Test for Lapack DGESVDX with RANGE='I'

testSVD.f

      PROGRAM testSVD
      IMPLICIT NONE

      INTEGER            M, N, LDA, LDU, LDVT, NS, LWORK, INFO
      PARAMETER        ( M = 5, N = 5, LDA = 10, LDU = 10, LDVT = 10 )

      INTEGER            IWORK( 12*MIN(M,N) )
      DOUBLE PRECISION   A( LDA, N ), S( MIN(M,N) ),
     $                   U( LDU, N ), VT( LDVT, N ), WORK( 2000 )

      EXTERNAL           SGGQRCS

      CALL DGESVDX( 'V', 'V', 'I', M, N, A, LDA, WORK(1), WORK(1),
     $               1, 5, NS, S, U, LDU, VT, LDVT,
     $               WORK, -1, IWORK, INFO )
      LWORK = INT(WORK(1))
      WRITE(*,*) "LWORK = ", LWORK

      A = 0.0
      A(1,1) = 1.0D0
      A(2,2) = 2.0D0
      A(3,3) = 3.0D0
      A(4,4) = 4.0D0
      A(5,5) = 5.0D0

      CALL DGESVDX( 'V', 'V', 'I', M, N, A, LDA, WORK(1), WORK(1),
     $               2, 4, NS, S, U, LDU, VT, LDVT,
     $               WORK, LWORK, IWORK, INFO )

      WRITE(*,*) "NS = ", NS
      WRITE(*,*) "S = ", S

      END PROGRAM testSVD