mirror of https://gitlab.com/QEF/q-e.git
31 lines
835 B
Fortran
31 lines
835 B
Fortran
!-----------------------------------------------------------------------
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subroutine pw_dot(sum_over_nodes,n,m,a,lda,b,ldb,c)
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!-----------------------------------------------------------------------
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!
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! calculate m dot products c_i = real( a^*_ij b_ji )
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! using half G vectors or half PWs
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!
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#include "machine.h"
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use parameters, only: DP
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use pwcom, only: gstart
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implicit none
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! input
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integer :: n, m, lda, ldb
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character(len=1) sum_over_nodes
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complex(kind=DP) :: a(lda,m), b(ldb,m)
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! output
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real(kind=DP) :: c(m)
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! local
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integer i
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real(kind=DP) :: DDOT
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!
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do i= 1,m
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c(i) = 2.d0*DDOT(2*n,a(1,i),1,b(1,i),1)
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if (gstart==2) c(i) = c(i) - real(a(1,i))*real(b(1,i))
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end do
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#ifdef PARA
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if (sum_over_nodes.eq.'y'.or.sum_over_nodes.eq.'Y') call reduce(m,c)
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#endif
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return
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end subroutine pw_dot
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