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

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1answer
109 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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0answers
52 views

Confusing efficiency and evaluation when returning pure functions? [duplicate]

I have a function that takes some time to evaluate, that's meant to be a polynomial approximation to a function. The polynomial is defined by a list of coefficients, so I have the function ...
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0answers
101 views

is there an equivalent of “show” steps? [duplicate]

Possible Duplicate: Get a “step by step” evaluation in Mathematica In wolfram alpha, when preforming for complicated integrals there's a 'show steps' option that explains how ...
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4answers
554 views

Specify a variable as an integer

I have a formula that always evaluates to a certain number for any variable X under one condition that X is an integer and ...
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2answers
209 views

How can I get the approximate analytical solution to this simple 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 \[Zeta]])/s0]) == F0 ...
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3answers
140 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 can only get this to work when I ...
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4answers
143 views

Minimization in single component of BSpline to extract points

I smoothed some data with a BSpline $B[t] = (x[t],y[t])$. I would like to extract certain points from this spline by their x-Values, $x_0$. The easiest way I came up with was to minimize ...
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1answer
138 views

Plot[ D[Sin[x]] ] and Evaluate[] [duplicate]

Why does t = 2 Pi; Plot[D[Sin[x],x], {x,0,t}] (* Plotting the derivative of Sin[x] *) not work, but ...
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2answers
115 views

Symbolic evaluation fails because it exceeds $RecursionLimit

I am trying to perform a simple arithmetic in complex algebra. ...
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1answer
64 views

Not evaluating all cells unless I explicitly evaluate each one?

I'm running a Mathematica (version 8) notebook. In one of the first few cells, it is supposed to plot some data. It uses a couple functions that are defined in an above cell. If I do Evaluation-> ...
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2answers
77 views
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1answer
327 views

Can graph interpolating function, but not use it. Any thoughts?

When solving a system of differential equations numerically, I get two interpolating functions. I can graph both of these, but when I try to evaluate either of the functions at a point, it just spits ...
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3answers
145 views

Evaluation in Manipulate [duplicate]

I have an expression assigned to a variable. For example: exp1 = a*x+b Now I would like to plot it using something like this ...
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1answer
110 views

NIntegrate failling on floating value

I'm trying to take the following integral NIntegrate[ ((Sin[Q 1]-Q 1*Cos[Q 1])/(Q 1)^3)^2 * S[Q,0.4,2] * Q BesselJ[0,0.5Q] , {Q,0,Infinity}] ...
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1answer
39 views

Ivar error with Fit inside Plot

I'm trying to plot this Plot[Fit[med,{1,x},x],{x,0,10}] Why this doesn't work? I find out that if I do ...
0
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1answer
107 views

Why does Evaluate fail? [closed]

If i use this code: ...
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2answers
70 views

Simplifying Fourier transform of a complicated function

I would like to evaluate the following expression but takes too much time. I would be greatly appreciate for any comments to make it fast. ...
0
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1answer
93 views

Getting unevaluated function expression

Say I've got a function f[x_] := a x^2 + b*x + c; and later set for some other reason a=1; how can I get the expression of f in ...
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1answer
89 views

Why does evaluating an integral within a Plot expression take so long? [duplicate]

I want to evaluate Plot[Integrate[Sin[((1 + 1/2) x)] (1/(2 Sin[(x/2)]) - 1/x), {x, 0, t}], {t, 0, 5}] but it takes ages to load on Corei3 computer with ...
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1answer
95 views

Evaluate integral of a series

I want to evaluate this integral, but it won't work. Does anyone knows why? ...
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1answer
246 views

NumericQ prevents evaluation at a numerical value sometimes

I set up a symbolic integral, to be evaluated only when some of the symbols have been replaced by numbers. The evaluation after assigning numbers to the symbols is still symbolic for some reason. The ...
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1answer
413 views

Array of functions, evaluation in plot

I would like to create two arrays of functions yfunc[[i]] and tfunc[[i]], with each entry of those functions being a function ...
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3answers
65 views

Automatically evaluate next cell

I am new to Mathematica. I am trying to achieve the following: I need one input cell in which I set parameters, then another input cell where functions are defined and calculations are performed. ...
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2answers
53 views

Evaluate differentiation after replacement

The problem is Find two linearly independent solutions of $2x^2y'' -xy' + (-4 x + 1)y = 0, \, x>0$ of the form $y_1 = x^{r_1}(1 + a_1 x + a_2 x^2 + a_3 x^3 + \cdots)$ and $y_2 = x^{r_2}(1 + b_1 x ...
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3answers
78 views

Preventing evaluation until all undefined symbols are resolved

FixedPoint[If[# <= 0, 0, # - 1]&, 2 x] Causes an infinite loop because of 'x'. How do i automatically prevent evaluation until ...
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1answer
85 views

Plot producing many error messages when given complicated function

I'm new to Mathematica and am running in to all sorts of silly difficulties with coding in it. I'm trying to calculate a function f[x, k], normalise it with another ...
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1answer
108 views

Can I force a function to quit and return some value after a certain amount of time has passed during its evaluation?

Imagine I provide some random input to function like FindInstance[], and I observe that, despite the existence of good solutions, the function will, with some ...
0
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1answer
182 views

Why won't ContourPlot accept a variable argument? [duplicate]

I have a list of linear inequalities which describe a (polygonal) region. I can use RegionPlot to visualize this region; but I'd also like to overlay this plot with ...
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1answer
265 views

Make Mathematica wait before replacing?

How can I force Mathematica to completely evaluate a subexpression before using a replacement rule? For example, consider the following definition (for the series of ...
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1answer
67 views

How can I restrict a notebook to evaluate only if I am user 'root'?

I am playing with openCL on Linux with an AMD gpu, and due to a glitch in the driver, I need to be 'root' to get stuff to work. Installation question here.
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1answer
130 views

Slow Dynamic Button Does Not Print [duplicate]

Possible Duplicate: Why do buttons with ChoiceDialog freeze the front end? Why is SystemDialogInput failing to return a save file path? Evaluation inside Button stops after some seconds I ...
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1answer
49 views

Simplifying a symbolic product of rational powers

I'm trying to symbolically evaluate a lot of equations that can consist of up to 10 parameters. The form of these expressions is a product/quotient of rational powers of the mentioned parameters, ...
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1answer
119 views

How does Mathematica interpret a expression?

I'm a beginner to Mathematica. I'd read several document. But I still have a problem. For example, every expression in Mathematica are of the form ...
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1answer
43 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 ...
0
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1answer
63 views

Symbolic integral including Hermite polynomial does not evaluate

I am trying to evaluate the following integral: Integrate[HermiteH[n, Sqrt[a]* x] * Exp[- (c/2)* (x^2 + y^2) + b* x * y - (a * x^2)/2], {x, - Infinity, Infinity}] ...
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2answers
78 views

Defining Piecewise Functions in Modules

In short, my question is the same as my previous one except that everything is now wrapped up in a module. The relevant code I'm working with is: ...
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1answer
99 views

Symbolic vs. numeric evaluation is incorrect [closed]

In Mathematica 9: I have two functions f[v] and g[v]. When I do f[g[0]], I get the correct ...
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2answers
229 views

Defining a function in terms of matrix elements

Currently trying to use elements from a matrix in defining a function however having some trouble. This is a somewhat simplified version of the problem. Say I have the matrix ...
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1answer
99 views

Solving NLODE with substitution

I am trying to get a solution to a non-linear ODE, below is the code that works for my problem. ...
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1answer
100 views

Order of evaluation in nested expression

I am trying to make a function that works as follows: Integrate 1 for all t in the interval $ [0,1] $ such that the first element of function vstar is positive. ...
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1answer
123 views

Understanding output of multivariable integration

I'm new to Mathematica and I'm trying to integrate this function: ...
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1answer
203 views

Pull Constants outside of integrals

I would like Mathematica to pull constants outside of an integral: e.g., $\int_0^t f[t] g[s] dt \to g[s] \int_0^t f[t] dt$ This has previously been discussed at replacement rule to pull independent ...
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0answers
12 views

Mathematica 10 Interrupt evaluation

The menu item “Interrupt Evaluation…” seems to have disappeared in Mathematica 10 on OSX. Well, this is a bummer… I personally use Mathematica for very long calculations and I was using this function ...
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0answers
74 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 ...
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0answers
39 views

Evaluation inside Compile

here's a simple question: I have a function: ...
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0answers
31 views

Expressions to functions, and evaluation [duplicate]

When calculating derivatives a expression is the result: in:= f[x_,y_]:= 1 + 2 x + 3 x^2 y + 4 x y^2 in:= D[f[x,y],x] out= 2 + 6 x y + 4 y^2 how do i make this ...
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0answers
38 views

Scoping problem with Manipulate [duplicate]

Consider the following simple code: f = Sin[a x]; Manipulate[ Plot[f, {x, 0, 10}], {a, 0, 10}] Manipulate takes f to be ...
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1answer
50 views

Optimizing repeated function calls

Easiest way to keep my library nice, is to naively call some functions many times with same parameters. Doing so prevents from zoo of (library-)global variables and complicated initialisation ...
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0answers
50 views

Numeric function not fully evaluating

I'm running into an issue where it seems Mathematica is not fully evaluating the output of my function h[t_]. I included the definition of phi[t_] just to demonstrate that it is a numerically defined ...