# Tagged Questions

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

52 views

### An issue regarding the use of CopyToClipboard with dynamic content

Please, consider the following code: ...
363 views

### Expanding huge expressions that simplify and factor

The following is for Mathematica 8.0.4 running on Windows 7 laptop (6GB memory). I have eight expressions that are unexpanded multivariate polynomials in 6 variables. They are huge expressions, so ...
71 views

### A problem about sorting final result

Three days ago, I asked a question about B-Spline Basis fuction here @Michael E2 given a solution to make the order of interval looks normal The easiest way would be to sort it afterwards: MapAt[...
548 views

### kernel Local crashes during the course of a For loop

I want to find the minimum of the function r[x,p] subject to the constraint w[x,p,t]==0 (t ...
1k views

### Why does Mathematica evaluate Sin[2.0] but not Sin[2]?

I can't understand why is it that In[88]:= Sin[2] Out[88]= Sin[2] while In[89]:= Sin[2.0] Out[89]= 0.909297 I even tried ...
181 views

### Keep data in memory inside a notebook without having to evaluate it again [duplicate]

I have a notebook that calculates some data in a relatively large time so I want to keep these data saved inside the notebook without recalculate them every time I open the notebook. I know I can ...
105 views

### Some _atomic elements' TreeForm looks confusing with Level in appearance

In[1]:= Level[1/2,{-1}] Out[1]= {1/2} TreeForm[1/2] ...
66 views

### Simplify with assumption of unknown function [duplicate]

I have an unknown multivariate function entry[x,y,z], which is positive. Then how to get FALSE and entry[1,2,3] in the following evaluations? ...
81 views

### Mathematica automaticly evaluates some cells

Is there a command or a trick to tell Mathematica to not automaticly evaluate some cells? I use the NMinimize function to calculates some coordinates and then use ...
91 views

### Check an Option without Evaluation

Consider the following: ...
90 views

### Is there an analogue of Evaluated->False (in FindRoot) for FindMinimum?

I guess functions like FindRoot, FindMinimum, etc puts the estimation number into the expression, and then do other calculations....
54 views

### Why does FreeQ seem not to work with complex numbers?

I guess I do not understand how Mathematica evaluates this simple expression inside FreeQ ...
90 views

### Functional-Style Fixed-Length Queue Object?

Following up on question Side-effecting an array in an association? and @Mr.Wizard's answer in there, I'm modernizing and tweaking Daniel Lichtblau's efficient queues and ran into a little roadblock. ...
177 views

### Memory problem in Mathematica 10

I'm having a problem with memory. I'm doing nonliner fits of several data lists to a system of differential equations. When I evaluate the "Do" cycle the memory grows with the iteration step up to my ...
62 views

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115 views

### Assign variables from list inside With or Module

I have found that it is possible to assign variables from lists, as follows. r = {1, 2, 3}; {a, b, c} = r; b 2 However, ...
72 views

### Non-preemptive evaluation of a dynamic function? [duplicate]

I want to monitor a long calculation that is triggered by the release of a Slider. While one can indicate running calculations when the main evaluation loop is ...
407 views

### Get the approximate analytical solution to an algebra equation

Is there a way to get the analytical form to the root of this equation: 2 A e (-ArcTanh[smax/s0] + ArcTanh[(smax Cos[w ζ])/s0]) == F0 ...
146 views

### How to make Mathematica returns the exact expression I typed

I'm using Mathematica to compare some constants. Before playing around with those constants, I would like to check that I didn't make any mistake in typing them. So my question is the following: "What ...
129 views

### Evaluation inside a Manipulate

Let's assume I have a symbolic expression, and inside a Manipulate I define the actual values: ...
875 views

### Derivative of a spline approximation

To approximate an experimental data function $f(t)$ with $t \in (t_{min},t_{max})$ I used a cubic spline $s(p)=(t(p),f(p))$ with the parameter $p \in (0,1)$ and $p = t/(t_{max}-t_{min})$ by using the ...
154 views

### Time delayed evaluation of a function

I'd like to write a function that delays the evaluation of a function (say) $5$ seconds after I hit Shift+Return. Is this possible?
250 views

### Nested Derivative

These two expressions are mathematically the same, but when substituting with the same rule, yield different results. What is happening? ...
613 views

### Select sublists with second element nearest to zero

I've got some big lists from which i need some data (one of the big lists). To be specific, I need to divide this biglists in sublists of the same length (10000), and form a new list with the mean of ...
6k views

### Step-by-step definite integration

I am interested in obtaining the intermediate steps for rather straightforward symbolic definite integrations (e.g., from an elementary calculus text). As an example, for $\int_0^1 x\,dx$ I'd like ...
172 views

### Dynamic plot with Evaluate on expression

I'm trying to make a make a plot of a table of expressions, which should be pre-evaluated (since they are infinite series with analytic sums). I'm able to make the plot normally with ...
67 views

### Get the unevaluated expression from a numbered cell

If a cell exists as below: In[1] := (xyPoints = {{1,2},{2,5},{3,10}}; ListLinePlot[xyPoints]) Is it possible to get at the expression rather than the plot shown ...
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 : ...
89 views

### PasteButton: Pasting expression name without quotation marks?

I am struggling to find a way to use PasteButton to paste the name of an expression (in particular a list) without showing the contents of the expression or without ...
88 views

### Block assignments not quite sequential?

With scalars, Block acts like Scheme's let*, that is, the assignments (appear to) happen sequentially: ...
77 views

### Show [In] and [Out] tags after quitting Mathematica

I cannot find a way to show [in] and [out] tags when evaluating cells after I close the application. Is there a way to keep these shown? I disabled the kernel in global options but cannot transfer ...
74 views

### function definition with a given list of parameters: how to use Evaluate[] properly?

given a list of variables variables = {a, b, c}; I want to automatically define a function f[{a_,b_,c_},x_] := g[a,b,c,x] (...
137 views

### Handling a sequence of unevaluated arguments

I have the following piece of code: ...
280 views

### Is there a way to simplify a symbolic expression at assignment, once-for-all?

I have a series of symbolic function calls that could be greatly simplified using some assumptions. I think I would like for these assumptions to be used in the definition of the function so that they ...
129 views

### Merging two held expressions into a held compound expression

Consider e1 = Hold[a = x + x; b = y + y + y]; e2 = Hold[c = a + a + b + b + b; c^2]; How can I obtain the following? ...
125 views

### Strange results of definitions using OwnValues

I am asking this question simultatenously with this one, which is strongly related. I was trying to see if I could create the behaviour as in that question without using ...
340 views

### While loop doing cell evaluation not completing

I am trying to get a loop structure using While to repeatedly evaluate another cell referred to in its body (using a cell tag). ...
354 views

### Evaluating Polynomials at Grid Points

I am continuing my quest on B-splines. The code below builds a 5x5 matrix out of B-splines, using the BSplineBasis[] routine. I now want to evaluate the polynomials that are stored in each matrix ...
181 views

### Updating a tracked symbol inside Refresh?

I have some code inside a Manipulate, whose goal is to allow the user to edit the upper half of the matrix while keeping it symmetric at all time. The minimal code ...
2k views

### Animation of Differential Equations from NDSolve with ParametricPlot3D and Evaluate

I have a system of differential equations (referred to as "s") and use NDSolve to obtain the solution. I substitute the interpolated functions for the original ...
994 views

### A combination of Set::setraw and Set::shape errors

Please consider the following toy code: ...
84 views

### Errors in plotting regular function

Suppose we want to define Tanh-function via exponent: th[x_] := (1 - Exp[-2 x])/(1 + Exp[-2 x]); FullSimplify[th[x]] Out[13]= Tanh[x] Then we define new ...
81 views

### Singleton pattern

How can I implement the singleton pattern in Mathematica in order to ensure that a symbol is not redefined if it's already defined ? This can be useful for example with global variables in packages ...
81 views

### Evaluation speed of apparently equivalent functions

Consider the following expressions: f[x_Integer] := x, f[x_] := x /; x ∈ Integers, f[x_?IntegerQ] := x All of the expressions above (and probably others which ...
89 views

### Return the incomming expression on false

when I have an expression, that is unknown to mathematica, it is returned exactly the same, as it was called. For example SeeFlyingPigs[1,2] called on the line ...
83 views

### Need to run evaluation 2 times

Why does this only work after running the evaluation 2 times? ...
265 views

### Expectation function does evaluate my expression

I am trying to evaluate the expression Expectation[(B x (-6 b + 12 a n0 + B x + B^2 x^2))/(2 (6 a + B x + B^2 x^2)), Distributed[x, BetaDistribution[α, β]]] ...
93 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: ...
I have a complex function, lets say $g(x)$. I want to take its and its conjugate's derivative. I need the solution of derivative which must be symbolically and computationally efficient. Lets take an ...