mirror of
https://github.com/triqs/dft_tools
synced 2024-12-27 06:43:40 +01:00
b534936589
- The previous version of the * operator for matrix was too clever. It was giving a lazy object and then rewriting C = A *B into gemm (a,A,B,0,C). The pb was in case of aliasing : when e.g. C = A, or is a part of A. gemm is not correct that case, and as a result generic code like a = a *b may not be correct in matrix case, which is unacceptable. - So we revert to a simple * operator for matrix that does immediate computation. Same thing for matrix* vector - we also suppress a_x_ty class. -> for M = a * b, when M is a matrix, there is no overhead due to move assignment -> however, when M is a view, there is an additionnal copy. -Correctness comes first, hence the fix. However, if one wants more speed and one can guarantee that there is no aliasing possible, then one has to write a direct gemm call. -> det_manip class was adapted, since in that case, we can show there no alias, and we want the speed gain, so the * ops where replaced by direct blas call (using the array blas interface). -> also gemm, gemv, ger were overloaded in the case the return matrix/vector (i.e. last parameter of the function) is not an lvalue, but a temporary view created on the fly.
19 lines
549 B
C++
19 lines
549 B
C++
#include "./common.hpp"
|
|
using std::cout; using std::endl;
|
|
using namespace triqs::arrays;
|
|
|
|
// to be extended to more complex case
|
|
// calling lapack on view to test cache securities....
|
|
//
|
|
int main() {
|
|
|
|
array<std::complex<double>,3> TMPALL (2,2,5); TMPALL()=-1;
|
|
matrix_view<std::complex<double> > TMP ( TMPALL (range(), range(), 2));
|
|
matrix<std::complex<double> > M1(2,2), Res(2,2);
|
|
M1()=0; M1(0,0) = 2; M1(1,1) = 3.2;
|
|
Res()=0; Res(0,0) = 8; Res(1,1) = 16.64;
|
|
TMP() =0;
|
|
TMP() = M1*( M1 + 2.0 );
|
|
assert_all_close(TMP(), Res, 1.e-10);
|
|
}
|