! E04STF Example Program Text
! Mark 30.0 Release. NAG Copyright 2024.
! NLP example: linear objective + linear constraint + nonlinear constraint.
! For illustrative purposes, the linear objective will be treated as a
! nonlinear function to show the usage of objfun and objgrd user call-backs.
Module e04stfe_mod
! Derived type my_data serves to demonstrate how to use the cpuser
! communication argument in callbacks.
! .. Use Statements ..
Use nag_library, Only: nag_wp
! .. Implicit None Statement ..
Implicit None
! .. Accessibility Statements ..
Private
Public :: confun, congrd, hess, objfun, objgrd
! .. Derived Type Definitions ..
Type, Public :: my_data
Real (Kind=nag_wp), Allocatable :: coeffs(:)
End Type my_data
Contains
Subroutine objfun(nvar,x,fx,inform,iuser,ruser,cpuser)
! .. Use Statements ..
Use, Intrinsic :: iso_c_binding, Only: c_f_pointer, &
c_ptr
Use nag_library, Only: f06eaf
! .. Scalar Arguments ..
Type (c_ptr), Intent (In) :: cpuser
Real (Kind=nag_wp), Intent (Out) :: fx
Integer, Intent (Inout) :: inform
Integer, Intent (In) :: nvar
! .. Array Arguments ..
Real (Kind=nag_wp), Intent (Inout) :: ruser(*)
Real (Kind=nag_wp), Intent (In) :: x(nvar)
Integer, Intent (Inout) :: iuser(*)
! .. Local Scalars ..
Type (my_data), Pointer :: data
! .. Executable Statements ..
Call c_f_pointer(cptr=cpuser,fptr=data)
fx = f06eaf(4,x,1,data%coeffs,1)
inform = 0
Return
End Subroutine objfun
Subroutine objgrd(nvar,x,nnzfd,fdx,inform,iuser,ruser,cpuser)
! .. Use Statements ..
Use, Intrinsic :: iso_c_binding, Only: c_f_pointer, &
c_ptr
! .. Scalar Arguments ..
Type (c_ptr), Intent (In) :: cpuser
Integer, Intent (Inout) :: inform
Integer, Intent (In) :: nnzfd, nvar
! .. Array Arguments ..
Real (Kind=nag_wp), Intent (Inout) :: fdx(nnzfd), ruser(*)
Real (Kind=nag_wp), Intent (In) :: x(nvar)
Integer, Intent (Inout) :: iuser(*)
! .. Local Scalars ..
Type (my_data), Pointer :: data
! .. Executable Statements ..
Call c_f_pointer(cptr=cpuser,fptr=data)
fdx(1:nnzfd) = data%coeffs(1:nnzfd)
inform = 0
Return
End Subroutine objgrd
Subroutine confun(nvar,x,ncnln,gx,inform,iuser,ruser,cpuser)
! .. Use Statements ..
Use, Intrinsic :: iso_c_binding, Only: c_ptr
! .. Scalar Arguments ..
Type (c_ptr), Intent (In) :: cpuser
Integer, Intent (Inout) :: inform
Integer, Intent (In) :: ncnln, nvar
! .. Array Arguments ..
Real (Kind=nag_wp), Intent (Out) :: gx(ncnln)
Real (Kind=nag_wp), Intent (Inout) :: ruser(*)
Real (Kind=nag_wp), Intent (In) :: x(nvar)
Integer, Intent (Inout) :: iuser(*)
! .. Intrinsic Procedures ..
Intrinsic :: sqrt
! .. Executable Statements ..
inform = 0
gx(1) = 12.0_nag_wp*x(1) + 11.9_nag_wp*x(2) + 41.8_nag_wp*x(3) + &
52.1_nag_wp*x(4) - 1.645_nag_wp*sqrt(.28_nag_wp*x(1)**2+.19_nag_wp*x &
(2)**2+20.5_nag_wp*x(3)**2+.62_nag_wp*x(4)**2)
Return
End Subroutine confun
Subroutine congrd(nvar,x,nnzgd,gdx,inform,iuser,ruser,cpuser)
! .. Use Statements ..
Use, Intrinsic :: iso_c_binding, Only: c_ptr
! .. Scalar Arguments ..
Type (c_ptr), Intent (In) :: cpuser
Integer, Intent (Inout) :: inform
Integer, Intent (In) :: nnzgd, nvar
! .. Array Arguments ..
Real (Kind=nag_wp), Intent (Inout) :: gdx(nnzgd), ruser(*)
Real (Kind=nag_wp), Intent (In) :: x(nvar)
Integer, Intent (Inout) :: iuser(*)
! .. Local Scalars ..
Real (Kind=nag_wp) :: tmp
! .. Intrinsic Procedures ..
Intrinsic :: sqrt
! .. Executable Statements ..
inform = 0
tmp = sqrt(0.62_nag_wp*x(4)**2+20.5_nag_wp*x(3)**2+ &
0.19_nag_wp*x(2)**2+0.28_nag_wp*x(1)**2)
gdx(1) = (12.0_nag_wp*tmp-0.4606_nag_wp*x(1))/tmp
gdx(2) = (11.9_nag_wp*tmp-0.31255_nag_wp*x(2))/tmp
gdx(3) = (41.8_nag_wp*tmp-33.7225_nag_wp*x(3))/tmp
gdx(4) = (52.1_nag_wp*tmp-1.0199_nag_wp*x(4))/tmp
Return
End Subroutine congrd
Subroutine hess(nvar,x,ncnln,idf,sigma,lambda,nnzh,hx,inform,iuser, &
ruser,cpuser)
! .. Use Statements ..
Use, Intrinsic :: iso_c_binding, Only: c_ptr
! .. Scalar Arguments ..
Type (c_ptr), Intent (In) :: cpuser
Real (Kind=nag_wp), Intent (In) :: sigma
Integer, Intent (In) :: idf, ncnln, nnzh, nvar
Integer, Intent (Inout) :: inform
! .. Array Arguments ..
Real (Kind=nag_wp), Intent (Inout) :: hx(nnzh), ruser(*)
Real (Kind=nag_wp), Intent (In) :: lambda(ncnln), x(nvar)
Integer, Intent (Inout) :: iuser(*)
! .. Local Scalars ..
Real (Kind=nag_wp) :: tmp
! .. Intrinsic Procedures ..
Intrinsic :: sqrt
! .. Executable Statements ..
inform = -1
hx = 0.0_nag_wp
Select Case (idf)
Case (0)
inform = 0
Case (1,-1)
tmp = sqrt(0.62_nag_wp*x(4)**2+20.5_nag_wp*x(3)**2+ &
0.19_nag_wp*x(2)**2+0.28_nag_wp*x(1)**2)
tmp = tmp*(x(4)**2+33.064516129032258064_nag_wp*x(3)**2+ &
0.30645161290322580645_nag_wp*x(2)**2+ &
0.45161290322580645161_nag_wp*x(1)**2)
! 1,1..4
hx(1) = (-0.4606_nag_wp*x(4)**2-15.229516129032258064_nag_wp*x(3)**2 &
-0.14115161290322580645_nag_wp*x(2)**2)/tmp
hx(2) = (0.14115161290322580645_nag_wp*x(1)*x(2))/tmp
hx(3) = (15.229516129032258064_nag_wp*x(1)*x(3))/tmp
hx(4) = (0.4606_nag_wp*x(1)*x(4))/tmp
! 2,2..4
hx(5) = (-0.31255_nag_wp*x(4)**2-10.334314516129032258_nag_wp*x(3)** &
2-0.14115161290322580645_nag_wp*x(1)**2)/tmp
hx(6) = (10.334314516129032258_nag_wp*x(2)*x(3))/tmp
hx(7) = (0.31255_nag_wp*x(2)*x(4))/tmp
! 3,3..4
hx(8) = (-33.7225_nag_wp*x(4)**2-10.334314516129032258_nag_wp*x(2)** &
2-15.229516129032258065_nag_wp*x(1)**2)/tmp
hx(9) = (33.7225_nag_wp*x(3)*x(4))/tmp
! 4,4
hx(10) = (-33.7225_nag_wp*x(3)**2-0.31255_nag_wp*x(2)**2- &
0.4606_nag_wp*x(1)**2)/tmp
If (idf==-1) Then
hx = lambda(1)*hx
End If
inform = 0
End Select
Return
End Subroutine hess
End Module e04stfe_mod
Program e04stfe
! .. Use Statements ..
Use e04stfe_mod, Only: confun, congrd, hess, my_data, objfun, objgrd
Use, Intrinsic :: iso_c_binding, Only: c_loc, &
c_null_ptr, c_ptr
Use nag_library, Only: e04raf, e04rgf, e04rhf, e04rjf, e04rkf, e04rlf, &
e04rzf, e04stf, e04stu, e04zmf, nag_wp
! .. Implicit None Statement ..
Implicit None
! .. Parameters ..
Real (Kind=nag_wp), Parameter :: bigbnd = 1.0E20_nag_wp
Integer, Parameter :: nout = 6
! .. Local Scalars ..
Type (c_ptr) :: cpuser, handle
Type (my_data), Pointer :: data
Real (Kind=nag_wp) :: lmtest
Integer :: i, idlc, idx, ifail, j, nclin, &
ncnln, nnzfd, nnzgd, nnzu, nvar
Character (6) :: rlmtest
! .. Local Arrays ..
Real (Kind=nag_wp) :: b(8), bl(4), bu(4), lambda(7), &
linbl(2), linbu(2), nlnbl(1), &
nlnbu(1), rinfo(100), ruser(1), &
stats(100), x(4)
Real (Kind=nag_wp), Allocatable :: fdx(:), gdx(:), u(:)
Integer :: icolb(8), icolgd(4), icolh(10), &
idxfd(4), irowb(8), irowgd(4), &
irowh(10), iuser(1)
! .. Intrinsic Procedures ..
Intrinsic :: abs, int, merge
! .. Executable Statements ..
Write (nout,*) 'E04STF Example Program Results'
Write (nout,*)
Flush (nout)
ifail = 0
handle = c_null_ptr
! Problem size
nvar = 4
! Counter for Lagrange multipliers
nnzu = 0
! Objective gradient nonzero elements quantity
nnzfd = 4
! Constraint jacobian nonzero elements quantity
nnzgd = 4
! Initialize handle
Call e04raf(handle,nvar,ifail)
Allocate (data)
Allocate (data%coeffs(nvar),fdx(nvar),gdx(nnzgd))
cpuser = c_loc(data)
data%coeffs(:) = (/24.55_nag_wp,26.75_nag_wp,39.00_nag_wp,40.50_nag_wp/)
idxfd(1:nnzfd) = (/1,2,3,4/)
! Add linear function as a nonlinear objective
Call e04rgf(handle,nnzfd,idxfd,ifail)
! Add simple bounds (x>=0).
bl(1:4) = 0.0_nag_wp
bu(1:4) = bigbnd
Call e04rhf(handle,nvar,bl,bu,ifail)
! Specify the amount of Lagrange mult. required
nnzu = nnzu + 2*nvar
! Add two linear constraints
nclin = 2
linbl(1:2) = (/5.0_nag_wp,1.0_nag_wp/)
linbu(1:2) = (/bigbnd,1.0_nag_wp/)
irowb(1:8) = (/1,1,1,1,2,2,2,2/)
icolb(1:8) = (/1,2,3,4,1,2,3,4/)
b(1:8) = (/2.3_nag_wp,5.6_nag_wp,11.1_nag_wp,1.3_nag_wp,1.0_nag_wp, &
1.0_nag_wp,1.0_nag_wp,1.0_nag_wp/)
idlc = 0
Call e04rjf(handle,nclin,linbl,linbu,nclin*nvar,irowb,icolb,b,idlc, &
ifail)
! Update the Lagrange mult. count
nnzu = nnzu + 2*nclin
! Add one nonlinear constraint
ncnln = 1
nlnbl(1:ncnln) = (/21.0_nag_wp/)
nlnbu(1:ncnln) = (/bigbnd/)
irowgd(1:nnzgd) = (/1,1,1,1/)
icolgd(1:nnzgd) = (/1,2,3,4/)
Call e04rkf(handle,ncnln,nlnbl,nlnbu,nnzgd,irowgd,icolgd,ifail)
! Update the Lagrange mult. count and allocate space for storage
nnzu = nnzu + 2*ncnln
Allocate (u(nnzu))
! Define dense structure of the Hessian
idx = 1
Do i = 1, nvar
Do j = i, nvar
icolh(idx) = j
irowh(idx) = i
idx = idx + 1
End Do
End Do
! Hessian of nonlinear constraint
Call e04rlf(handle,1,idx-1,irowh,icolh,ifail)
Call e04rlf(handle,0,idx-1,irowh,icolh,ifail)
! Specify initial starting point
x(1:nvar) = (/1.0_nag_wp,1.0_nag_wp,1.0_nag_wp,1.0_nag_wp/)
! Set print level for iteration output
Call e04zmf(handle,'Print Level = 0',ifail)
Call e04zmf(handle,'Outer Iteration Limit = 26',ifail)
Call e04zmf(handle,'Stop Tolerance 1 = 2.5e-8',ifail)
! Call solver
ifail = -1
Call e04stf(handle,objfun,objgrd,confun,congrd,hess,e04stu,nvar,x,nnzu, &
u,rinfo,stats,iuser,ruser,cpuser,ifail)
If (ifail==0) Then
Write (nout,99999)
Write (nout,99994)(i,x(i),i=1,nvar)
Write (nout,99998)
Write (nout,99991)(i,u(2*i-1),i,u(2*i),i=1,nvar)
Write (nout,99996)
Write (nout,99992)(i,u(2*i-1+2*nvar),i,u(2*i+2*nvar),i=1,nclin)
Write (nout,99995)
Write (nout,99992)(i,u(2*i-1+2*nvar+2*nclin),i,u(2*i+2*nvar+2*nclin), &
i=1,ncnln)
! Check of Lagrange multipliers (complementariety)
! Gradient of the objective (also available in data%coeffs(1:nnzfd))
Call objgrd(nvar,x,nnzfd,fdx,ifail,iuser,ruser,cpuser)
! Gradient of the linear constraints is already available in
! irowb(1:8), icolb(1:8) and b(1:8)
! Gradient of the nonlinear constraint
Call congrd(nvar,x,nnzgd,gdx,ifail,iuser,ruser,cpuser)
! Obtain the multipliers with correct sign
! 4 bound constraints, 2 linear constraints, and 1 nonlinear constraint
Do i = 1, 7
lambda(i) = u(2*i) - u(2*i-1)
End Do
! lambda (1..4) mult. related to bounds
! lambda (5..6) mult. related to linear constraints
! lambda (7) mult. related to the nonlinear constraint
Write (nout,99997)
Do i = 1, 4
lmtest = fdx(i) + lambda(i) + lambda(5)*b(i) + lambda(6)*b(4+i) + &
lambda(7)*gdx(i)
rlmtest = merge('Ok ','Failed',abs(lmtest)<2.5E-8_nag_wp)
Write (nout,99993) i, lmtest, rlmtest
End Do
Write (nout,99990) rinfo(1)
Write (nout,99989) rinfo(2)
Write (nout,99988) rinfo(3)
Write (nout,99987) rinfo(4)
Write (nout,99986) rinfo(5)
Write (nout,99985) int(stats(1))
Write (nout,99984) int(stats(19))
Write (nout,99983) int(stats(5))
Write (nout,99982) int(stats(20))
Write (nout,99981) int(stats(21))
Write (nout,99980) int(stats(4))
End If
Flush (nout)
! Release all memory
Call e04rzf(handle,ifail)
Deallocate (data%coeffs,u,fdx,gdx)
Deallocate (data)
99999 Format (/,'Variables')
99998 Format ('Variable bound Lagrange multipliers')
99997 Format ('Stationarity test for Lagrange multipliers')
99996 Format ('Linear constraints Lagrange multipliers')
99995 Format ('Nonlinear constraints Lagrange multipliers')
99994 Format (5X,'x(',I10,')',17X,'=',1P,E16.2)
99993 Format (4X,'lx(',I10,')',17X,'=',1P,E16.2,5X,A6)
99992 Format (4X,'zL(',I10,')',17X,'=',1P,E16.2,/,4X,'zU(',I10,')',17X,'=',1P, &
E16.2)
99991 Format (4X,'zL(',I10,')',17X,'=',1P,E16.2,/,4X,'zU(',I10,')',17X,'=',1P, &
E16.2)
99990 Format (/,'At solution, Objective minimum =',1P,E16.4)
99989 Format (' Constraint violation =',1P,6X,E10.2)
99988 Format (' Dual infeasibility =',1P,6X,E10.2)
99987 Format (' Complementarity =',1P,6X,E10.2)
99986 Format (' KKT error =',1P,6X,E10.2)
99985 Format (' after iterations :',I11)
99984 Format (' after objective evaluations :',I11)
99983 Format (' after objective gradient evaluations :',I11)
99982 Format (' after constraint evaluations :',I11)
99981 Format (' after constraint gradient evaluations :',I11)
99980 Format (' after hessian evaluations :',I11)
End Program e04stfe