The `\` operator is broken for dense matrices

[fredrikbk]

[fredrikbk]

LU should also be exposed as a set of intrinsics:

• lu(A : matrix) -> solver : opaque
• lusolve(solver : opaque, b : vector) -> x :vector
• lumatsolve(solver : opaque, B : matrix) -> x :vector
• lufree(solver : opaqie)

[VikingScientist]

The backslash solver crashes for even minimal exampels. By using the following C-code

#include "program.h"                                                           

int main(int argc, char **argv) {                                              
    simit::init("cpu", sizeof(double));                                        

    simit::Program program;                                                    
    program.loadFile(argv[1]);                                                 
    simit::Function func = program.compile("main");                            

    func.runSafe();                                                            
}

and the following sim-program

func main()
    var A : matrix[3,3](float) = [1.0, 0.0, 0.0;
                                  0.0, 1.0, 0.0;
                                  0.0, 0.0, 1.0];
    var b : vector[3](float)   = [1.0, 2.0, 3.0]';
    var c : vector[3](float)   ; 
    c = A \ b;
end

I get segmentation fault at .../simit/src/runtime.h:24

[fredrikbk]

Yes, it only works for sparse (system) matrices at the moment. That's definitely a bug.

[fredrikbk]

The \ operator now calls LU. Still need to add support for the LU builtin's and fix the bugs @VikingScientist reported.

[fredrikbk]

Added the intrinsic. Now it's just the bug left.