Questions about the generation and use of compiled functions using Compile.

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10
votes
2answers
242 views

Avoiding MainEvaluate in a CompiledFunction to fetch global variables

I'm trying to write a simulation using Mathematica 8.0. Since I will most likely be doing the same operation over and over again, I'm trying to Compile whatever I ...
10
votes
1answer
200 views

Unexpected behavior of Compile, Return and ;

Could somebody explain why test = Compile[{{x}}, Return[x]; ]; test[0.] returns ...
13
votes
1answer
287 views

Using Boost with CreateLibrary

I was looking at the answer of Leonid of Faster alternatives for DayOfWeek and wanted to see how hard it would be to do something similar in C++ using an external library like Boost. I tried to ...
14
votes
1answer
519 views

Parallel compiled functions running on parallel sub-kernels

Question Why is it, that compiled, Listable, parallel functions which work perfectly fine on the main kernel, do not run in parallel on sub-kernels? Details ...
12
votes
3answers
691 views

What compilers are “suitable” for CompilationTarget->“C”?

The documentation for CompilationTarget says, "if you do not have a suitable C compiler then you will not be able to set CompilationTarget to C". Well at this time, I don't have a compiler installed ...
6
votes
1answer
184 views

DistributeDefinitions not working for compiled functions

This is fixed in Mathematica 9.0.0. I'm having trouble with parallel evaluation of compiled functions. Here is a simple example illustrating the problem: ...
12
votes
1answer
920 views

How to install and configure Intel C++ Compiler for Mathematica correctly?

I wish to try the trial version of the latest Intel C++ Compiler for Windows with Mathematica. I have downloaded the current version of IntelĀ® C++ Composer XE 2011 for Windows and installed only the ...
5
votes
2answers
154 views

MemberQ weird inside Compile

Compile[{{x, _Real, 1}}, MemberQ[x, 2]][{2}] outputs False. In fact, it seems to get compiled as ...
2
votes
1answer
212 views

how to nest parallelized computations on a cluster?

I am lucky to have access to a computational cluster and I could submit my job to many-many cores. As I need to evaluate a numerical integral within a numerical integral, I would like to know if I can ...
0
votes
2answers
763 views

nested numerical integration: not valid limits?

I encountered an error when I was hoping for some Mathematica (8.0.4) magic sparing me to code up numerical integration, function approximation and root-finding myself. The broader context and the ...
15
votes
1answer
2k views

How do I get Mathematica to recognize a C compiler on a 64-bit Windows machine?

Mathematica does not recognize any C compiler on my computer. I run Mathematica 8.0.4.0 on Windows 7. I've tried to make sure various C compilers are installed on my computer, but I'm not sure how to ...
13
votes
2answers
794 views

Speeding up random walk for many particles

I am trying to speed up this code for many particles to take a random walk. I'm not sure why it is so slow for such a simple task. I got a few hints from colleagues to reduce the precision of the ...
10
votes
1answer
302 views

Using Apply inside Compile

In this great answer a compiled version of the Nelder-Mead algorithm is presented. Since it works on arbitrary dimensions (i.e. arbitrary number of arguments), it has to use apply on the objective ...
9
votes
2answers
128 views

tol and None in output of CompilePrint

A bit of background: I'm trying to fit a very complicated symbolic function. By compiling the function I got about 100x speedup, but I would need another 10. Therefore I'm trying to understand if the ...
5
votes
4answers
660 views

Compile and “True should be a machine-size real number…” Error

I am trying to compile a little summation function. As far as I understand, because the built-in Sum function can also return ...
5
votes
2answers
662 views

Expression evaluation inside of FindRoot inside a Compiled Function

I'm trying to get some performance increase out of my own implicit differential equation solver using Compile[]. The uncompiled function is of the following form: ...
5
votes
2answers
339 views

How to set the return type of a compiled function? (Compile::noinfo warning)

I have simple function I would like to compile, but I get a warning and a call to MainEvaluate. I would like to avoid both. ...
-5
votes
3answers
1k views

Problem with Compile Function

I am attempting to Compile this function which is used to calculate a elastic collision in two dimensions. The two first coordinates of each list are the position ...
3
votes
2answers
339 views

Can SetDelayed (:=) be compiled?

Is it possible to put an If statement as below within a compile (see below)? I received a warning about SetDelayed. ...
3
votes
1answer
326 views

Explanation on why Compile statement works only if input and output sizes work

I found the following code: Compile[{{m, _Real, 2}}, Fourier[m]][Table[N[i - j], {i, 4}, {j, 4}]] which doesn't work correctly. But the following was posted as a ...
7
votes
2answers
643 views

Working with large data, pass-by-reference, compiled functions

I think I know the answer to this, but after two days of Googling, this is my last effort before going down an unwanted path... I have a function that takes lots of large data as arguments as well as ...
2
votes
1answer
3k views

Visual Studio Express 2010 on x86-64: libcmt.lib missing

The CCompilerDriver documentation explains that to use visual studio express on 64-bit targets, it's necessary to install the windows SDK after installing visual studio. I have done this, first ...
14
votes
2answers
649 views

Efficiently collecting results inside a compiled function

When we don't know the number of results that will be generated, the usual way to collect results is Reap/Sow. Another ...
83
votes
5answers
6k views

How to compile effectively?

What are the best practices of compiling functions? I understand that this is a vague question, but let me list some aspects that might trigger useful answers. Some of these have already been answered ...
17
votes
3answers
707 views

How to force Compile to return multiple results?

I would like to return two separate values from a compiled function, but Mathematica refuses to use the compiled version. Here is a narrowed-down example: ...
11
votes
3answers
745 views

Function does not compile with Greater in it

I have to speed up a matrix-calculation and would like to use Compile for it, though it fails and produces an unknown error message: ...
7
votes
3answers
474 views

Threading a compiled function over multiple arguments of different lengths

I am interested in threading a compiled function over multiple argument lists of different lengths. I will explain this in two steps: Suppose f is some function. Then one can define another ...
11
votes
1answer
333 views

Why is MainEvaluate being used when LinearSolve can be compiled?

According to this question LinearSolve can be Compiled. However, CompilePrint shows a MainEvaluate but no-warning is generated. It appears that LinearSolve is not ...
5
votes
2answers
2k views

How to use a matrix variable for a compiled function

I want to compile the following function which takes a matrix variable. ...
21
votes
3answers
588 views

Which Distributions can be Compiled using RandomVariate

Recently, Oleksandr kindly showed a list of Mathematica commands that can be compiled. RandomVariate was part of that list. However, whether this can be compiled depends upon the distribution that is ...
70
votes
6answers
6k views

List of compilable functions

Is there somewhere a list on the functions that Compile can compile, or the cases in which a particular function can be compiled that I haven't found? I'd be glad ...
41
votes
2answers
2k views

Internal`Bag inside Compile

Since Internal`Bag, Internal`StuffBag and Internal`BagPart can be compiled down, it is a ...
34
votes
4answers
3k views

How well does Mathematica code exported to C compare to code directly written for C?

Essentially what it says in the title. Mathematica can, IIRC, export it's code to C. How much overhead does that inflict on the code, as compared to writing it from scratch in C?
12
votes
2answers
182 views

How do you determine the optimal autocompilation length on your system

When you pack lists there is an overhead therefore packing a list with, say, 2 elements is likely to cost more than you get back in efficiency. Mathematica has default list lengths for which functions ...
42
votes
4answers
2k views

Speeding up this fractal-generating code

I used the code below (which is a sample from this gist containing more similar code) in my answer to my own question about Mandelbrot-like sets for functions other than the simple quadratic on ...