ...
1
vote
2answers
60 views

Error in Assignment

I want to create a matrix with each element updated as per the formula, whose inputs are dependent on the location of element in the matrix. ...
1
vote
0answers
29 views

Un-assign MenuCommandKey

In my StyleSheet, I would like to assign to the environment Subchapter the Key Alt+2 (via MenuCommandKey. However, this is ...
1
vote
2answers
95 views

How to assign output of `Last@Reap` to a variable? [closed]

I would like to define a variable that equals the solution of a numerical equation. Usually something like smax=zmax/.FindRoot[Exp[-zmax/2]==2,{zmax,0}] would work. ...
1
vote
1answer
42 views

Why does it fail to assign values to variable in Grid? [closed]

I have a grid such as the following, and want to assign the values in the second row to the variable in the first row, but it always fail, can you provide a solution? Thank you! ...
0
votes
1answer
41 views

I am asserting a variable in Mathematica as Real yet it is not implementing it!

Element[\[Theta], Reals]; Ga = g; Gb = g*Exp[I*\[Theta]]; {{Conjugate[Gb], Ga}, {Ga, Gb}} I have a code as such for a matrix as given above. as ...
0
votes
0answers
35 views

Assign a Derivate to a new fuction variable

I'm having a new problem. I'm trying to create a new function from a Derivate of another function, but i'm can't getting it. Someone could help me? I'm thinking that is something in the syntax of the ...
1
vote
2answers
31 views

A question about a replacement of element of set

To begin with, I'm a poor English speaker, which means it would be hard to read to natives... I was trying to memorize mRNA codons with mathematica. ...
1
vote
1answer
65 views

How to use an up-value assignment when all symbols are “too deep”?

I would like to make an up-value assignment such as a/:Conjugate[a[x]]a[x]+Conjugate[b[x]]b[x] = 1 or ...
0
votes
1answer
56 views

Replace constant in summation function using replace or If or /

Hi i how do i replace constant for k in this summation. For following: Even 2*n Even replace k by a Even 2*n+1 Odd replace k by b Here is the code ...
1
vote
0answers
54 views

Making a function definition where the right hand side is evaluated before the definition is saved [closed]

My question is about assigning the resulting expression after evaluation of a function. So what I want: FOCf[x, y] := D[f[x, y], x] such it immediately ...
3
votes
2answers
141 views

Is it possible to set values for a list of variables using a for loop? [duplicate]

Let me preface this question by noting that this is a simple example meant to clarify what I am asking. The actual context in which I want to implement this involves associations containing hundreds ...
4
votes
2answers
138 views

Scoping of pattern variables [duplicate]

I have run into a problematic behavior, and then came to find that it is a "possible issue" called out in the documentation, but I guess I am just baffled that this IS an issue, and am wondering why. ...
-1
votes
1answer
61 views

Why it is doing part assignment? [closed]

I am writing an algorithm and need to keep updating an association called "verticesAssoc". My algorithm ran perfectly at first. However now I want to use the same algorithm on another association "...
0
votes
0answers
20 views

Seeing definitions of built-in functions [duplicate]

Possibly a very amateur question, so I'll apologise in advance. I'm reasonably new. I'm trying to write a Dot equivalent of ...
6
votes
1answer
64 views

unexpected result from augmented assignment to association

Is the last of these results expected? If so, how? ...
3
votes
2answers
176 views

Transferring DownValues

I have a code in which I define something like this: cc[1, 2] = 1; cc[2, 6] = 12; cc[3, 7] = 3; After some manipulation I define a sort of temporary variable ...
2
votes
1answer
81 views

Reassign a value to an array element

I have a very complex code in which I assign a value to an element of an array and then I reassign to it another one. A minimal example: ...
1
vote
1answer
65 views

Evaluating the 1st argument of Set

I want to assign a certain value to an element of a tensor. This element is identified by an array obtained from some evaluations, so we fix it. Here i present an oversimplified core part of my code: ...
1
vote
1answer
429 views

Tag Times in Null is Protected [closed]

I've some problems with the error mentioned in the title. Unfortunately, my code is full of subscripts so I'll show it in a photo. In this code the central aspect is to assign a scalar value to an ...
1
vote
3answers
186 views

Assign a function within a function [duplicate]

What I'm doing wrong? 1st function works as expected but the 2nd one doesn't. What I want is to enter an algebraic expression and two numeric constants and get the same result as with the first ...
1
vote
1answer
47 views

How to use a calculated expression on left-hand-side of an assignment?

Elementary question, I guess: I have a left-hand-side something like this: ...
0
votes
0answers
55 views

Trouble with UpSet(Delayed) and IgnoringInactive

I'm having problems setting an upvalue for a symbol that is supposed to ignore Inactive: IgnoringInactive[f[g[x]]] ^:= match; ...
0
votes
2answers
58 views

Hot to single out numeric values from NMaximize

I have some problem with NMaximize. The function NMaximize gives result like this NMaximize[f[x],x] {f[xmax] ,{x -> xmax}} I've read in various answers that ...
3
votes
1answer
89 views

assignments within Manipulate

I have encountered unexpected behaviour when assigning variables in Manipulate. Consider an inverted parabola y[x_, c_] := -x^2 + c The following code finds the ...
0
votes
1answer
64 views

Symbolic variable assignment

I looked around and didn't see this question on the forum, so my apologies in advance in case this has been answered here. My question can be concisely described by the following example: ...
1
vote
2answers
92 views

How to assign values using nested Part[ ] expressions?

Why doesn't this work? Can I make it work? ...
0
votes
2answers
108 views

How to 'unassign' variables used for PlotPoints, which subsequently print as e.g. Charting`Private`pvar$727158

I have a table of four insoluble equations, fceq, in terms of unassigned variables, Subscript[fc, i], Subscript[μ, i]. I am using contour plots to visualise ...
11
votes
2answers
1k views

Can't understand one paragraph in Power Programming with Mathematica

In the chapter 7 of the Power Programming with Mathematica, there is a paragraph discussing the behavior of Set- functions: (page 205. (pdf version p. 224)) ...
0
votes
1answer
34 views

Assigning eigenkets to particular eigenspace depending on eigenvalues of system inside a module

I am writing a module, in which the Observable and State is given, so I need to write a function/module QuantumMeasurement, that will return a state of the quantum system resulting from the ...
0
votes
0answers
42 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], ...
1
vote
2answers
57 views

Assigning variables whilst in a context

When working in a context, I would like all variable assignments to happen on symbols in the new context. This doesn't normally happen. For example, ...
5
votes
2answers
149 views

How to set parts of Associations “named with” SubValues

Parts of Associations can be set with the following syntax: as = <|"a" -> 10|> <|"a" -> 10|> as["b"] = 20; as ...
2
votes
0answers
55 views

Writing a variable to file with its value, not its name [closed]

This is my first time ever posting a question about Mathematica anywhere, so please excuse my ignorance. I'm trying to save a ColorFunction to file, but can't get the variables to be written as ...
2
votes
1answer
114 views

Generalization of the probability of union

hi How can I do for mathematics to expand this equation for any value of the variables i, j, k
3
votes
0answers
469 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: ...
2
votes
0answers
65 views

Matrix as function manipulation

Consider matrix mat[x_] := {{1, 2}, {3, x}} with mat[x][[1]] giving {1, 2} I wanna ...
11
votes
2answers
3k views

How to pass variables by reference and by value [duplicate]

I haven't seen this question specifically addressed before in this site, although some hints and traces have been given, for instance, here: Pass by reference for an option argument Does pass-by-...
5
votes
1answer
71 views

Set on symbol with OwnValues skips UpValues

Can anyone provide insight on what's going on here? First I define a new Set behavior for a symbol: ...