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

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1
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1answer
19 views

Chains of approximate numeric equalities

Mathematica considers two numbers equal if "at most their last seven binary digits" differ. For example: ...
3
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1answer
55 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! ...
10
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2answers
399 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. ...
0
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0answers
32 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
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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,...
1
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1answer
84 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
100 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
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2answers
123 views

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

NIntegrate owns the attribute HoldAll: Attributes@NIntegrate (* {HoldAll, Protected} *) ...
1
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0answers
41 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 ...
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 ...
3
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1answer
68 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 ...
7
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3answers
80 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 ...
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 [.....
3
votes
2answers
157 views

Is it possible to assign numbers generated in an Error-Message?

If I have a differential equation of the form ...
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 ...
10
votes
1answer
110 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 ...
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: ...
5
votes
1answer
166 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 ...
1
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0answers
35 views

Prevent infinite product from trying to evaluate?

Consider an expression involving several infinite and non-infinite products, like ...
0
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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 ...
0
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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 ...
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 ...
18
votes
2answers
310 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 ...
0
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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: ...
1
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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: <...
5
votes
1answer
89 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
48 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
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 ...
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...
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
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1answer
41 views

How do I run DialogInput and SystemDialogInput by keyboard shortcut?

I have tried modifying KeyEventTranslations.tr with code: ...
0
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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 ?
2
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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
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1answer
66 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
87 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 ...
1
vote
3answers
131 views

Multiple Plots inside a Manipulate with different dynamic variables on their x-axes

I have an expression with lots of variables, and I would like to make several plots of the expression, where the axis in each is a different variable. The idea is to put them side by side inside a <...
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 <...
1
vote
1answer
53 views

Notebook Initialization

I am running Mathematica 10.2. I am having trouble automatically initializing a notebook. I realize that there have been several other questions/answers on this topic, but the advice given there doesn'...
1
vote
1answer
66 views

How to force evaluation inside the body of a pure function?

For example, I'm writing a function to scale my list of numbers into a specific range. It goes like ...
-1
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1answer
59 views

How to plot a function, that is not properly defined in mathematica? [closed]

After rather long and relatively complicated calcuations, I finally got to a point where all my $x(t)$ functions are ...
6
votes
2answers
117 views

What is the Difference Between Rule (->) and RuleDelayed (:>)?

I am new to Mathematica so this question may seem rudimentary. Sorry for that! :) I want to implement the well-known property of Kronecker's Delta $$\Sigma_{i=1}^{n} a_i \delta_{ij}=a_j,\quad 1 \le ...
8
votes
3answers
185 views

Expand series unevaluated

I'm newbie in Mathematica. I'd like to obtain nice and verbose output for any series calculation. For example, given a simple sequence n*(-1)^(n-1) and ...
6
votes
0answers
70 views

Why Unevaluated doesn't work on unheld side of Rule/RuleDelayed?

Unevaluated is a function that I never truly understand, and here's one of the cases confusing me: ...