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40 lines
737 B
Fortran
40 lines
737 B
Fortran
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! Vect to antisymmetric matrix using mat_to_vec_index
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! Vector to antisymmetric matrix transformation using mat_to_vec_index
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! subroutine.
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! Can be done in OMP (for the first part and with omp critical for the second)
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subroutine vec_to_mat_v2(n,m,v_x,m_x)
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!BEGIN_DOC
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! Vector to antisymmetric matrix
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!END_DOC
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implicit none
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integer, intent(in) :: n,m
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double precision, intent(in) :: v_x(n)
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double precision, intent(out) :: m_x(m,m)
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integer :: i,j,k
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! 1D -> 2D lower diagonal
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m_x = 0d0
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do j = 1, m - 1
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do i = j + 1, m
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call mat_to_vec_index(i,j,k)
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m_x(i,j) = v_x(k)
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enddo
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enddo
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! Antisym
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do i = 1, m - 1
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do j = i + 1, m
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m_x(i,j) = - m_x(j,i)
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enddo
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enddo
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end
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