Line data    Source code

       1             : MODULE m_spgrot
       2             :     ! Perform the space group operations of the system.
       3             :     ! I.e. construct all G vectors (and optionally phases) of a star from
       4             :     ! its representative reciprocal lattice vector k in internal coordinates.
       5             : 
       6             : CONTAINS
       7    27565992 :     SUBROUTINE spgrot(nop, symor, mrot, tau, invtab, k, kr, phas)
       8             : 
       9             :         USE m_constants
      10             : 
      11             :         IMPLICIT NONE
      12             : 
      13             :         ! Scalar arguments:
      14             :         INTEGER, INTENT(IN)  :: nop
      15             :         LOGICAL, INTENT(IN)  :: symor
      16             : 
      17             :         ! Array arguments:
      18             :         INTEGER, INTENT(IN)  :: k(:), mrot(:,:, :), invtab(:)
      19             :         REAL,    INTENT(IN)  :: tau(:,:)
      20             : 
      21             :         INTEGER,           INTENT(OUT) :: kr(:,:)
      22             :         COMPLEX, OPTIONAL, INTENT(OUT) :: phas(:) ! Could be complex!
      23             : 
      24             :         ! Local scalars:
      25             :         INTEGER :: n, ni
      26             : 
      27   181677748 :         DO n = 1, nop
      28             :             ! Construct \vec{G}_{op}^T = \vec{G}_{star}^T \cdot \mat{R}_{op}
      29  2493277844 :             kr(:, n) = matmul(k, mrot(:, :, n))
      30             :         END DO
      31             : 
      32    27565992 :         IF (.NOT.PRESENT(phas)) RETURN
      33             : 
      34    13560549 :         IF (symor) THEN
      35   125029100 :             phas(:) = 1.0
      36             :         ELSE
      37     3000609 :             DO n = 1,nop
      38     2774080 :                 ni = invtab(n)
      39             :                 ! Construct e^{-i * \vec{G}_{op}^T \cdot \vec{\tau}_{op}}
      40             :                 phas(n) = exp( -ImagUnit * tpi_const &
      41    11322849 :                       & * dot_product(real(kr(:, n)), tau(:, ni)) )
      42             :             END DO
      43             :         END IF
      44             : 
      45             :     END SUBROUTINE spgrot
      46             : END MODULE m_spgrot