MATMUL_SPARSE.f90

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!    Copyright (C) 2012 The SPEED FOUNDATION
!    Author: Ilario Mazzieri
!
!    This file is part of SPEED.
!
!    SPEED is free software; you can redistribute it and/or modify it
!    under the terms of the GNU Affero General Public License as
!    published by the Free Software Foundation, either version 3 of the
!    License, or (at your option) any later version.
!
!    SPEED is distributed in the hope that it will be useful, but
!    WITHOUT ANY WARRANTY; without even the implied warranty of
!    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
!    Affero General Public License for more details.
!
!    You should have received a copy of the GNU Affero General Public License
!    along with SPEED.  If not, see <http://www.gnu.org/licenses/>.
 
 
        subroutine matmul_sparse(As, nnz, Jsp, Isp, vet_out, n, vet_in, m, error)        
 
 
        implicit none
        
        integer*4 :: nnz, i, j, n, m, error   
        integer*4 :: Jsp(nnz), Isp(0:n)  
  
        real*8 :: as(nnz), vet_in(m), vet_out(n)
 
        vet_out = 0.d0
 
              
        do i = 1, n 
           do j = isp(i-1) + 1, isp(i)
              vet_out(i) = vet_out(i) + as(j)*vet_in(jsp(j))
           enddo
        enddo
        
 
        return
        end subroutine matmul_sparse