PROGRAM nag_mat_inv_ex26

      ! Example Program Text for nag_mat_inv
      ! NAG fl90, Release 4. NAG Copyright 2000.

      ! .. Use Statements ..
      USE nag_mat_inv, ONLY : nag_tri_mat_inv
      USE nag_examples_io, ONLY : nag_std_out, nag_std_in
      USE nag_write_mat, ONLY : nag_write_tri_mat
      ! .. Implicit None Statement ..
      IMPLICIT NONE
      ! .. Intrinsic Functions ..
      INTRINSIC KIND
      ! .. Parameters ..
      INTEGER, PARAMETER :: wp = KIND(1.0D0)
      ! .. Local Scalars ..
      INTEGER :: i, j, n
      CHARACTER (1) :: uplo
      ! .. Local Arrays ..
      REAL (wp), ALLOCATABLE :: a(:,:)
      ! .. Executable Statements ..
      WRITE (nag_std_out,*) 'Example Program Results for nag_mat_inv_ex26'
      WRITE (nag_std_out,*)

      READ (nag_std_in,*)          ! Skip heading in data file
      READ (nag_std_in,*) n
      READ (nag_std_in,*) uplo

      ALLOCATE (a(n,n))            ! Allocate storage

      SELECT CASE (uplo)
      CASE ('L','l')
        DO i = 1, n
          READ (nag_std_in,*) (a(i,j),j=1,i)
        END DO
      CASE ('U','u')
        DO i = 1, n
          READ (nag_std_in,*) (a(i,j),j=i,n)
        END DO
      END SELECT

      CALL nag_tri_mat_inv(uplo,a)

      CALL nag_write_tri_mat(uplo,a,format='F10.4',title= &
       'Inverse matrix  (triangular)')

      DEALLOCATE (a)               ! Deallocate storage

    END PROGRAM nag_mat_inv_ex26