njpipeorgan / wll-interface Goto Github PK

First of all, thanks for sharing this amazing project! This project is not only very useful in practice to ease the interaction of C++ in Mathematica, it also demonstrates greate C++ programming skills of implementing the whole system compactly.

When running in ubuntu 18.04, the sum of an array example doesn't seem to work for me. It crashes the Mathematica kernel.

This is the process I used to build and load the library in Mathematica:

<<CCompilerDriver`
CCompilerDriver`$CCompiler={
"Compiler"->CCompilerDriver`GenericCCompiler`GenericCCompiler,
"CompilerInstallation"->"/usr/bin","CompilerName"->"g++-7"};

src="
#include <numeric>
#include \"wll_interface.h\"
double sum(const wll::list<double>& a)
{
    return std::accumulate(a.begin(), a.end(), 0.0);
}
DEFINE_WLL_FUNCTION(sum)";

mylib=CreateLibrary[src,"wll_sum",
"IncludeDirectories"->{"/root/wll-interface/include"},
"CompileOptions"->"-std=c++17 -fPIC"]

mylib=CreateLibrary[src,"wll_sum",
"IncludeDirectories"->{"/root/wll-interface/include"},
"CompileOptions"->"-std=c++17 -fPIC"]
sum = LibraryFunctionLoad[mylib, "wll_sum", {{Real, 1, "Constant"}}, Real];
sum[{1,2,3}]

I'm using gcc 7.4 on ubuntu 18.04: g++-7 (Ubuntu 7.4.0-1ubuntu1~18.04.1) 7.4.0

Do you have any ideas or suggestions for the potential cause?
Thanks.

It seems that calling an external library in a library function leads to crash of mathematica kernals.

These are the steps to reproduce the crash:

File /tmp/external_lib/addone.c:

int addone(int x){
    return x+1;
}

Compile to dynamic library

gcc -Wall -fpic -shared -o libaddone.so addone.c

which generate file /tmp/external_lib/libaddone.so

Load into Mathematica

src = "
  #include <wll_interface.h>
  int addone(int x);
  int test(int x)
  {
  	return addone(x);
  }
  DEFINE_WLL_FUNCTION(test)";

CCompilerDriver`$CCompiler = {"Compiler" -> 
   CCompilerDriver`GenericCCompiler`GenericCCompiler, 
  "CompilerInstallation" -> "/usr/bin", "CompilerName" -> "g++-7"}

mylib = CreateLibrary[src, "wll_test", 
  "IncludeDirectories" -> {"/home/mengxiwu/.Mathematica/include"}, 
  "LibraryDirectories" -> {"/tmp/external_lib/"}, 
  "CompileOptions" -> "-std=c++17 -fPIC", 
  "LinkerOptions" -> "-laddone"]

test = LibraryFunctionLoad[mylib, "wll_test", {Integer}, Integer]
test[3]

Any ideas for the crash? Thanks.

Thank you for developing wll-interface, it's been incredibly useful in my personal projects. My question is:

Is there a way to return a wll::tensor by-reference if the dimensions are not known a priori?

Right now, I'm splitting up any C++ routines that have multiple returns into:

• one function that calculates the outputs and writes them to some global variable
• "getters" that access that global and return each output individually

Returning multiple things by-reference would be cleaner and thread-safe, but when I tried it, my C++ functions that resized the by-reference output wll::tensors caused the kernel to crash.