# Tagged Questions

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

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### Why does this simple sum function fail to compile?

Consider the following compiled function, which takes a $12 \times 5$ array $x_{ij}$ of real numbers and computes the triple sum $$\sum_{k=1}^5 \sum_{i=1}^{12} \sum_{j=i+1}^{12} x_{ik} x_{jk}.$$ <...
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### Closing over array values makes Compile choke with CompilationTarget -> “C”

When I attempt to Compile a closure which contains an array of the appropriate type, it works just fine with ...
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### Numeric error in trivial compilation

I came across this strange problem: dd = Compile[{}, Abs[(10^-200 + 10^-200 I)/(10^-200 + I 10^-200)]^2, CompilationTarget -> "C"] dd[] ...
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### Module inside module in Compile

How can I make compilation to go through with a module inside module? I tried this, failed, a few other ways failed too. ...
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### Is tensor argument passing to module expensive?

I wrote a simple module which is supposed to do recursive computation, however it turns out to be expensive even for 300 points. I am not sure why is it slow, all the computations seem to be ...
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### Memory usage of compiled function: C vs WVM

Reported to WRI [CASE:3406803] Why does generating an array in "C"-compiled function uses 50% more memory than doing same thing in ...
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### How to solve coupled complex-valued equations faster and get simplified solution

I have six coupled equations. How to solve these equations symbolically faster in Mathematica. In these equations, variables p,q,x,y are ...
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### Compile a listable function to be applied over list of lists [closed]

Consider a simple function g[x_,y_,z_] := x + y + z; (indeed, any multivariate function g will illustrate the same thing). ...
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### Use Compile to improve performance

I've recently discovered Compile as a way to optimize my code. I wrote a program to learn something new about Compile. I have a ...
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### How to use Compile to generate an $n×n$ array using $n$ tensors with both Real and Integer element

This is an extension of my earlier questions Faster use of Condition for a large array (see the example) and How to use Compile to generate an $n\times n$ array using $n$ vectors . In this case each ...
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### Listable compiled function crashes the kernel with “no more memory available”

Bug introduced in 9.0.0 and fixed in 10.3 I am trying to speed up a function that involves continued fractions. Since ContinuedFraction cannot be compiled and ...
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### Undeclared Identifier error in Compile

I've been trying to compile a couple of functions in Mathematica, and I keep coming across an error that I do not know how to resolve. Consider the following function: ...
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### Using Compiled Function in Implicit Region

I am looking for a way to speed up code and thus would like to use a compiled function in an ImplicitRegion. Here is an example of a region that can be plotted ...
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### CompilationTarget to C takes long compilation time

Consider I have a function, with one version that compiled to the virtual machine and one that compiled to C: ...
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### How to compile procedural program effectively

Consider these four function in different form: ...
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### How to use Compile to generate an $n\times n$ array using $n$ vectors

Let's consider the following: ...
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### How to speed up an optimization with very long symbolic expressions?

I have 8 very long symbolic expressions (each having around 200,000 summands) - Simplify will run forever, so that is unfortunately not an option. Each of those ...
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### Use a part specification as the argument to a compiled function

I have some code that needs to generate a large matrix based on some complicated combinations of smaller matrix elements. I find that if I write a function for the element of the larger matrix, and ...
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### CCompile Problems

Operating System: Windows 8.1 Mathematica: 8 In possession of: Visual Studio 2013 and 2015 Had to alter the visual studios driver file within CCompilerDriver application, add-on so that it found the ...
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### 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 ...
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### How to use Wolfram language in an external program with low latency? [duplicate]

Im using Wolfram language on Pi B,and I want to compile a '.m' file (like "test.m" that contains Wolfram functions), in an external program like a C/C++ and then Export the output in an image file ...
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### Compiling FoldList implementation for RK4

Original I'm looking to write an integrator for a function of two variables. Here is my implementation for the RK4 update rule using FoldList. ...
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### speed up evaluating a listable function [duplicate]

I apologize in advance for the vagueness, but I can't think of a more descriptive title. I am trying to find the average value of the square of BesselJ[0, x] ...
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### What is a good way to code long, complex, compilable algorithms?

The functional paradigm of the Wolfram Language used in Mathematica is all around wonderful. For intense numerics, Mathematica comes with the ability to Compile ...
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### How to build recursive function which only remembers every pth value and the last two values?

I need to create a recursive function of the natural numbers $f$ which only remembers the last two values it has found and every $p$th value. Below is the form of the code that I am working with, but ...
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### How to compile this function

I want to compile my function that calculates the energy of a particle system. This is what I've tried: ...
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### Problem with Compile and Flatten

I want to get two lists within a compiled function, where r is an integer: ...
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### Improve simulation speed using Compile

I have two square matrices, a hermitian matrix h and an unitary matrix v. I am interested in the following function ...
323 views

### Compiling a function that takes lots of optional arguments

I have a function that takes lots of optional arguments (basically some design parameters, about 10 of them) and performs some basic algebraic calculations involving complex numbers with the options. ...
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### CompiledFunctionCall vs. LibraryFunction

When compiling code to C, and the compiled code calls other compiled functions, I see CompiledFunctionCall in the output of ...
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### Save a C compiled function without losing the blessing of C compiler

Consider the following example: ...
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### NIntegrate-ing a compiled function

I'm trying to integrate numerically in 6 dimensions a very long expression and I read about the option to NIntegrate a compiled function which should be faster. ...
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### A problem with Compile and Map

There is a weird behavior of Compile that I do not understand. Consider the following example: ...
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### Error from Compile with a sum over two indices

I have the following code: ...
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### What is the meaning of the lists of numbers in the FullForm of a compiled function?

For example, f = Compile[{{x, _Real}}, x]; FullForm[f] has this output: ...
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### Why does Compile redo the calculation when overflow happens?

When implementing the Numerov method solving Schrodinger equation, I encountered this problem. In order to show the order of the evaluation, Print is added. ...
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### Numerical 3D Integration in Mathematica [closed]

My question in short is: Is it possible to make numerical 3D integration in mathematica efficiently? Or am I gonna have to move this to C++? I feel this problem is way too trivial to go to C++, so ...
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### Step-by-step instruction to Install C Compiler

I remember using C compiler on my previous computers, and I never had any problems installing them. At this time, however, I failed to work through the instructions provided in Mathematica ...
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### Compilation of Total with compensated summation

I sometimes obtain an unexpected error when trying to call a compiled version of Total with compensated summation turned on. More specifically I define ...
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### How to get Mathematica to compile with target C? [closed]

I have been trying to compile some functions in mathematica with target C for speed. basically when I try: ...
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### Compile, “global variables” and recursion

I am trying to do something similar to this, namely to make a Compile'd function outer that itself calls a ...
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### Dynamic arrays and lists with compile (Append, Linked lists etc.)

I have a code that I need to compile. The code contains a loop in which I need to gather data into a list. The question is how to best gather data so that the code works inside Compile. The following ...
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### Correct use of Solve inside Compile

I have a function that behaves itself, but I want to make it much faster so I tried to put it into a compilable form After much fiddling I can't get it to work. Here's one of my failed attempts: <...
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### Why do messages only appear first time I evaluate my compiled function?

I declare my compiled function: ...
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### Slow-down encountered when using NMinimize with a compiled function

I'm minimizing a large function. Evaluating the function is very slow symbolically but using Compile I can get ~100x speed-up on this step. However, despite this, the NMinimize process is only ...
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### Goto and Compile to C

When I use Goto inside compile and use CompilationTarget->"C" I get error message: ...
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### Throw and Catch return wrong result inside Compile

Consider this code: fun = Compile[{{i, _Integer}}, Catch[Do[ If[j >= i, Throw[j]] , {j, 1, 10}]] ] I put an integer as argument then if this ...
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### Throw and Catch or Return inside Compile

Consider this code: ...