Questions about how Mathematica evaluates expressions, tracing evaluation (Trace*), handling expressions in unevaluated form (Hold*, Unevaluated), nonstandard evaluation, etc.
2
votes
1answer
147 views
Why can't Mathematica parallelize this?
The following code makes mathematica print "ParallelTable::nopar1: [...] cannot be parallelized; proceeding with sequential evaluation."
...
2
votes
1answer
245 views
2
votes
1answer
98 views
2
votes
3answers
119 views
Function to preserve evaluation on display?
I'm looking for a function that applies the following behavior to an expression:
-When the expression is given as the full input, or as part of a function that cannot be evaluated, it remains in ...
2
votes
1answer
387 views
setting a variable equal to the output of FindRoot
So I set a function f[x]
f[x_] := x*E^(-x) - 0.16064
Then I set a variable 'actualroot' to the function FindRoot, starting at 3
...
2
votes
1answer
112 views
Implementing a For (?) or series or loop (?) for individual results for every x to n
I'm working on improving a modeling formula and have spreadsheets worth of data to use, but my work so far has been quite tedious. I'm essentially pulling 20 rows of data from each separate sheet of a ...
2
votes
0answers
42 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 ...
2
votes
0answers
88 views
Strange double evaluation using MorphologicalGraph
(MMA 9.0.0 on Mac OS/X 10.8)
Please consider the following snippet (this is as SMALL as I could make it -- my attempts at making a smaller repro-case eliminated the effect that I am investigating)
...
2
votes
1answer
224 views
GraphPlot only working when I evaluate twice
I have some code that builds a graph and some vertex coordinates, but when I evaluate it I get a message that the list of coordinates is not valid and the graph is not valid and it shows the output as ...
1
vote
2answers
82 views
What is the default file path used by the Put function and how do I pre-evaluate an expression to use in Put?
I have a problem of trying to store some output in an external file.
In one note book I define a function f[x_]:=AdvancedCalculation, where this function generates ...
1
vote
2answers
265 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 ...
1
vote
2answers
130 views
Why does Evaluate[a[[1]]]=0 assign a value to a variable while a[[1]]=0 doesn't?
I'm trying to do a small page counter with Mathematica, for leting me know about my reading progress on some books. I'm stuck on a problem:
...
1
vote
1answer
105 views
Summation of If statements
The following made me curious. Suppose you want to sum the if statement If[x[i] < 1., x[i]^2, 0.] over i=1,2, i.e.
...
1
vote
1answer
99 views
Forcing evaluation of ArgMax
How to force evaluation of ArgMax before its output gets used in Solve?
Background: I'm trying to solve for the Nash ...
1
vote
1answer
115 views
Confused about Unevaluated
Why does
Map[Unevaluated, Table[PauliMatrix[i], {i, 1, 3}]
give
{Unevaluated[{{0, 1}, {1, 0}}], Unevaluated[{{0, -I}, {I, 0}}], Unevaluated[{{1, 0}, {0, ...
1
vote
1answer
98 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?
...
1
vote
1answer
175 views
Possible to evaluate only selected cells?
Is it possible to evaluate only the selected cells programmatically that I am interested in? Say in current cell to bottom of the notebook, instead of evaluate notebook or cells?
1
vote
2answers
63 views
Prevent Mathematica to automatically evaluate Manipulate at start
I'm using an initialization cell to import a lot of data:
data = Import[myFiles];
and then I use a custom function to display this data with Manipulate:
...
1
vote
2answers
102 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 ...
1
vote
1answer
89 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 ...
1
vote
1answer
55 views
Grid — Row expressions not evaluated [closed]
Can anyone explain why in the following Grid expression the Row expressions are not evaluated ...
...
1
vote
1answer
107 views
Particular solutions of a Differential Equation not evaluated in a given case
Below first case which gives particular solutions of an OED correctly:
...
1
vote
2answers
67 views
Overloading conjugate operator for a particular function
I trying to modify the behaviour of the built-in Conjugate[] operator on a particular function I have defined, to take into account that some of its variables are real.
...
1
vote
0answers
39 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 ...
1
vote
0answers
67 views
Context “Unique to This Notebook” makes variables black even if they're not defined?
I'm trying to use this technique to keep variables separated between different notebooks. It seems to be working fine, except that variables turn black as soon as they are evaluated — any ideas why ...
1
vote
0answers
53 views
Evaluation in mapping constructs [closed]
I'm trying to use ReplacePart inside of Map, where the address of the element being replaced is the domain of the map, like this:
...
1
vote
0answers
78 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 ...
0
votes
4answers
113 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 ...
0
votes
2answers
147 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
...
0
votes
2answers
53 views
Automatically evaluating related cells
I have the cells:
In[1]:= l = 2 + 2;
In[2]:= l >= 5
After evaluating them:
Out[2]:= False
Is there a way to evaluate ...
0
votes
2answers
72 views
Symbolic evaluation fails because it exceeds $RecursionLimit
I am trying to perform a simple arithmetic in complex algebra.
...
0
votes
3answers
64 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
...
0
votes
1answer
67 views
0
votes
1answer
91 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}]
...
0
votes
1answer
81 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 ...
0
votes
1answer
91 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 ...
0
votes
1answer
84 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 ...
0
votes
1answer
62 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.
0
votes
1answer
76 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 ...
0
votes
1answer
63 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
votes
1answer
146 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 ...
0
votes
0answers
60 views
0
votes
0answers
127 views
A SetDelayed issue [closed]
I get
General::ivar: "-Cos[[Pi]/52] is not a valid variable.
when I call the function below
...
0
votes
0answers
19 views
Define a Plot3D function with custom options [duplicate]
I am trying to define a Plot3D function with custom options, following (this previous SE question), but I'm running into a brick wall. I've narrowed the problem to the following 'toy' code:
...
0
votes
0answers
29 views
Finding solutions based on set criteria [duplicate]
If anyone would be so kind, I'm wondering if I could get a basic direction in Mathematica to begin coding a method for taking a set of resources (numbers and operators) along with a set goal/answer, ...
0
votes
0answers
46 views
How to ContourPlot a Table? [duplicate]
Possible Duplicate:
Why is ContourPlot not displaying this curve?
Why do I have to put Evaluate[] here
I'm trying to plot certain contours of a function $f:\mathbb R^2\to\mathbb R$.
What I ...
0
votes
0answers
89 views
Do Import and Get work asynchronously? Can I prevent this?
I'm getting strange behavior in some of my notebooks that makes it seem like Import and Get load asynchronously. When I evaluate ...
