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

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105
votes
5answers
9k 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 ...
98
votes
8answers
8k 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 ...
48
votes
2answers
2k views

Internal`Bag inside Compile

Since Internal`Bag, Internal`StuffBag and Internal`BagPart can be compiled down, it is a ...
44
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 ...
38
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 export its code to C. How much overhead does that inflict on the code, as compared to writing it from scratch in C?
33
votes
4answers
1k views

Compiling more functions that don't call MainEvaluate

I would like to use Compile with functions defined outside Compile. For example if I have the two basic functions ...
24
votes
3answers
848 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 ...
21
votes
3answers
970 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: ...
21
votes
1answer
306 views

Performance regression for Fold?

Bug introduced in 8.0 and persisting through 10.1.0 or later I noticed an over 10x performance drop on Mathematica v9.0.1 (as Oleksandr R. commented, also v8) compared with v7.01 for this code: ...
18
votes
1answer
277 views

Performance of compiled functions

I am trying to find the fastest way to calculate two values where both of them are sum of different expressions. I combine both calculations in one Sum[]. I'm ...
18
votes
1answer
3k 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 ...
17
votes
1answer
689 views

Has this implementation of FDM touched the speed limit of Mathematica?

Still, I'll use the implementation of the 1D FDTD method (you can simply understand it as a kind of explicit finite difference scheme for the Maxwell's equation) as the example. Just for completeness, ...
16
votes
2answers
1k views

Fastest way to measure Hamming distance of integers

I am looking for a fast and robust way to calculate the Hamming distance of integers. The Hamming distance of two integers is the number of matching bits in their binary representations. I expect that ...
16
votes
2answers
783 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 ...
16
votes
2answers
257 views

Third argument of Compile

In his last comment on this answer, halirutan shows an example in which the third argument of Compile does not have any effect. The example is as follows. ...
16
votes
1answer
662 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 ...
16
votes
1answer
756 views

What technical obstacles prevent all Mathematica code compiling to C

The following represents an attempt at a very simple view of the levels in Mathematica code: We have had lots of questions about deployment and compiling Mathematica code to C. Some of these for ...
15
votes
0answers
221 views

Compile not correctly initializing a variable defined inside Module

Bug introduced in 8.0 and persisting through 10.1.0 or later In the following example, inside the minimumX's Module, ...
14
votes
4answers
636 views

Can (compiled) matrix permanent evaluation be further sped-up?

Update II  Sample code for simulating boson-sampling experiments has been added (as an answer). This code exploits new Mathematica capabilities relating to both empirical and smooth ...
14
votes
3answers
449 views

Quick multiple selections from a list

What is the fastest way to make multiple selections from a list? Compiled methods included. For example, here are two methods for selecting a subset, compared:- ...
14
votes
2answers
866 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 ...
14
votes
2answers
177 views

CompiledFunction returns machine numbers smaller than $MinMachineNumber

When thinking on the workaround for this LogLogPlot bug suggested by halirutan I noticed that CompiledFunction actually can ...
14
votes
1answer
220 views

Is the CompiledFunctionCall WVM opcode efficient?

There is example in Mathematica documentation about Compile ...
14
votes
1answer
367 views

Is the sharing of variables in Module/Block within Compile documented behavior?

Today I noticed something, I think for the first time. When used inside Compile variable values within Module (and ...
14
votes
1answer
1k 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 ...
14
votes
1answer
289 views

How can you profile compiled code?

Is it possible to profile compiled code? I am using Workbench 2.0 and the Profile[] command but I do not get a profile of my compiled function. I apologize if the answer is readily available but I ...
14
votes
1answer
312 views

In Compile “InlineExternalDefinitions” doesn't work anymore in Mma v10 like in v9

In Mma 9 using CompilationOptions -> {"InlineExternalDefinitions" -> True} inside of Compile inlined the values of the ...
13
votes
1answer
415 views

Why is MainEvaluate being used when LinearSolve can be compiled?

According to this question LinearSolve can be compiled. However, CompilePrint[] shows a call to ...
13
votes
1answer
364 views

Removing calls to MainEvalute when using inlined compiled closures

This question is tightly related to the answer Shaving the last 50 ms off NMinimize. There @OleksandR shows how inlined closures can be used to eliminate calls to ...
13
votes
1answer
325 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 ...
12
votes
3answers
900 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: ...
12
votes
2answers
582 views

How can I compile this function

I want to simplify my function f1 to f2, but f2 can't be compiled. How can I make it ...
12
votes
3answers
887 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 ...
12
votes
1answer
447 views

Save a C compiled function without losing the blessing of C compiler

Consider the following example: ...
12
votes
1answer
164 views

CompiledFunctionCall vs. LibraryFunction

When compiling code to C, and the compiled code calls other compiled functions, I see CompiledFunctionCall in the output of ...
12
votes
1answer
471 views

What function generates random numbers in a compiled function?

I am writing a simulation for 2D random walk. I wrote several version of code, and found that the speed is like this (fastest to slowest): C++, Mathematica compiled procedural code, Mathematica ...
12
votes
2answers
197 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 ...
12
votes
2answers
657 views

Using Goto and Label in compiled function?

Below I post some rudimentary code to show that there is something wrong using Goto and Label commands in compiled functions (or I believe there is something wrong). It seems that the command Label is ...
12
votes
1answer
242 views

MapIndexed and Compile

I am having trouble compiling a function that uses the MapIndexed function on the second level. The compilation runs fine, but at evaluation time I get an error ...
11
votes
2answers
267 views

Can RecurrenceTable make use of CompiledFunction?

I'm trying to implement a discrete-time 2D Verlet algorithm for a point-mass subject to a softened gravitational interaction as a test for a more computationally intensive simulation using ...
11
votes
3answers
695 views

Efficient implementation of a linear complexity measure of binary sequences

For a implementation of testing the quality of random number generators I implemented the NIST test suite in Mathematica based on the nice workbook by Ilja Gerhardt. However I took up the challenge ...
11
votes
1answer
703 views

Example program for calling Mathematica from C

I want to call Mathematica from a C program. Suppose I have two numbers x = 2 and y = 3. I want to define ...
11
votes
1answer
270 views

Bizarre behavior of With, Compile and Break

I'm guessing this is almost certainly a bug in Compile (because they're fairly common), but it's pretty weird and I spent about an hour tracking down the issue and ...
11
votes
1answer
337 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 ...
11
votes
1answer
302 views

Is it possible to use Compile on a function with optional arguments?

My Mathematica is a little rusty, so apologies in advance. I think my problem is quite simple, but I can't seem to find the answer on my own! Simple example : ...
10
votes
2answers
273 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
2answers
409 views

Compiling LinearSolve[] or creating a compilable procedural version of it

Earlier today I had a discussion with a representative at Premier Support about the 2 questions I've asked here over the past couple of days: Seeking strategies to deploy a function securely ...
10
votes
1answer
971 views

Using a compiled function inside NIntegrate gives “CompiledFunction::cfsa” message

The following function is defined for Real input: FFc = Compile[{{x, _Real}, {EF, _Real}},If[x > EF, 0., If[x == EF, 0.5, 1.]]] FFc is now used in the ...
10
votes
3answers
250 views

Can I return lists with different dimensions from a compiled function?

Sometimes I'll need several lists with different dimensions to be returned by a compiled function, but compiled function will fail if an irregular list contained: ...
10
votes
1answer
271 views

Unexpected behavior of Compile, Return and ;

Could somebody explain why test = Compile[{{x}}, Return[x]; ]; test[0.] returns ...