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

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1answer
182 views

direct assignment to the element in a Table

I have already asked a related question here why set values in this way doesn't work? But I think I have to write the question which I encountered explicitly? ...
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2answers
69 views

Evaluation of a list

I'd like to assign to $a[1],\ldots,a[m]$ ($m$ being defined beforehand) zero values. I tried Table[a[i], {i, m}] := Table[0, {m}]; but got an error message ...
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1answer
38 views

Aborting an evaluation automatically after a specified time elapsed

I use the following code to evaluate a series of notebooks: nb1 = NotebookOpen["C:\\Users\\....nb"]; SelectionMove[nb1, All, Notebook] SelectionEvaluate[nb1] ...
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1answer
63 views

How to get Mathematica to abort the current evaluation if an assertion fails?

I can turn on assertions, but they don't terminate the current evaluation. For example: ...
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1answer
131 views

GCD of Table entries

This question is from a newbie, so please be gentle in thrashing if I'm missing something very basic. How can I use GCD on a matrix/vector entries stored as Table. For example, if ...
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1answer
79 views

How to make strong assumptions?

Or put in another way, how to make a variable behave as it belongs to a specific domain, even outside the use of simplify or other commands alike? For example: ...
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1answer
134 views

How to evaluate some parts of an expression inside Hold? [duplicate]

I want to return a Hold expression but with some parts pre-evaluated. The easiest way to explain this is probably through code example. Here is what I have ...
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1answer
40 views

Evaluation order in polynomials

I'm confused by the evaluation order of polynomials containing division. Consider these two polynomials: (x^2 + y) z/w (1) a/b (2) And their tree ...
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2answers
66 views

Strange behavior of the Evaluate function

I am solving a system of differential equation whose unknown are saved under variable vec={C00,C01,C10,C11} and the solutions are saved under variable ...
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1answer
128 views

Caching data in Mathematica package

Consider the following: m=Quantity[1,"meter"] If I run the package, it will return 1m But when I load the package, the ...
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2answers
163 views

How can define a set of nested parameters

I would like to know how I to define a function with a nested set of parameters (or whatever you would like to call it). For example, how would I get the following function ...
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1answer
37 views

Please explain this pattern/Message related issue and help with finding workaround

I attempted to clean up my code and also add messages to functions if they are called with wrong arguments. This introduced some error which I tracked down to the following: ...
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1answer
37 views

Showing updating message in Dynamic with UpdateInterval

I am creating an interface which needs to repeat an operation every few seconds. The operation itself is expensive but faster than the update interval of the interface. I would like to have some ...
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2answers
61 views

Plot of function-generated lists: Why does this workaround not work?

My problem is a classic one: I want to plot a function-generated list, and there's no way to pre-evaluate (because the actual function includes NMinimize and thus ...
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1answer
47 views

How do I dynamically update “name” of Action Menu?

I have created an action menu that allows you to change the style of a cell. It works. However, I would like it to dynamically update the action menu "name". I can't get the name to refresh. ...
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1answer
39 views

How to enable automatic “grammar check” for MMA? [duplicate]

The special evaluation mechanism of MMA might make it more likely for MMA users (especially new users) to make mistakes and more difficult to find them. For example, one may have defined a function ...
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1answer
52 views

How do you programmatically update a tag using the TaggingRules mechanism?

Consider the following simple front-end code: ...
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1answer
87 views

How to Reap data from a ScheduledTask?

Here is an amusing little function mapped over a range just to iterate it. It ignores its argument and works entirely by side-effecting a global variable: ...
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1answer
67 views

RunScheduledTask and return the result

I created a task that removes itself when an external variable x,is changed: ...
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1answer
69 views

How can I force an installed, user-created palette to automatically evaluate?

I have created a palette in Mathematica v10.0.2, and used the Menu-->Palettes-->Install Palette functionality to successfully install it. When I choose my palette (from the dropdown menu), rather ...
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1answer
280 views

Trying to calculate derivatives of spherical harmonics

I am trying to confirm what is shown on this website: http://functions.wolfram.com/Polynomials/SphericalHarmonicY/20/01/01/0001/ But when I type ...
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2answers
126 views

Is this caused by round-off errors?

Let's consider this integration Integrate[ E^(4 n x s) (1 - x)^(-1 + 4 n μ) x^(-1 + 4 n ν), {x, 0, 1}] It returns ...
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1answer
60 views

Package function not evaluating

I have a short package like this: ...
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1answer
75 views

Aborting from a Dialog box

I'm trying to abort a While cycle, with a dialog box. I've tried the following: ...
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1answer
60 views

How to abort silently?

I want to Abort[] an evaluation without generating this message: $Aborted Is there a way to do this? This messages modifies my notebook, and I don't want this to ...
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1answer
44 views

Expand Expression with Nested Special Functions [closed]

I am trying to study the following sequence for $a=1$, $n \ge 1$: $$\alpha_n=(1-aq^{2n})\sum_{j=0}^{n}\frac{(aq;q)_{n+j-1}(-1)^{n-j}q^{\binom{n-j}{2}}}{(q;q)_{n-j}(q;q)_j^3}$$ using Mathematica, where ...
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1answer
62 views

Resolving Error: Mathematica evaluation order on Lists

I have a table that is 27 x 27, each entry corresponds to an element from the periodic table. I use the replacement rules in element list to allow me to convert a list of elements into a list of ...
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1answer
170 views

new kernel for notebook

I know I can create a new kernel for my notebook from the evaluation menu but is there a command for this? I'd really like some of my notebooks to startup their own kernel as the first line of code.
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1answer
78 views

Commutative algebra by generators and quadratic relations

My apologies if this has been asked before. Please also be gentle, as this is my first question here. I am trying to define a commutative algebra by generators and relations in the following way. ...
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1answer
150 views

Printing intermediate calculations in an external file, while suppressing the output in the notebook

I'm trying to construct a text-file that contains all the operations that Mathematica performs when evaluating an expression. However, i'd like to suppress all output in the notebook in which I'm ...
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1answer
43 views

Output cell written with NotebookWrite dissappears on whole notebook evaluation, yet remains if I individually evaluate it

Create a new notebook with the following two input cells: NotebookWrite[EvaluationNotebook[], Cell[BoxData[ToBoxes[Manipulator[Dynamic[x]]]], "Output"]] and ...
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1answer
128 views

About evaluation in Block

I'm completely puzzled by the following codes: Clear[func, f] a = x^2 + z; func[k_] := Block[{f}, (f[x_] := Evaluate[(a /. {z -> k})]; f[1])] func[2] ...
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1answer
482 views

How to tell Mathematica not to simplify an expression

While there is this question with a very similar title, it does not answer my question, which is: I have part of an input, in my case Re[Exp[I*x]] which ...
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1answer
200 views

Evaluate code to some point

How can I evaluate my code, up to some point? I don't want to evaluate all of my code always. I have to use Shift - Enter for every line from the first cell up to the point I want to be, and it's not ...
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1answer
281 views

Particular solutions of a Differential Equation not evaluated in a given case

Below first case which gives particular solutions of an OED correctly: ...
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0answers
56 views

Unexpected behavior of Set [on hold]

Set doesn't work in some conditions. ...
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0answers
49 views

Solving a polynomial equation with an approximate constraint is slower than the symbolic solution

Why do these two operations have such different timing, when the only difference is specifying r as approximate $0.1$ vs arbitrary-precision $1/10$? Here are the ...
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0answers
31 views

Save a Mathematica notebook evaluated [duplicate]

My notebooks can take some time to evaluate and by quitting Mathematica, I have to reevaluate every definition I've made once I restart Mathematica. Is there a way to tell Mathematica to save the ...
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1answer
48 views

Evaluation of InverseFunction at the boundaries of its domain

Folks, I want to numerically evaluate a InverseFunction h[x] close to the edges x5 and ...
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1answer
46 views

Creating a keyboard shortcut to change the Style of text [duplicate]

I'm editing a very long text in a Mathematica notebook and I'm using the "Article" stylesheet. In this text, code is highlighted using ...
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0answers
56 views

Meaning of Abs´? [closed]

A friend showed me the code below. r[i_] := {x[i, t], y[i, t], z[i, t]}; rji = r[i] - r[j]; solap = 2 a - Norm[rji]; FullSimplify[D[solap, t]] I'm unsure about ...
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1answer
59 views

Trace and SameTest in Union [closed]

This question is actually two question. First, I feel so stupid that I just don't understand the use of theSameTest option in ...
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0answers
19 views

Manipulate inside Module - “Order of evaluation conflicts” [duplicate]

In this example, Manipulate is contained within a Module: ...
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0answers
96 views

How to Implement a “Function Object” suitable for NDSolve and Finite Element Method?

I have a bunch of methods that shoud return an expression that behave like a function, i.e. an expression that, when supplied with suitable arguments, evaluate to something. A simple ...
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0answers
44 views

Unexpected order of evaluation in ForAll

I noticed that ForAll behaves rather unexpectedly when its first argument is a symbol which has been Set in an outer scope. For ...
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0answers
92 views

How can I use L.Shifrin s code formatter package better

in the document of HoldAllComplete, it says: Evaluate cannot be used to override HoldAllComplete.. for example, when I'm ...
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2answers
61 views

Coordinates of MeshPoints

The output of a set of differential equations solved with NDSolve produces a series of curves and I need to obtain the spacing between these curves at a given level ...
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0answers
87 views

Smart pointer for Mathematica?

Would the implementation of the smart pointer idea be possible in Mathematica ? Let's say I have an object "o" of the form Class[object] where object is an Association, and Class has the HoldFirst ...
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0answers
110 views

How to make a graph of this function?

I need to plot the following function: ...
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1answer
53 views

Getting Gamma as a result for integration [closed]

When finding the mean from the distribution, fx = 4*x^3*Exp[-x^4] meanx = Integrate[x*fx, {x, 0, Infinity}] I get Gamma[5/4] Could someone explain what ...