root / synthbench / euroben-dm / mod2b / .svn / text-base / getrs.f.svn-base @ 0:839f52ef7657
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Subroutine getrs( m, n, a, lda, ipiv, b, info ) |
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! ----------------------------------------------------------------------- |
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Use numerics |
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Use dist_module |
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Implicit None |
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Include 'mpif.h' |
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|
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Integer :: m, n, lda ! Dimension of factorization |
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Integer :: info ! Result parameter (always zero) |
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Integer :: ipiv(*) ! Pivot indices |
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Real(l_) :: a(lda,*) ! Factorization |
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Real(l_) :: b(*) ! Input vector, overwritten by solution |
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Logical :: send |
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Integer :: i, j, k ! Counters |
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Integer :: comm, ierr |
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! ----------------------------------------------------------------------- |
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info = 0 |
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comm = MPI_Comm_World |
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|
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Call laswp( 1, b, m, 1, m, ipiv, 1 ) |
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|
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Do i = 1, m ! --- Solve L*Y = X |
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If ( me == owner(i) ) Then |
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If ( b(i) /= 0.0_l_ ) Then |
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j = localindex(i) |
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Do k = i+1, m |
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b(k) = b(k) - a(k,j)*b(i) |
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End Do |
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End If |
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End If |
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If ( i /= m ) Then |
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Send = ( owner(i+1) /= owner(i) ) |
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Else |
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Send = .TRUE. |
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End If |
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If ( Send ) |
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& Call MPI_Bcast( b, m, MPI_Real8, owner(i), comm, ierr ) |
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End Do |
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|
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Do i = m, 1, -1 ! --- Solve U*Z = Y |
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If ( me == owner(i) ) Then |
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If ( b(i) /= 0.0_l_ ) Then |
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j = localindex(i) |
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b(i) = b(i)/a(i,j) |
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Do k = 1, i-1 |
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b(k) = b(k) - a(k,j)*b(i) |
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End Do |
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End If |
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End If |
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If ( i /= 1 ) Then |
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Send = ( owner(i-1) /= owner(i) ) |
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Else |
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Send = .TRUE. |
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End If |
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If (Send) |
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& Call MPI_BCast( b, m, MPI_Real8, owner(i), comm, ierr) |
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End Do |
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! ----------------------------------------------------------------------- |
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End Subroutine getrs |