NAG Library Manual, Mark 29.2
Interfaces:  FL   CL   CPP   AD 

NAG FL Interface Introduction
Example description
    Program m01edfe

!     M01EDF Example Program Text

!     Mark 29.2 Release. NAG Copyright 2023.

!     .. Use Statements ..
      Use nag_library, Only: m01daf, m01edf, nag_wp, x04daf
!     .. Implicit None Statement ..
      Implicit None
!     .. Parameters ..
      Integer, Parameter               :: nin = 5, nout = 6
!     .. Local Scalars ..
      Integer                          :: i, ifail, j, k, m1, m2, n
      Character (30)                   :: string
!     .. Local Arrays ..
      Complex (Kind=nag_wp), Allocatable :: cm(:,:)
      Real (Kind=nag_wp), Allocatable  :: cmod(:)
      Integer, Allocatable             :: irank(:)
!     .. Intrinsic Procedures ..
      Intrinsic                        :: abs
!     .. Executable Statements ..
      Write (nout,*) 'M01EDF Example Program Results'
      Flush (nout)

!     Skip heading in data file
      Read (nin,*)

      Read (nin,*) m2, n, k

      If (k<1 .Or. k>n) Then
        Go To 100
      End If

      Allocate (cm(m2,n),cmod(m2),irank(m2))

      m1 = 1

      Do i = m1, m2
        Read (nin,*)(cm(i,j),j=1,n)
      End Do

!     Calculate the moduli of the elements in the K-th column.

      Do i = m1, m2
        cmod(i) = abs(cm(i,k))
      End Do

!     Rearrange the rows so that the elements in the K-th column
!     are in ascending order of modulus.

      ifail = 0
      Call m01daf(cmod,m1,m2,'Ascending',irank,ifail)

!     Rearrange each column into the order specified by IRANK.

      Do j = 1, n

        ifail = 0
        Call m01edf(cm(m1,j),m1,m2,irank,ifail)

      End Do

!     Print the results.

      Write (nout,*)
      Write (string,99999) 'Matrix sorted on column', k
      Flush (nout)

      ifail = 0
      Call x04daf('General',' ',m2-m1+1,n,cm(m1,1),m2,string,ifail)

100   Continue

99999 Format (1X,A,I3)
    End Program m01edfe