NAG Library Manual, Mark 30
Program f11jafe

!     F11JAF Example Program Text

!     Mark 30.0 Release. NAG Copyright 2024.

!     .. Use Statements ..
Use nag_library, Only: f11jaf, nag_wp
!     .. Implicit None Statement ..
Implicit None
!     .. Parameters ..
Integer, Parameter               :: nin = 5, nout = 6
!     .. Local Scalars ..
Real (Kind=nag_wp)               :: dscale, dtol
Integer                          :: i, ifail, la, lfill, liwork, n, nnz, &
nnzc, npivm
Character (1)                    :: mic, pstrat
!     .. Local Arrays ..
Real (Kind=nag_wp), Allocatable  :: a(:)
Integer, Allocatable             :: icol(:), ipiv(:), irow(:), istr(:),  &
iwork(:)
!     .. Executable Statements ..
Write (nout,*) 'F11JAF Example Program Results'
!     Skip heading in data file

la = 2*nnz
liwork = 2*la + 7*n + 1
Allocate (a(la),icol(la),ipiv(n),irow(la),istr(n+1),iwork(liwork))

Do i = 1, nnz
End Do

!     Calculate incomplete Cholesky factorization

!     ifail: behaviour on error exit
!             =0 for hard exit, =1 for quiet-soft, =-1 for noisy-soft
ifail = 0
Call f11jaf(n,nnz,a,la,irow,icol,lfill,dtol,mic,dscale,pstrat,ipiv,istr, &
nnzc,npivm,iwork,liwork,ifail)

!     Output original matrix

Write (nout,*) ' Original Matrix'
Write (nout,99997) 'N     =', n
Write (nout,99997) 'NNZ   =', nnz
Do i = 1, nnz
Write (nout,99999) i, a(i), irow(i), icol(i)
End Do
Write (nout,*)

!     Output details of the factorization

Write (nout,*) ' Factorization'
Write (nout,99997) 'N     =', n
Write (nout,99997) 'NNZ   =', nnzc
Write (nout,99997) 'NPIVM =', npivm
Do i = nnz + 1, nnz + nnzc
Write (nout,99999) i, a(i), irow(i), icol(i)
End Do
Write (nout,*)

Write (nout,*) '      I     IPIV(I)'
Do i = 1, n
Write (nout,99998) i, ipiv(i)
End Do

99999 Format (1X,I8,E16.4,2I8)
99998 Format (1X,2I8)
99997 Format (1X,A,I16)
End Program f11jafe