Questions tagged [evaluation]
Questions about how Mathematica evaluates expressions, tracing evaluation (Trace*), handling expressions in unevaluated form (Hold*, Unevaluated), nonstandard evaluation, etc.
1,444
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How to get rid of "/." in my result, when I evaluate a term containing ReplaceAll?
In the previous code I defined Bchoice and pchoice
In one line I defined
...
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0
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73
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Mathematica vs other languages such as C or Python [closed]
I need your valuable opinion on a very controversial question regarding Mathematica versus other languages, in particular C or C++. For computation, analytical or numerical in physics or other areas, ...
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2
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Understanding HoldAll?
Suppose I try to run the following code:
f[x_] := Cos[x]
F[X_] := Normal[Series[f[x], {x, X, 5}]]
Plot[Table[F[n], {n, -5, 5, 1}], {x, -Pi, Pi}]
Mathematica will ...
- 4,841
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Plot functions don't allow postfix function execution?
I'm confused about syntax of using // for postfix function execution. It fails in some situations where I would expect it to work. For example, it works with both <...
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3
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199
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How to automatically interrupt `Set` with conditions
Maybe this is a bad idea: I want to inject some conditions into Set associated to specfic symbols, like
...
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6
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1
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125
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How to stop opening of cell groups after evaluation of the whole Notebook?
Bug introduced in 12.3 or earlier and persisting through 13.1.0
I have a long notebook with Section, Subsection, ...
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1
answer
103
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Evaluation sequence visualisation + timing = nice profiling?
There is a nice way to see the evaluation sequence of a code using the function made by @WReach in this answer (copy-pasted below).
I do not understand the details of that code. Is it easy to include ...
- 532
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14
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FunctionMonotonicity[] fails, leaving the input unevaluated but shows success in EvaluationData[]
My PC is a Win 10 with MMA version 12.3.1. Today I was thinking about writing a big method/function in which FunctionMonotonicity[] would be called to determine the ...
- 403
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2
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98
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Evaluation of an iterator construct containing Sequence in Table
The following code:
Table[i*j, Apply[Sequence , {{i, 1, 3}, {j, 1, 2}}]]
returns the error:
Table::nliter: Non-list iterator Sequence@@{{i,1,3},{j,1,2}} at
...
- 2,035
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1
answer
47
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Error in evaluating a For loop
I defined an integral function and for solve it, I want to calculate it for some numbers and then plot its behavior. So I put the function in a For loop to automate this procedure and then plot the ...
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38
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Manipulate reevaluate every time
my code is working, however I have a problem, every time I navigate to the pages of the dataset, the Manipulate performs a re-evaluation bringing me back to the first page of the dataset. I would like ...
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BUG - Different Cloud vs. Desktop Return behavior in V13.1 [duplicate]
After install V13.1 one of my scripts get broke in my Mac. Here is the bug:
Module[{}, Return[1]; 2]
Return[1]
When I tested ...
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43
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A way to tell mathematica to not alphabetically order second derivatives
I have a frame of vector fields $E_1 ,... ,E_6$ and it's convenient for me to write $E_1(f)$ as Dt[f,e1] where e1 is an ...
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18
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Not getting evaluated output [duplicate]
I just started using Mathematica.
When doing the matrix calculation I encountered some problem, output is not evaluated instead it just gives the input as the output.
Example:
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Avoiding notebook re-evaluation after quitting Mathematica [duplicate]
I'm new here so I hope I'm not asking something already solved. I'm new to Mathematica and I need to manage lists created from files that usually spend a lot of time to be created. I noticed that ...
4
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4
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Parts of a Piecewise Matrix Function in NDSolve
First time posting.
Reproducing the Problem
I'm relatively new to Mathematica (using v.12.3), and working on a project. My problem can be reproduced with this.
...
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How to remember evaluation across sessions?
I am performing a very time-consuming symbolic calculation.
When I reopen a saved Mathematica notebook, it takes quite a long time to evaluate.
Is there an option to tell Mathematica to remember the ...
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answer
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Wierd problem with Table and Evaluate
I have a very unpleasent problem with Mathematica, precisely with Table and/or Evaluate. After solving a parametric system with ParametricNDSolve, I'd like to collect the values of the solutions $f_3(...
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85
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Why Mathematica don't set \$RecursionLimit and \$IterationLimit very big by default? [closed]
For my current program in Mathematica, sometimes I will encounter an error regarding \$IterationLimit and \$RecursionLimit. So I always set these two numbers to very large at the starting of every ...
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votes
3
answers
218
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Different evaluation control inside of `Integrate` than outside of it
I want to keep inside of a integral evaluated after some replacement inside it, but at the same time the integral itself unevaluated.
I start with:
...
- 2,842
6
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3
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240
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HoldForm is not working as I would expect
Why HoldForm do this?
HoldForm[a/b \[Integral]f[x] \[DifferentialD]x]
Output is this ugly looking formula:
$$\frac{a \int f(x) ...
- 2,842
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56
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Can I load a notebook without evaluating it?
I have a long notebook with a lot of definitions, calculations, etc. If I want to open the notebook on a new computer, or even on my computer after it has been shut down; then in order to make use of ...
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How to derive the integral of a first kind zero-order modified Bessel function multiplied by a Rayleigh distribution?
I input the result into Mathematica and get the following result
In: $\int_{0}^{\infty} \operatorname{BesselI}[0, \epsilon] * \frac{\epsilon}{\rho^{2}} * e^{\left(\frac{-\epsilon^{2}}{2 * \rho^{2}}\...
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Variation with respect to inverse metric in a Lagrangian density
I am trying to vary the following Lagrangian density
with respect to the inverse metric appearing in the equation, but I am having trouble with how to write the right code in Mathematica.
I have ...
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6
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4
answers
308
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How can I efficiently define functions with different names but doing the same stuff?
Recently I have met with with this interesting question:How can I efficiently define functions with different names but doing the same stuff? Somebody may want to ask me why I want to do things like ...
- 403
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votes
2
answers
148
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Double quotes as a 'function' (verbatim ToString?)
Can we construct a function F such that F makes any typed text into a string.
Just like double quotes.
...
- 3,063
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answer
49
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How to construct the local variables for Block automatically (somewhere in the code)
I am working on the fancy abstraction for Block function. The idea is to use rules to specify which local variable will be used, even if it already defined in the global context
like this
...
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3
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3
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238
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Seemingly identical expressions, only one evaluates! [closed]
I am having difficulty using NMaximize with a user-defined function that involves NSolve. Stack Trace shows trouble at the ...
- 131
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3
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111
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How to return unevaluated variable?
I'm not sure if this problem has been asked before as I don't know the keyword to search for it.
I have a function where return result contains variable b (just ...
- 2,392
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47
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Division by 0 Error when checking whether something is equal to zero
I was running a program and suddenly got Divide::infy messages coming from the following (rather ugly) expression.
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- 1,032
3
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47
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Trying to add up values into a matrix
first post here.
I'm currently completely stuck and frustrated with mathematica. In retrospective, it might had been a mistake to use it for this, I'm actually considering to somehow export the ...
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3
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270
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Expectation of a Sum
I'm using Expectation to calculate the Gaussian integral of a user-supplied function. The following works well and fast (< 1 second):
...
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Define a new rule to take precedence over the others in a symbol's `Downvalues` list [duplicate]
I have a symbol that has a very large list of Downvalues. One of the rules in this list should be applied before the others because it simplifies many expressions, ...
- 1,478
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how to split indices for a Spinor object?
I am wondering if anybody can help me with my question. My main relation is from gravity and is known as self-dual Riemann. When it is written in the Spinorial form it is like:
$$G_{\mu \nu \alpha\...
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Replace previous equations into the current one in a recurrence relation
I have a recurrence relation given as follows:
f[k + 1] == 1/a[k, k + 1] Sum[a[k, k - k1] f[k - k1], {k1,0,k-1}]
Evaluating it for ...
6
votes
1
answer
185
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Getting terms and only evaluate specific parts of a series
How to write the first five terms of this series in the following form by MMA code?
$\sum_{n=1}^{\infty} \frac{1 \cdot 3 \cdot \cdots \cdot(2 n-1)}{2 \cdot 4 \cdot \cdots \cdot 2 n}= \frac{1}{2}+\frac{...
- 1,407
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Evaluating a mathematica notebook via the command line and saving the evaluated file
I am attempting to evaluate a notebook with the following code via the command line
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43
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Multivariate function won't evaluate
When I define the following variables and function and then evaluate that function at given values:
...
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0
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41
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How to stop annoying notifications sound when using "Remove from Evaluation Queue" shortcut?
I have Mathematica 13.0 Student Edition for Windows 10 and whenever I use " Shift + Alt + / " I get this annoying "Windows" notifications sound. There has to be a way to stop it, ...
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answers
56
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Logical functions with no arguments
I am trying to understand how logical functions are evaluated if no arguments are passed to them.
{Or[], Nor[], And[], Nand[], Xor[], Xnor[]}
{False, True, True, ...
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105
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Integration of differential given as one-form
I would like to use the integration symbol in more general way, that means to integrate any differential, like
\[DifferentialD]y = a x^2 \[DifferentialD]x
and then
<...
- 577
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votes
1
answer
84
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Activating part without resolving [[1]]
I'll try to make this question more clear in a little while. In the mean time, I'll ask directly the question which motivated it:
Latin Square from submatrix
Original Question
I want, for instance, ...
- 2,762
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42
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How do I make divergent integrals to be automatically evaluated?
As a first step I want the divergent integrals to be evaluated to their Laplace transform, like this:
$\int_0^\infty \sin x dx\to 1$ because ...
- 2,911
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74
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Theoretical Timing possible? (not changes for each evaluation)
Is there a method to measure theoretic time load (hope +theoretic memory load) of an evaluation?
They should not change - always generate same value after pressing Enter key(=evaluation).
Hope they ...
- 3,063
5
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259
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Lazy vs strict evaluation approaches - performance comparison
In general, I think there are two methods of evaluating a variable in Mathematica. My question is about performance of the two methods.
Suppose that our final goal is to evaluate ...
- 3,063
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2
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172
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3
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1
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70
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Compile function dynamically
To optimize a brute force algorithm on graphs I want to compile dynamically a list of functions for a list of graphs.
(The representation I'm using for a graph is a list of pairs of integers: integers ...
- 471
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68
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Why does Plot function have HoldAll attribute?
I had an odd issue where my plot wasn't drawn correctly when I called it via Plot[Join[fs,gs], (*..*)]. However, these two versions worked:
...
- 111
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141
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Help with Error: Recursion depth of 1024 exceeded during evaluation
I am quite new to Mathematica. Please excuse my mistakes. I would appreciate if you could help me with the following set of commands.
...
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1
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72
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How to count Kernel evaluations then call a function on every nth evaluation
On every nth (2) evaluation autoEval should invoke a function check[]. The thing which is supposed to listen for all ...
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