Questions tagged [evaluation]

Questions about how Mathematica evaluates expressions, tracing evaluation (Trace*), handling expressions in unevaluated form (Hold*, Unevaluated), nonstandard evaluation, etc.

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2
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2answers
177 views

Wolfram modules returning functions

I am trying to get a With / Module pair to return a set of functions. ...
1
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0answers
84 views

Do Loop contained in a function defined within a custom package doesn’t work as expected but works fine when function is defined directly in a script

Below is my code and I am having problems running the StdMPC function that I am trying to define. Running my code gives me the error that the matrix A and Xopt[[i]] are not of compatible shapes for ...
5
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1answer
142 views

Integral of a function defined with a loop

I have defined a function g as ...
0
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1answer
46 views

How to instruct internal function to evaluate arguments only after numerical values are plugged in?

For convenience, let me start with a simple example. The following code calculates the sorted eigenvalues of a 4x4 Hermitian matrix with a parameter x ...
1
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1answer
51 views

function within function

delFunc[funcform_, lstofparams_,lstoferrs_] := √Total[Table[(D[funcform, lstofparams[[i]]]*lstoferrs[[i]])^2, {i,Length[lstofparams]}]] ...
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0answers
33 views

Simplifying expression involving Boson operators

I want to do calculations involving Boson operators $a(k), a^{\dagger}(k)$, e.g $(x + a(k))(y+a^{\dagger}(k))$. My code is: ...
3
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1answer
47 views

How to force Mathematica to output a function using its alternate pretty form when using Apply? [closed]

By default, Bra is an undefined function. Let's say I have defined Bra, Bra[a___]:=... such ...
0
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1answer
43 views

Symbolic evaluation expressions containing a user-defined function [closed]

I have a function F[r] = (-1)^(r + 1) Binomial[n, r]/r I would like to evaluate F[x+1]/F[x] for some arbitrary ...
3
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2answers
123 views

Change the color of sub-expression when the whole expression evaluates to a different expression

I found it's tricky to colorize a sub-expression of an expression that changes to a different expression when it is evaluated. For example, if I replace s with ...
1
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2answers
72 views

Repeat every $ x $ coordinate except the last one

Below is the code to print the x value. ...
2
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2answers
62 views

Print function value at specified coordinate

Below is the code to evaluate the function. I am trying to print the function values at a specified coordinate as shown in ActCoor. ...
0
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1answer
54 views

Mathematica 12.1 is treating all my cells as raw texts by default

I was once using Mathematica 11 it all works fine - when I create new Notebook (.nb) input like 1+1 and press shift+...
1
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1answer
44 views

How to inline a variable in function definition

I need to compile a function g that calls an external function f. f and ...
0
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1answer
185 views

Elliptical Integration

I have an integral which can be decomposed into three complete elliptical integrals. I want to know the method by which I can achieve this. The integration is the following: (4 (-1 + y)^2)/(c Sqrt[y (-...
0
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1answer
71 views

Evaluate analytic solution of the function [closed]

Here, i have plotted a function and i would like to print the y coordinate values from the plot for the x-coordinate given below. Coordinates in the sequence that every fourth y-coordinate should be ...
2
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1answer
29 views

How to conveniently evaluate a function at several points when there are way too many points

Say I define a function as follows: pos[n_] := If[Cos[288 ((n Pi)/233)] > 0 && Sin[288 ((n Pi)/233)] > 0, 1, 0] Then I want to evaluate at this ...
6
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0answers
98 views

Difference between the infinite rewriting behavior of evaluation and ReplaceRepeated

In the documentation tutorial/Evaluation it's said that: Every time the expression changes, the Wolfram Language effectively starts the evaluation sequence over ...
0
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1answer
23 views

How to keep a variable unevaluated when used as parameter for `Sum`?

Let's say I have assigned the follow value to s by s = Floor[Log[n]] Then I want to compute ...
0
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1answer
29 views

Solving a large system of equations for the smallest integer values

I'm trying to find the smallest possible non-negative integer solutions to hundreds of fairly large equations systems . An average example would be the following: ...
0
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1answer
30 views

Errors within code to change the intersection of two Log Functions

I have been asked to produce a "parametric log-log plot of s=f(y) as a function of t=g(y), where ...
2
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1answer
56 views

Function does not take many inputs, and cannot plot correctly using Listplot

I am a beginner with Mathematica. I have a function which is defined as follows: $h(x) = \begin{cases} \hfill \frac{1}{x}\sin(x) & \text{if $x\neq 0$}\\ 1 & \text{...
0
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0answers
22 views

Different results when using ReplaceAll

Here's a riddle. I have a matrix QQsimple with some algebraic expressions. For example: QQsimple[[36, 22]] evaluates to: ...
2
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0answers
36 views

What are key differences between InputNotebook and EvaluationNotebook?

I am still new to Mathematica but advancing to a point of programming notebook and cell manipulations using native commands. Sometimes they call for specifying ...
2
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0answers
80 views

Is there any way to change the box-formatting behavior thoroughly?

Background The box-formmating behavior is affected by the downvalues of the symbol MakeBoxes. But the formatting behavior is not exactly ...
2
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1answer
63 views

Trouble evaluating this definite integral, either directly or with indefinite + limits

I have the function $$ \Sigma(x) = \frac{\sqrt{R^2-x^2}(\left| R\right| -1)}{\left(R^2-1\right) \left(x^2-1\right)}+\frac{\tan ^{-1}\left(\frac{\sqrt{R^2-x^2}}{\sqrt{R^2 \left(1-x^2\right)}}\right)-\...
2
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1answer
30 views

Keep a log of evaluated expressions

Sometimes I perform some calculations, export the results and a week later I notice something odd with one of the exported files. I still keep the notebooks with the calculations but sometimes certain ...
4
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3answers
126 views

The symbolic result does not give a proper answer when inputs are specified

Define F by F[m_, k_, i_, j_] := (-1)^(m+k)/(m!*k!)*2^m*Binomial[m, i]*Binomial[k+1,j] I am trying to find this sum: ...
1
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1answer
68 views

i need to simulate a roulette table where a perosn bets $10 on red 1 time, 5 times,20 times, 100 times and 10,000 times

I need to simulate a roulette table where a perosn bets $10 on red 1 time, 5 times,20 times, 100 times and 10,000 times, i then need to find out how much the person wins or loses once they play 10,000 ...
0
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1answer
55 views

How to programmatically Evaluate Notebook (all cells in an open notebook) rather than from Evaluation menu? [duplicate]

I am working on a DockedCells toolbar for common tasks like Save, ClearAll, scrolling, etc., ...
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0answers
55 views

Running .m file from Mathematica notebook

I have use the following command to save a table called "matrix_name" as a .m file named "matrix.m": ...
1
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1answer
46 views

EntityValue evaluation behaviour

I'm puzzled by a behaviour of EntityValue, where I find it being unevaluated. Here is a minimal example. Consider the following custom ...
1
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1answer
56 views

Solve a ODE with specific conditions

I am trying to find (some) functions h(x,t) such that A h(b,t)+B h_x(b,t)=g(t), where A,B,b are constants and g(t) is a given function of time (h_x is the partial derivative w.r.t. the first component ...
0
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1answer
30 views

Why does DifferenceRoot evaluate only in this table?

I would like to use a complicated function containing DifferenceRoot as a replacement rule, but somehow it evaluates only in ...
0
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3answers
60 views

Assign value to the symbol returned by function

Ok, so here is example code: Clear[p, flag, k]; p = 2; k = 1; flag = True; If[flag, p, k] = 0; p After that I get the message ...
2
votes
1answer
39 views

How to “Hold” variables assigned value inside DSolve?

Consider the following ODE: a = 0.8; b = 8; v = DSolveValue[{ u[x] == a*(b* u'[x] + u''[x]), u[4.925] == 4, u'[4.925] == 0.625 }, u[x], x] which gives ...
3
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2answers
167 views

Why can't I evaluate this integral and obtain a closed-form solution?

I have the following spherical density distribution: $\rho(x, z) = \frac{1}{\sqrt{x^2 + z^2}\left(1+\sqrt{x^2+z^2}\right)^2}$ which I have broken into a "line of sight" dimension $z$ and a &...
0
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2answers
76 views

Still having trouble evaluating expressions (involving Log this time)

I'm trying to get some old Mathematica code working on MMA 12. I found the code at this link. Here's the relevant code: ...
1
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1answer
32 views

How does Mathematica evaluate sums where the upper limit of the index is not an integer?

I am interested in the way Mathematica evaluates sums where the upper limit of the index is not an integer - i.e., sums that are some sense mathematically meaningless. For example: ...
1
vote
1answer
103 views

Can you transcribe this mathematica expression into a formula or pseudocode?

I want to understand the mathematca formula A282720 The description says Number of nonzero terms in first n rows of the base-2 generalized Pascal triangle P_2 (But ...
0
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1answer
61 views

How to asign well numerical values efficiently before to plot?

A problem is presented when the substitution of the numerical values for this function ...
2
votes
3answers
83 views

Ignore Null when summing elements of a list, but return Null if all elements are Null

Let's say I have two different lists for which I want to compute the total list1 = {1, Null, 2, Null} list2 = {Null, Null, Null, Null} For list1, I want the total ...
0
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0answers
29 views

How to DumpSave previously assigned symbols

I'm trying to DumpSave[] some variables based on their name string. To define them, I'm using ...
2
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0answers
43 views

Which Method is used during the processing of Sum Function?

I am trying to find out which Method is used while evaluating the following function: Sum[1/((n^2)), {n, 1, Infinity}] Any help would be greatly appreciated. A ...
2
votes
0answers
114 views

How can I use Compile to Evalaute a trace of a sympolic Matrix?

I would like to evaluate a trace of a matrix of size 4Wn×4Wn at different point (x,y). with <...
5
votes
3answers
226 views

HoldForm does not prevent evaluation

I'm still relatively new here, and I'm not a native speaker. I hope, I don't make any obvious mistakes when asking this question. For instance, I simply had no idea how to title it accurately. I'm ...
1
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0answers
43 views

ArgMin returning unsolved solution

I have been trying to get the ArgMin function to work so that I can find the value of $s$ that minimizes this function: $$ f(s)=e^{-sa}\left(pe^s+(1-p)\right)^n\style{font-family:inherit;}{\text{, ...
2
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0answers
124 views

How can I numerically evaluate the trace of a large matrix to speed up the code?

I have a large matrix (4Wn*4Wn) resulted from multiplication of different matrices and I would like to evaluate the trace numerically to speed up the process. Here ...
3
votes
0answers
53 views

With notebook's default context set to “Unique to each cell group”, how do I make “Evaluate in Place” work in a text cell?

With the notebook's default context set to "Unique to each cell group", I have: x=1 The value of x = x where the second line is a text cell with an ...
0
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1answer
58 views

Compute this once, not twice

I have two questions. So, I have a function g defined in terms of another function, f: ...
1
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0answers
37 views

Why are nested anonymous pure functions shielded from evaluation?

I tried the following code (ignoring the warning messages): ...

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