xref: /petsc/src/mat/ftn-kernels/sgemv.F90 (revision 58ad77e8b9ee6fdbdfef97ebcff79a2d98620aab) 
1!
2!    Fortran kernel for gemv() BLAS operation. This version supports
3!  matrix array stored in single precision but vectors in double
4!
5#include <petsc/finclude/petscsys.h>
6
7pure subroutine MSGemv(bs,ncols,A,x,y)
8  use, intrinsic :: ISO_C_binding
9  implicit none (type, external)
10  PetscInt, intent(in) :: bs,ncols
11  MatScalar, intent(in) :: A(bs,ncols)
12  PetscScalar, intent(in) :: x(ncols)
13  PetscScalar, intent(out) :: y(bs)
14
15  PetscInt :: i
16
17  y(1:bs) = 0.0
18  do i=1,ncols
19    y(1:bs) = y(1:bs) + A(1:bs,i)*x(i)
20  end do
21end subroutine MSGemv
22
23pure subroutine MSGemvp(bs,ncols,A,x,y)
24  use, intrinsic :: ISO_C_binding
25  implicit none (type, external)
26  PetscInt, intent(in) :: bs,ncols
27  MatScalar, intent(in) :: A(bs,ncols)
28  PetscScalar, intent(in) :: x(ncols)
29  PetscScalar, intent(inout) :: y(bs)
30
31  PetscInt :: i
32
33  do i=1,ncols
34    y(1:bs) = y(1:bs) + A(1:bs,i)*x(i)
35  end do
36end subroutine MSGemvp
37
38pure subroutine MSGemvm(bs,ncols,A,x,y)
39  use, intrinsic :: ISO_C_binding
40  implicit none (type, external)
41  PetscInt, intent(in) :: bs,ncols
42  MatScalar, intent(in) :: A(bs,ncols)
43  PetscScalar, intent(in) :: x(ncols)
44  PetscScalar, intent(inout) :: y(bs)
45
46  PetscInt :: i
47
48  do i=1,ncols
49    y(1:bs) = y(1:bs) - A(1:bs,i)*x(i)
50  end do
51end subroutine MSGemvm
52
53pure subroutine MSGemvt(bs,ncols,A,x,y)
54  use, intrinsic :: ISO_C_binding
55  implicit none (type, external)
56  PetscInt, intent(in) :: bs,ncols
57  MatScalar, intent(in) :: A(bs,ncols)
58  PetscScalar, intent(in) :: x(bs)
59  PetscScalar, intent(inout) :: y(ncols)
60
61  PetscInt :: i
62
63  do  i=1,ncols
64    y(i) = y(i) + sum(A(1:bs,i)*x(1:bs))
65  end do
66end subroutine MSGemvt
67
68pure subroutine MSGemm(bs,A,B,C)
69  use, intrinsic :: ISO_C_binding
70  implicit none (type, external)
71  PetscInt, intent(in) :: bs
72  MatScalar, intent(in) :: B(bs,bs),C(bs,bs)
73  MatScalar, intent(inout) :: A(bs,bs)
74
75  PetscInt :: i,j
76
77  do i=1,bs
78    do j=1,bs
79      A(i,j) = A(i,j) - sum(B(i,1:bs)*C(1:bs,j))
80    end do
81  end do
82end subroutine MSGemm
83
84pure subroutine MSGemmi(bs,A,C,B)
85  use, intrinsic :: ISO_C_binding
86  implicit none (type, external)
87  PetscInt, intent(in) :: bs
88  MatScalar, intent(in) :: B(bs,bs),C(bs,bs)
89  MatScalar, intent(out) :: A(bs,bs)
90
91  PetscInt :: i,j
92
93  do i=1,bs
94    do j=1,bs
95      A(i,j) = sum(B(i,1:bs)*C(1:bs,j))
96    end do
97  end do
98end subroutine MSGemmi
99