NAG Library Manual, Mark 28.3
```    Program f11jc_p0w_fe

!     F11JC_P0W_F Example Program Text

!     Mark 28.3 Release. NAG Copyright 2022.

!     .. Use Statements ..
Use iso_c_binding, Only: c_ptr
Use nag_library, Only: nag_wp
!     .. Implicit None Statement ..
Implicit None
!     .. Parameters ..
Integer, Parameter               :: nin = 5, nout = 6
!     .. Local Scalars ..
Real (Kind=nag_wp)               :: dscale, dtol, rnorm, tol
Integer                          :: i, ifail, itn, la, lfill, liwork,    &
lwork, maxitn, n, nnz, nnzc, npivm
Character (6)                    :: method
Character (1)                    :: mic, pstrat
!     .. Local Arrays ..
Real (Kind=nag_wp), Allocatable  :: a(:), work(:), x(:), y(:)
Integer, Allocatable             :: icol(:), ipiv(:), irow(:), istr(:),  &
iwork(:)
!     .. Executable Statements ..
Write (nout,*) 'F11JC_P0W_F Example Program Results'
!     Skip heading in data file

!     Read order of matrix and number of nonzero entries

la = 3*nnz
liwork = 2*la + 7*n + 1
lwork = 6*n + 120

Allocate (a(la),x(n),y(n),work(lwork),icol(la),ipiv(n),irow(la),         &
istr(n+1),iwork(liwork))

Do i = 1, nnz
End Do

!     Read initial approximation to solution

!     Calculate incomplete Cholesky factorization
ifail = 0
pstrat,ipiv,istr,nnzc,npivm,iwork,liwork,ifail)

!     Solve Ax = b using F11JC_P0W_F
ifail = 0
maxitn,x,rnorm,itn,work,lwork,ifail)

Write (nout,99999) 'Converged in', itn, ' iterations'
Write (nout,99998) 'Final residual norm =', rnorm

!     Output results
Write (nout,*) ' Solution of linear system'
Write (nout,99997)(x(i),i=1,n)

99999 Format (1X,A,I10,A)
99998 Format (1X,A,1P,E16.3)
99997 Format (1X,1P,E16.4)
End Program f11jc_p0w_fe
```