lapack.f90

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MODULE lapack
  
  USE kinds
  
  IMPLICIT NONE

  INTERFACE

    SUBROUTINE dgesv(N, NRHS, A, LDA, IPIV, B, LDB, INFO )
      USE kinds
      INTEGER(INTG), INTENT(IN) :: N
      INTEGER(INTG), INTENT(IN) :: NRHS
      INTEGER(INTG), INTENT(IN) :: LDA
      REAL(DP), INTENT(INOUT) :: A(lda,*)
      INTEGER(INTG), INTENT(OUT) :: IPIV(*)
      INTEGER(INTG), INTENT(IN) :: LDB
      REAL(DP), INTENT(INOUT) :: B(ldb,*)
      INTEGER(INTG), INTENT(OUT) :: INFO
    END SUBROUTINE dgesv

    ! DGESVD - compute the singular value decomposition (SVD) of a
    !  real M-by-N matrix A, optionally computing the left and/or
    !  right singular vectors
    SUBROUTINE dgesvd( JOBU, JOBVT, M, N, A, LDA, S, U, LDU, VT, LDVT, WORK, LWORK, INFO )
      USE kinds
      CHARACTER(1) :: JOBU ! Specifies options for computing all or part of the matrix U (options: A,S,O,N)
      CHARACTER(1) :: JOBVT ! Specifies options for computing all or part of the matrix V**T (options: A,S,O,N)
      INTEGER(INTG), INTENT(IN) :: M ! Number of rows in A
      INTEGER(INTG), INTENT(IN) :: N ! Number of columns in A
      REAL(DP), INTENT(INOUT) :: A(lda,*) ! The matrix to perform the SVD on
      INTEGER(INTG), INTENT(IN) :: LDA ! Leading dimension of A
      REAL(DP), INTENT(OUT) :: S(min(m,n)) ! Singular values of A, sorted S(i) >= S(i+1)
      REAL(DP), INTENT(OUT) :: U(ldu,*) ! If JOBU = 'A', U contains the M-by-M orthogonal matrix U
      INTEGER(INTG), INTENT(IN) :: LDU ! Leading dimension of U
      REAL(DP), INTENT(OUT) :: VT(ldvt,n) ! If JOBVT = 'A', VT contains the N-by-N orthogonal matrix V**T
      INTEGER(INTG), INTENT(IN) :: LDVT ! The leading dimension of the array VT
      REAL(DP), INTENT(INOUT) :: WORK(*) ! On exit, if INFO = 0, WORK(1) returns the optimal LWORK
      INTEGER(INTG), INTENT(IN) :: LWORK ! The dimension of the array WORK
      INTEGER(INTG), INTENT(OUT) :: INFO ! 0 if successful exit; < 0 if INFO = -i (the i-th argument had an illegal value); > 0 if DBDSQR did not converge
    END SUBROUTINE dgesvd
    
    SUBROUTINE dsyev( JOBZ, UPLO, N, A, LDA, W, WORK, LWORK, INFO )
      USE kinds
      CHARACTER(LEN=1), INTENT(IN) :: JOBZ
      CHARACTER(LEN=1), INTENT(IN) :: UPLO
      INTEGER(INTG), INTENT(IN) :: N
      REAL(DP), INTENT(INOUT) :: A(lda,n)
      INTEGER(INTG), INTENT(IN) :: LDA
      REAL(DP), INTENT(OUT) :: W(n)
      REAL(DP), INTENT(OUT) :: WORK(lwork)
      INTEGER(INTG), INTENT(IN) :: LWORK
      INTEGER(INTG), INTENT(OUT) :: INFO
    END SUBROUTINE dsyev
      
  END INTERFACE

END MODULE lapack