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

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5
votes
1answer
49 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
34 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
71 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
276 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
52 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...
63
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
71 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
42 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
134 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
46 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
71 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
89 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
145 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 <...
1
vote
1answer
56 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'...
10
votes
2answers
270 views

The introduction for Context in Wagner's book is out of date? [duplicate]

In Section 8.1.1 (P230 of the book, P249 of the PDF) of Wagner's book, the following example is shown: x = 5; temp`x = 6; Begin["temp`"]; {x, Global`x} The ...
1
vote
1answer
68 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
votes
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 ...
12
votes
7answers
629 views

How to properly inject iterators into table? [duplicate]

Goofing off on a prior question, I was fiddling with other methods, which led me to the need to inject a constructed set of iterators into a table construct. Now, ...
8
votes
3answers
188 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
71 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: ...
8
votes
1answer
148 views

Why one needs two Unevaluated to show 1+1 correctly in TreeForm?

The task sounds simple, give the tree plot of 1+1. However, after some trying, I can only make this possible by using two Unevaluated. ...
1
vote
1answer
60 views

Convert an evaluated in place code to original

I like "Evaluate In Place," because it hides code and works well. However, I can't figure out how to return to the original code when I want to modify it. I'm sure there is an easy way, but I can't ...
13
votes
3answers
468 views

Handling Kernel quit

One can use $Epilog to do something when the Kernel is quit or put an end.m file next to the ...
0
votes
0answers
45 views

EvaluationMonitor and variables with indices + subscripts

I have encountered the following problem while using EvaluationMonitor with NMinimize: variables that have both a subscript and an index, e.g. Subscript[x,y][1] do ...
0
votes
3answers
209 views

Avoid creation of OwnValues when inserting transformation rules into Experimental`OptimizeExpression

I have a large list of transformation rules that I want to simplify. I find Experimental`OptimizeExpression works as it gets me the answers. My question is: I ...
9
votes
0answers
69 views

Is there a way to TagSet a HoldAllComplete function?

Let's say I want to overload the built-in function Lookup, to handle my data wrapped in myObject. One would use ...
8
votes
1answer
926 views

Creating self destructing notebook

Inspired by this post I've been trying to implement the idea in Wolfram with no success yet. I've come pretty close though and need some help. So I've managed to do this: ...
1
vote
0answers
111 views
22
votes
3answers
433 views

Can't inject EncryptedObject

Bug present from 10.0 to 10.3.1 and fixed in 10.4.0 !! Here are minimal examples: ...
8
votes
1answer
221 views

Trouble with polynomial multiplication

Bug introduced in 10.1.0 and fixed in 10.4.0 ...
0
votes
1answer
42 views

Computing approximations of exponential [closed]

I have the code f[x_] := 13 x e^-x bit = Nest[f, 1, #] & /@ Prepend[1]@Range[4, 16, 4] Which I am using to compute values of $f^{(4)}(1), f^{(8)} (1), \...
3
votes
1answer
97 views

Map works but Thread doesn't

This question may be trivial, but I can't get past it for the life of me. I have $n$ matrices of dimension $p_i \times N_i$, with $i$ indexing the $n$-set. I also have $n$ vectors of the appropriate ...
7
votes
2answers
187 views

How to track Part of Symbol or How to symbolize Parts of Symbol without copying data

Let's create simple function: SetAttributes[h, HoldFirst]; h[data_] := Dynamic[Grid[data], TrackedSymbols :> {data}] test = RandomReal[1, {2, 2}]; h[test] ...
13
votes
2answers
382 views

ScheduledTask with scoped variables. Working with timed evaluation

I guess I have to try harder and focus more but timed evaluation always frustrates me. I will show the issue on simple example of delayed trigger. ...
3
votes
1answer
52 views
5
votes
2answers
152 views

Evaluate numerically an extremely small number

How to evaluate numerically $e^{-4 \cdotp 10^{35}}$ in the form $0,a_1a_2...\times 10^{-n}$ ...
4
votes
1answer
73 views

Strange behavior of ArcTan [duplicate]

I've noticed a strange behavior of Mathematica's ArcTan function with two arguments. If both arguments are 0 or ...
2
votes
1answer
50 views

Recognition Power Head for numeric value

We know: Map[Head, {a, a^2, a^3}] (* {Symbol, Power, Power} *) and Map[Head, {2, 2^2, 2^3}] all of them will be known as <...
1
vote
0answers
43 views

How can I use x->Root outputs from Solve? [duplicate]

Do not understand the meaning of the output given by Mathematica to this equation: ...
0
votes
1answer
51 views

Manipulate curves [duplicate]

I want to draw curves with manipulation. When I use the following code, I receive nothing. ...
6
votes
0answers
49 views

How trap expression that doesn't evaluate?

If evaluating an expression produces an error, it's easy to trap that using Check or Throw......
1
vote
1answer
37 views

Access variable middle of the run [duplicate]

I execute a Table[] that need large time to be finished. If I abort it I loose what evaluated until now. Does it possible to stop running and save what evaluated ...
12
votes
1answer
892 views

Why is this 2D plot so slow?

I first do a 3D Plot of four surfaces (eigenvalues of a $4\times4$ matrix) over $kx,kz$ (setting $ky=0$ all along). And then I try to give a 2D plot along three connected particular lines in $kx,kz$-...
11
votes
4answers
199 views

Evaluation of Alternatives

I recently stumbled upon a few examples that suggest patterns containing Alternatives do not evaluate for individual alternatives. For example: ...
1
vote
0answers
82 views
7
votes
1answer
320 views

How is LHS = RHS; … ; LHS (nontrivially) different from … ; RHS

I'm trying to understand how Mathematica thinks about the results of Set. Suppose we perform LHS = RHS. I'm focusing on when ...
0
votes
0answers
42 views

Substitute arguments before evaluating variables in Block [duplicate]

Suppose I have f = x^2; mod[x_] := Module[{}, f] Then mod[3] returns x^2. Is there any way to tell Mathematica to treat the "x" inside of f as the same "x" as ...