1
vote
1answer
48 views

Warning and Errors during Compile

I defined a compiled function cf = Compile[{{x, _Integer}, {n, _Integer}}, z = (n^x); Binomial[n, #]* StirlingS2[x, #] *(#!)/z & /@ Range[x]]; and I ...
3
votes
1answer
70 views

Usage of Block in Compile

When is there an advantage to using Block in Compile? For instance, if I have a multiple-step code, how do I decide which ...
1
vote
2answers
200 views

A fast way to compare interval

I have a list of intervall. Some of these intervals are disjoint, some are overlapped and some are included in others. To leave no ambiguity about my explanation, you can see the following examples: ...
1
vote
0answers
56 views

Linear interpolation over 2 variables

I'm tuning a function to data over 4-5 variables using Differential Evolution. The objective function calls frequently interpolation function. I came to a point, where compiling the objective function ...
5
votes
1answer
115 views

How to speed up this TDSE code?

I'm trying to build a 1D time-dependent Schrodinger equation solver, using the Crank-Nicholson method. And I think the code is kind of working now, but the speed is still slow for me. Here is the ...
10
votes
3answers
230 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: ...
4
votes
3answers
178 views

How to compile a diagonal array efficiently?

For example, if we use some functions defined prior to Compile, we usually have the main evaluators in the compiled codes, pointing to the definition of the ...
3
votes
2answers
181 views

My code for solving n queens problem Compile Failed

I want to make my code for solving n-queens problem faster, but it seems that MapIndexed can't be compiled. Mathematica return CompiledFunction::cfse: Compiled ...
4
votes
1answer
135 views

MapThread and Compile

After discovering that MapIndexed cannot be used with compile (see MapIndexed and Compile) I am now trying do implement similar functionality using a combination of ...
15
votes
1answer
228 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 ...
6
votes
0answers
94 views

Compiled function crashes kernel when trying to list over different length arguments

I'm trying to speed up a tally/binning operation that I have to run many times. I have many lists of between 1 and 10 numbers from the range [1,5] and I want to ...
14
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 ...
11
votes
3answers
507 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 ...
13
votes
3answers
374 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:- ...
7
votes
1answer
250 views

Compiling Map over expression that yields a ragged array

I'm trying to speed up a function that looks in the neighborhood of each 3D point in a large dataset and finds all the points within 1 unit in each direction, x, y, z. I've started by using ...
7
votes
1answer
479 views

Speeding up numerical Fourier Transform

I wrote this function NFourierTransform, which takes a function $f(k)$ and numerically calculates the fourier transform integral for discrete values of $k \in ...
7
votes
2answers
259 views

Compiling a spatial predator-prey model and optimising it for speed

I just made a spatial predator-prey model but it runs a little slow and I am seeking some advice on how to compile it to optimise it for speed. I first define matrix with 0 for an empty site, 1 for a ...
9
votes
1answer
592 views

Compiling a recursive formula

My question is related to computing what is called "invariant measure" for a particular well known fractal - the Sierpinski triangle. We have an array m of four two by two matrices, say ...
12
votes
1answer
285 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 ...
8
votes
1answer
241 views

Elementwise, compilable min function

I am trying to implement efficiently a transfer-matrix like algorithm. On each iteration, I have two vectors $x=\{x_1,\dots,x_n\}$, $y=\{y_1,\dots,y_n\}$ with real numbers and I need to compute the ...
7
votes
0answers
238 views

Using Compile to speed up Function with PermutationProduct

I have the following fairly simple routine dot involving PermutationProduct that I wish to speed up using ...
8
votes
1answer
328 views

Compiled version of (Norm/@coordinates)

Here I define (NormCoordinates). ...
9
votes
3answers
410 views

Compiled function error - nontensor object created

I'm trying to optimize code that uses Position MANY times. The following toy code works: ...
10
votes
3answers
636 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 ...
13
votes
2answers
768 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 ...
7
votes
2answers
629 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 ...
14
votes
2answers
633 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 ...
11
votes
3answers
724 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: ...
40
votes
2answers
2k views

Internal`Bag inside Compile

Since Internal`Bag, Internal`StuffBag and Internal`BagPart can be compiled down, it is a ...
12
votes
2answers
179 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 ...
41
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 ...