計算ルーチン: 複素三角行列の逆行列

ZTRTRI Example Program Data
  4                                                       :Value of N
  'L'                                                     :Value of UPLO
 ( 4.78, 4.56)
 ( 2.00,-0.30) (-4.11, 1.25)
 ( 2.89,-1.34) ( 2.36,-4.25) ( 4.15, 0.80)
 (-1.89, 1.15) ( 0.04,-3.69) (-0.02, 0.46) ( 0.33,-0.26)  :End of matrix A

 ZTRTRI Example Program Results

 Inverse
                    1                 2                 3                 4
 1  ( 0.1095,-0.1045)
 2  ( 0.0582,-0.0411) (-0.2227,-0.0677)
 3  ( 0.0032, 0.1905) ( 0.1538,-0.2192) ( 0.2323,-0.0448)
 4  ( 0.7602, 0.2814) ( 1.6184,-1.4346) ( 0.1289,-0.2250) ( 1.8697, 1.4731)

    Program ztrtri_example

!     ZTRTRI Example Program Text

!     Copyright 2017, Numerical Algorithms Group Ltd. http://www.nag.com

!     .. Use Statements ..
      Use lapack_example_aux, Only: nagf_file_print_matrix_complex_gen_comp
      Use lapack_interfaces, Only: ztrtri
      Use lapack_precision, Only: dp
!     .. Implicit None Statement ..
      Implicit None
!     .. Parameters ..
      Integer, Parameter :: nin = 5, nout = 6
      Character (1), Parameter :: diag = 'N'
!     .. Local Scalars ..
      Integer :: i, ifail, info, lda, n
      Character (1) :: uplo
!     .. Local Arrays ..
      Complex (Kind=dp), Allocatable :: a(:, :)
      Character (1) :: clabs(1), rlabs(1)
!     .. Executable Statements ..
      Write (nout, *) 'ZTRTRI Example Program Results'
!     Skip heading in data file
      Read (nin, *)
      Read (nin, *) n
      lda = n
      Allocate (a(lda,n))

!     Read A from data file

      Read (nin, *) uplo
      If (uplo=='U') Then
        Read (nin, *)(a(i,i:n), i=1, n)
      Else If (uplo=='L') Then
        Read (nin, *)(a(i,1:i), i=1, n)
      End If

!     Compute inverse of A
      Call ztrtri(uplo, diag, n, a, lda, info)

!     Print inverse

      Write (nout, *)
      Flush (nout)

!     ifail: behaviour on error exit
!             =0 for hard exit, =1 for quiet-soft, =-1 for noisy-soft
      ifail = 0
      Call nagf_file_print_matrix_complex_gen_comp(uplo, diag, n, n, a, lda, &
        'Bracketed', 'F7.4', 'Inverse', 'Integer', rlabs, 'Integer', clabs, &
        80, 0, ifail)

    End Program