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

learn more… | top users | synonyms

3
votes
1answer
35 views

How to wait a Cell in a Notebook to be executed until another Notebook's Cell expressions executed?

I have two Notebooks and I call the second Notebook from the main but main Notebook's expressions continue executing. I want them to wait until the second Notebook's expressions execution is finished! ...
1
vote
1answer
79 views

Evaluation of a Notebook

I am new to Mathematica so I do apologize if my question is too elementary. In the start of my notebook, I want to make sure that any previous definitions are wiped out so I use the ...
10
votes
2answers
371 views

Nothing not behaving as expected?

I was thinking that Nothing was doing the same job as the vanishing sequence ##&[]. Yet this exemple shows it doesn't. ...
4
votes
1answer
138 views

Where does a package have to be loaded?

I'm trying to solve a very tricky bug in my program. It's tricky because it seems to be not working intermittently, and mostly not working when running with large data sets. The code itself is kind of ...
0
votes
0answers
31 views

The problem encounterend while calling a sub notebook from the main notebook

I have two notebooks; one of them is the main notebook which will call the second notebook several times in a loop and inside this loop, matrix called as ALLB, defined in the main notebook, will get ...
3
votes
2answers
132 views

Multiplication non-deterministic?

I have two vectors of 134 elements each ($mu$, and $gt$). $mu$ contains Integers, and $gt$ contains machine precision Reals. I execute the following simple expression multiple times without changing ...
0
votes
1answer
43 views

How to use Set correctly

My codes are shown in the picture attached. I'm writing codes for numerical calculations frequently, and I think it looks neat and clear to organize input parameters in the form of table. For example,...
18
votes
2answers
307 views

Understanding evaluation and typesetting

Background So, one could be surprised by the fact that: Hold @ Grid[{{1, 2}}] (*or*) Hold @ Graphics @ Disk[] This issue and methods of prevention are ...
1
vote
1answer
83 views

How to define a function which takes another function as input in Module

Let $f$ be a function of $n$. I would like to define a function $A$ with module which takes $f[n]$ as input. So for example: ...
3
votes
1answer
99 views

Can evaluation show what was evaluated along with results? [duplicate]

After I write and evauate the following lines in Mathematica: a = 1 b = 2 x = a + b It will show only the result : 3. I want mathematica to show the following ...
0
votes
0answers
36 views

Evaluating a function after simplifying to avoid infinite expressions

My Poly[j_, s_] function simplifies to a polynomial for all j. So I defined a PolySim[j_, s_] = Simplify[Poly[j,s]] function. However, if I try to evaluate PolySim[j,0], since this is PolySim[j,0] = ...
1
vote
2answers
122 views

NIntegrate evaluates its 1st argument while it has the attribute HoldAll?

NIntegrate owns the attribute HoldAll: Attributes@NIntegrate (* {HoldAll, Protected} *) ...
9
votes
1answer
121 views

How useful is $EvaluationEnvironment?

Bug introduced in 10.0 and persisting through 10.4.1 A support case with the identification [CASE:3618534] was created. [...] I filed a report with our development team raising the issues [.....
1
vote
0answers
40 views

Using Replacement Rule on Part of List? [closed]

Why can't I use a replacement rule to replace a variable name standing in for the index of a list? For example: myList={1,2,3,4,5} myList[[index]]/.index->3 ...
5
votes
1answer
72 views

Blocking dialog with a blocking child dialog

Suppose I have a DialogInput, in which there is a Button. The Button can trigger another <...
0
votes
1answer
112 views

How to speed up my code for plotting purposes?

Below is my code in order to produce a numerical expression for the final function that needs to be plotted. I have tried to see the output of each successive expression by running the code and ...
7
votes
3answers
79 views

Kernel randomly aborting

Bug introduced in 10.0 and fixed in 10.3 So after 2 days of trying to figure out what's going on, I figure I should post here as I don't have enough knowledge about the Mathematica evaluation ...
2
votes
1answer
66 views

Generate assignment code to symbols from string

I want the function to take in string, then assign a value to its corresponding symbol. An implementation using ToExpression is ...
6
votes
1answer
57 views

Partial evaluation of symbols with non-inert OwnValues

Background: there are many, many questions here about the infamous ::setraw error. More often, than not, they have to do with repeated assignments to symbols. Here's the code: ...
10
votes
1answer
108 views

Evaluation leak from Dynamic in Button's action

a = 1; Button["Print", a++] Button["Print", Dynamic[a++]] Button["Print", Dynamic[a++];] Button["Print", {Dynamic[a++]}] Dynamic @ a The second ...
3
votes
2answers
156 views
0
votes
1answer
37 views

Replace argument of delayed function before it evaluates [duplicate]

How should I use replace so that f[x_] := x^2 Replace[f[3], 3 -> 1] OUT = 9 evaluates to 1, instead of 9? This way, the replacement of the argument is done ...
0
votes
1answer
33 views

Forcing evaluation of LinearSolve [closed]

I have a linear solve function: ls = LinearSolve[MatrixForm[Transpose[basisNScoeffs]]]; Which I then use to generate a table of solutions: ...
1
vote
0answers
35 views

Prevent infinite product from trying to evaluate?

Consider an expression involving several infinite and non-infinite products, like ...
0
votes
1answer
74 views

Mapping over function's several parameters regions [closed]

About this post: Mapping multiple parameters of a function to specific values I wonder if the parameters a and b have ranges ...
15
votes
2answers
385 views

Shell Emulation inside Mathematica

I am trying to create a Mathematica/shell syntax hybrid. I would like the following command wget -qO- "http://google.com/space line break\"" $var to be ...
3
votes
1answer
462 views

Gâteaux (directional) derivatives and higher order differentials of a functional

I would like to calculate the Gâteaux derivative of a functional (i.e. a function depending on functions). A simple example for the Dirichlet functional: $L(u(x))=\int_0^1 \frac{1}{2} (u'(x))^2 dx$ ...
2
votes
1answer
78 views

Help on order of evaluation within plot function

it is my first time asking a question here so please let me know if there's anything I should be doing that I'm unaware of. I'm sure the answer to my question already exists on the site but I'm having ...
0
votes
0answers
35 views

Creating a non-zeta-ified sum

The expression Sum[i^(-s), {i, 1, ∞}] evaluates to Zeta[s] But, of course, this is not strictly correct as ...
8
votes
2answers
69 views

How do I SetDelayed $Assumptions

For some reason, $Assumptions := (Print["y"]; x > 0) evaluates the RHS immediately. I have code in which $Assumptions ...
0
votes
0answers
42 views

Parallelization and efficiency improvement

Hey i am new to mathematica and at the moment i am writing some test code. It works but it is unrefined. I try to make it more efficient by using parallelization or other techniques. I wanted to ask ...
4
votes
1answer
495 views

Is there a method to send different Cell evaluation to different core?

I am running Mathematica on a computer with multi CPU and every CPU has multicore. I am wondering if there exist a method to send different cell evaluation to different core? So if I already have a ...
1
vote
1answer
110 views

Evaluate pure function through round brackets

In have some matrices of pure functions or numbers which I multiply by other matrices or vectors. I would like the functions to be evaluated in the result, but all that I get is something like this: <...
0
votes
0answers
21 views

How to make an expression in this case evaluated one step and stop there? [duplicate]

I wonder how to make Symbol@"m" evaluated once so that it becomes a symbol m which is ready to be assigned again. ...
2
votes
1answer
55 views

recursively structuring a multivariate numerical optimization

Suppose that I want to partition the unit interval [0..1] into four subintervals whose max length is as short as possible. I can ask Mathematica to: ...
5
votes
1answer
88 views

How can a function without an operator form be used in postfix form?

As an exercise, I was trying to convert the following Clojure code to Mathematica: ...
5
votes
1answer
47 views

How to understand the different output of two UnsetShared?

Update From technical support, Thank you for contacting Wolfram Technical Support. I understand that you are reporting an issue with UnsetShared deleting the shared variable after a second ...
2
votes
1answer
33 views

Delete Cell Inside of Module

I want to print a dynamic output while some code is running and then automatically delete it when when the output is done. PrintTemporary is not quite what I am looking for -- I want the output to be ...
2
votes
3answers
114 views

Strong glitch with Evaluate in Manipulate

I'm experiencing a strong evaluation problem for a Manipulate box and I can't find the best solution yet. Here's a MWE to show the glitch : ...
2
votes
1answer
68 views

Create a notebook and save it without prompting Dynamics

This is closely related to the recent: Creating self destructing notebook. However the answer doesn't work in my case. ...
18
votes
1answer
269 views

What is the difference between Dynamic[x] and Dynamic[ h[x] ] for DynamicModule variables?

Bug introduced in 9.0 or earlier and persisting through 10.4.1 Why plain Dynamic[x] is less sensitive and less likely to automatically be updated than e.g. ...
4
votes
1answer
49 views

Difference between Initialization Cell and Group

Is there a difference between setting a Cell or a Group of cells to be an Initialization Cell...
62
votes
4answers
6k views

Plot draws list of curves in same color when not using Evaluate

This example comes from the Mathematica documentation for Plot under Basic Examples. Can someone please explain why these are each plotted as a different color in ...
0
votes
1answer
70 views

Function Evaluation in Table [closed]

Apologies in advance: this is a really basic question, and I am sure it has been answered, but I don't know enough mathematica to even find the answer. I have a differential equation I want to solve....
1
vote
1answer
41 views
0
votes
0answers
30 views

Strange cell evaluation state

I have encountered a strange cell evaluation state (Shown in the image). It seems to be related with unknown variable a. What does this state means ? how it is different from simple error ?
6
votes
0answers
133 views

What is the difference between GenerateDocument and TemplateApply[NotebookTemplate[

Bug introduced in V10.0 and persisting through V10.4 Since V10.3 the bug still remains but additionally the Genarate and ...
2
votes
0answers
45 views

Optimization for iterating and plotting a matrix product and its elements?

I have an iterative matrix product of this type Since i didnt knew how to do it, I explicitly wrote the product as {Ayn + Bxn, Cyn + Dxn} and evaluated it with the NestList construct ...
1
vote
1answer
64 views

Calling functions defined inside Manipulate in other notebook?

I'm creating a notebook with a Manipulate and I'm trying to call/use a function from another notebook (I use Get for that), in ...
1
vote
2answers
86 views

Partial Function Evaluation [closed]

How can I evaluate only part of a stack of function calls? In particular, given f[x_,y_,z_]=x+y+z;, say, I'd like to define a function ...