!! Module to put all of newuoa-Fortran77 code of Professor Michael J.D. Powell
!! in one file and
!! provide a Subroutine with a
!! Fortran 95 interface for the top level routine.
!! Newuoa is an optimization routine for unconstrained optimization
!! without using derivatives of the objective function.
!! Newuoa consideres an objective function evaluation to be expensive.
!! This module is distributed under the same terms as Professor Michael Powells
!! newuoa. Basically GNU and you can use it freely.
!! Adapted by Tian Lu (sobereva@sina.com) at 2020-Feb-29
MODULE newuoa_module
contains
!! The routine minimizes CALFUN in X such that the function is
!! minimized without using derivatives.
!! - SUBROUTINE CALFUN (i_X,o_F) is the function to be minimized without using derivatives.
!! It must set o_F (output) to
!! the value of the objective function for the (input)
!! variables i_X(1),i_X(2),...,i_X(N).
!! - X: on entry initial x where search starts. On exit best found
!! vector x that minimizes CALFUN.
!! - RHOBEG and RHOEND must be set to the initial and final values of a trust
!! region radius, so both must be positive with RHOEND<=RHOBEG. Typically
!! RHOBEG should be about one tenth of the greatest expected change to a
!! variable, and RHOEND should indicate the accuracy that is required in
!! the final values of the variables.
!! - The value of IPRINT should be set to 0, 1, 2 or 3, which controls the
!! amount of printing. Specifically, there is no output if IPRINT=0 and
!! there is output only at the return if IPRINT=1. Otherwise, each new
!! value of RHO is printed, with the best vector of variables so far and
!! the corresponding value of the objective function. Further, each new
!! value of F with its variables are output if IPRINT=3.
!! - MAXFUN: maximal number of calls to CALFUN.
SUBROUTINE newuoa_min(CALFUN, X, RHOBEG, RHOEND, IPRINT, MAXFUN)
implicit none
interface
subroutine CALFUN(i_x, o_f)
real(kind=8), dimension(:) :: i_x
real(kind=8) :: o_f
end subroutine
end interface
real(kind=8), intent(inout), dimension(:) :: X
real(kind=8), intent(in) :: RHOBEG, RHOEND
integer, intent(in) :: IPRINT, MAXFUN
integer :: NPT, N
real(kind=8), dimension(:), allocatable :: W
N = size(X)
!! - NPT is the number of interpolation conditions. Its value must be in the
!! interval [N+2,(N+1)(N+2)/2] with N=size(X).
!! NPT=2*N+1 is usually appropriate
NPT = 2*N + 1
allocate( W( (NPT+13)*(NPT+N)+3*N*(N+3)/2 ) )
call NEWUOA( CALFUN,N,NPT,X,RHOBEG,RHOEND, &
IPRINT, MAXFUN, W )
deallocate( W )
END SUBROUTINE newuoa_min
SUBROUTINE NEWUOA(CALFUN,N,NPT,X,RHOBEG,RHOEND,IPRINT,MAXFUN,W)
implicit none
integer, intent(in) :: N, NPT, IPRINT, MAXFUN
real(kind=8), intent(inout) :: X(:), W(*)
real(kind=8), intent(in) :: RHOBEG,RHOEND
interface
subroutine CALFUN(i_x,o_f)
real(kind=8), dimension(:) :: i_x
real(kind=8) :: o_f
end subroutine
end interface
!local variables:
integer :: NP, NPTM, NDIM, IXB, IXO, IXN, IXP, IFV, IGQ, &
IHQ, IPQ, IBMAT, IZMAT, ID, IVL, IW
!
! This subroutine seeks the least value of a function of many variables,
! by a trust region method that forms quadratic models by interpolation.
! There can be some freedom in the interpolation conditions, which is
! taken up by minimizing the Frobenius norm of the change to the second
! derivative of the quadratic model, beginning with a zero matrix. The
! arguments of the subroutine are as follows.
! N must be set to the number of variables and must be at least two.
! NPT is the number of interpolation conditions. Its value must be in the
! interval [N+2,(N+1)(N+2)/2].
! Initial values of the variables must be set in X(1),X(2),...,X(N). They
! will be changed to the values that give the least calculated F.
! RHOBEG and RHOEND must be set to the initial and final values of a trust
! region radius, so both must be positive with RHOEND<=RHOBEG. Typically
! RHOBEG should be about one tenth of the greatest expected change to a
! variable, and RHOEND should indicate the accuracy that is required in
! the final values of the variables.
! The value of IPRINT should be set to 0, 1, 2 or 3, which controls the
! amount of printing. Specifically, there is no output if IPRINT=0 and
! there is output only at the return if IPRINT=1. Otherwise, each new
! value of RHO is printed, with the best vector of variables so far and
! the corresponding value of the objective function. Further, each new
! value of F with its variables are output if IPRINT=3.
! MAXFUN must be set to an upper bound on the number of calls of CALFUN.
! The array W will be used for working space. Its length must be at least
! (NPT+13)*(NPT+N)+3*N*(N+3)/2.
! SUBROUTINE CALFUN (X,F) must be provided by the user. It must set F to
! the value of the objective function for the variables X(1),X(2),...,X(N).
! Partition the working space array, so that different parts of it can be
! treated separately by the subroutine that performs the main calculation.
NP=N+1
NPTM=NPT-NP
IF (NPT .LT. N+2 .OR. NPT .GT. ((N+2)*NP)/2) THEN
PRINT 10
10 FORMAT (/4X,'Return from NEWUOA because NPT is not in', &
' the required interval')
GO TO 20
END IF
NDIM=NPT+N
IXB=1
IXO=IXB+N
IXN=IXO+N
IXP=IXN+N
IFV=IXP+N*NPT
IGQ=IFV+NPT
IHQ=IGQ+N
IPQ=IHQ+(N*NP)/2
IBMAT=IPQ+NPT
IZMAT=IBMAT+NDIM*N
ID=IZMAT+NPT*NPTM
IVL=ID+N
IW=IVL+NDIM
! The above settings provide a partition of W for subroutine NEWUOB.
! The partition requires the first NPT*(NPT+N)+5*N*(N+3)/2 elements of
! W plus the space that is needed by the last array of NEWUOB.
CALL NEWUOB(CALFUN, N,NPT,X,RHOBEG,RHOEND,IPRINT,MAXFUN,W(IXB), &
W(IXO),W(IXN),W(IXP),W(IFV),W(IGQ),W(IHQ),W(IPQ),W(IBMAT), &
W(IZMAT),NDIM,W(ID),W(IVL),W(IW))
20 RETURN
END SUBROUTINE NEWUOA
SUBROUTINE NEWUOB(CALFUN,N,NPT,X,RHOBEG,RHOEND,IPRINT,MAXFUN,XBASE, &
XOPT,XNEW,XPT,FVAL,GQ,HQ,PQ,BMAT,ZMAT,NDIM,D,VLAG,W)
implicit none
integer, intent(in) :: N, NPT, IPRINT,MAXFUN, NDIM
real(kind=8), intent(inout), dimension(:) :: X
real(kind=8), intent(in) :: RHOBEG, RHOEND
real(kind=8), intent(inout) :: XBASE(*), XOPT(*),XNEW(*), &
FVAL(*), GQ(*), HQ(*), PQ(*), D(*), VLAG(*), W(*)
real(kind=8), intent(inout) :: BMAT(NDIM,*),ZMAT(NPT,*), XPT(NPT,*)
interface
subroutine CALFUN(i_x,o_f)
real(kind=8), dimension(:) :: i_x
real(kind=8) :: o_f
end subroutine
end interface
!local variables
integer :: NP, NH,NPTM,NFTEST, NF, NFM, NFMM, ITEMP, JPT, IPT, &
IH, IDZ, ITEST, NFSAV, KNEW, I, IP, J, JP, K, KSAVE, &
KTEMP, KOPT
real(kind=8) :: HALF, ONE, TENTH, ZERO, RHOSQ, RECIP,RECIQ, XIPT, &
XJPT, FBEG, FOPT, RHO, DELTA, DIFFA, DIFFB, &
XOPTSQ, DSQ, DNORM, RATIO, TEMP, CRVMIN, TEMPQ, &
ALPHA, BETA, BSUM, DETRAT, DIFF, DIFFC, DISTSQ, &
DX, F, FSAVE, GISQ, GQSQ, HDIAG, SUM, SUMA, SUMB, &
DSTEP, SUMZ, VQUAD
! The arguments N, NPT, X, RHOBEG, RHOEND, IPRINT and MAXFUN are identical
! to the corresponding arguments in SUBROUTINE NEWUOA.
! XBASE will hold a shift of origin that should reduce the contributions
! from rounding errors to values of the model and Lagrange functions.
! XOPT will be set to the displacement from XBASE of the vector of
! variables that provides the least calculated F so far.
! XNEW will be set to the displacement from XBASE of the vector of
! variables for the current calculation of F.
! XPT will contain the interpolation point coordinates relative to XBASE.
! FVAL will hold the values of F at the interpolation points.
! GQ will hold the gradient of the quadratic model at XBASE.
! HQ will hold the explicit second derivatives of the quadratic model.
! PQ will contain the parameters of the implicit second derivatives of
! the quadratic model.
! BMAT will hold the last N columns of H.
! ZMAT will hold the factorization of the leading NPT by NPT submatrix of
! H, this factorization being ZMAT times Diag(DZ) times ZMAT^T, where
! the elements of DZ are plus or minus one, as specified by IDZ.
! NDIM is the first dimension of BMAT and has the value NPT+N.
! D is reserved for trial steps from XOPT.
! VLAG will contain the values of the Lagrange functions at a new point X.
! They are part of a product that requires VLAG to be of length NDIM.
! The array W will be used for working space. Its length must be at least
! 10*NDIM = 10*(NPT+N).
! Set some constants.
HALF=0.5D0
ONE=1.0D0
TENTH=0.1D0
ZERO=0.0D0
NP=N+1
NH=(N*NP)/2
NPTM=NPT-NP
NFTEST=MAX0(MAXFUN,1)
! Set the initial elements of XPT, BMAT, HQ, PQ and ZMAT to zero.
DO 20 J=1,N
XBASE(J)=X(J)
DO 10 K=1,NPT
10 XPT(K,J)=ZERO
DO 20 I=1,NDIM
20 BMAT(I,J)=ZERO
DO 30 IH=1,NH
30 HQ(IH)=ZERO
DO 40 K=1,NPT
PQ(K)=ZERO
DO 40 J=1,NPTM
40 ZMAT(K,J)=ZERO
! Begin the initialization procedure. NF becomes one more than the number
! of function values so far. The coordinates of the displacement of the
! next initial interpolation point from XBASE are set in XPT(NF,.).
RHOSQ=RHOBEG*RHOBEG
RECIP=ONE/RHOSQ
RECIQ=DSQRT(HALF)/RHOSQ
NF=0
50 NFM=NF
NFMM=NF-N
NF=NF+1
IF (NFM .LE. 2*N) THEN
IF (NFM .GE. 1 .AND. NFM .LE. N) THEN
XPT(NF,NFM)=RHOBEG
ELSE IF (NFM .GT. N) THEN
XPT(NF,NFMM)=-RHOBEG
END IF
ELSE
ITEMP=(NFMM-1)/N
JPT=NFM-ITEMP*N-N
IPT=JPT+ITEMP
IF (IPT .GT. N) THEN
ITEMP=JPT
JPT=IPT-N
IPT=ITEMP
END IF
XIPT=RHOBEG
IF (FVAL(IPT+NP) .LT. FVAL(IPT+1)) XIPT=-XIPT
XJPT=RHOBEG
IF (FVAL(JPT+NP) .LT. FVAL(JPT+1)) XJPT=-XJPT
XPT(NF,IPT)=XIPT
XPT(NF,JPT)=XJPT
END IF
! Calculate the next value of F, label 70 being reached immediately
! after this calculation. The least function value so far and its index
! are required.
DO 60 J=1,N
60 X(J)=XPT(NF,J)+XBASE(J)
GOTO 310
70 FVAL(NF)=F
IF (NF .EQ. 1) THEN
FBEG=F
FOPT=F
KOPT=1
ELSE IF (F .LT. FOPT) THEN
FOPT=F
KOPT=NF
END IF
! Set the nonzero initial elements of BMAT and the quadratic model in
! the cases when NF is at most 2*N+1.
IF (NFM .LE. 2*N) THEN
IF (NFM .GE. 1 .AND. NFM .LE. N) THEN
GQ(NFM)=(F-FBEG)/RHOBEG
IF (NPT .LT. NF+N) THEN
BMAT(1,NFM)=-ONE/RHOBEG
BMAT(NF,NFM)=ONE/RHOBEG
BMAT(NPT+NFM,NFM)=-HALF*RHOSQ
END IF
ELSE IF (NFM .GT. N) THEN
BMAT(NF-N,NFMM)=HALF/RHOBEG
BMAT(NF,NFMM)=-HALF/RHOBEG
ZMAT(1,NFMM)=-RECIQ-RECIQ
ZMAT(NF-N,NFMM)=RECIQ
ZMAT(NF,NFMM)=RECIQ
IH=(NFMM*(NFMM+1))/2
TEMP=(FBEG-F)/RHOBEG
HQ(IH)=(GQ(NFMM)-TEMP)/RHOBEG
GQ(NFMM)=HALF*(GQ(NFMM)+TEMP)
END IF
! Set the off-diagonal second derivatives of the Lagrange functions and
! the initial quadratic model.
ELSE
IH=(IPT*(IPT-1))/2+JPT
IF (XIPT .LT. ZERO) IPT=IPT+N
IF (XJPT .LT. ZERO) JPT=JPT+N
ZMAT(1,NFMM)=RECIP
ZMAT(NF,NFMM)=RECIP
ZMAT(IPT+1,NFMM)=-RECIP
ZMAT(JPT+1,NFMM)=-RECIP
HQ(IH)=(FBEG-FVAL(IPT+1)-FVAL(JPT+1)+F)/(XIPT*XJPT)
END IF
IF (NF .LT. NPT) GOTO 50
! Begin the iterative procedure, because the initial model is complete.
RHO=RHOBEG
DELTA=RHO
IDZ=1
DIFFA=ZERO
DIFFB=ZERO
ITEST=0
XOPTSQ=ZERO
DO 80 I=1,N
XOPT(I)=XPT(KOPT,I)
80 XOPTSQ=XOPTSQ+XOPT(I)**2
90 NFSAV=NF
! Generate the next trust region step and test its length. Set KNEW
! to -1 if the purpose of the next F will be to improve the model.
100 KNEW=0
CALL TRSAPP (N,NPT,XOPT,XPT,GQ,HQ,PQ,DELTA,D,W,W(NP), &
W(NP+N),W(NP+2*N),CRVMIN)
DSQ=ZERO
DO 110 I=1,N
110 DSQ=DSQ+D(I)**2
DNORM=DMIN1(DELTA,DSQRT(DSQ))
IF (DNORM .LT. HALF*RHO) THEN
KNEW=-1
DELTA=TENTH*DELTA
RATIO=-1.0D0
IF (DELTA .LE. 1.5D0*RHO) DELTA=RHO
IF (NF .LE. NFSAV+2) GOTO 460
TEMP=0.125D0*CRVMIN*RHO*RHO
IF (TEMP .LE. DMAX1(DIFFA,DIFFB,DIFFC)) GOTO 460
GOTO 490
END IF
! Shift XBASE if XOPT may be too far from XBASE. First make the changes
! to BMAT that do not depend on ZMAT.
120 IF (DSQ .LE. 1.0D-3*XOPTSQ) THEN
TEMPQ=0.25D0*XOPTSQ
DO 140 K=1,NPT
SUM=ZERO
DO 130 I=1,N
130 SUM=SUM+XPT(K,I)*XOPT(I)
TEMP=PQ(K)*SUM
SUM=SUM-HALF*XOPTSQ
W(NPT+K)=SUM
DO 140 I=1,N
GQ(I)=GQ(I)+TEMP*XPT(K,I)
XPT(K,I)=XPT(K,I)-HALF*XOPT(I)
VLAG(I)=BMAT(K,I)
W(I)=SUM*XPT(K,I)+TEMPQ*XOPT(I)
IP=NPT+I
DO 140 J=1,I
140 BMAT(IP,J)=BMAT(IP,J)+VLAG(I)*W(J)+W(I)*VLAG(J)
! Then the revisions of BMAT that depend on ZMAT are calculated.
DO 180 K=1,NPTM
SUMZ=ZERO
DO 150 I=1,NPT
SUMZ=SUMZ+ZMAT(I,K)
150 W(I)=W(NPT+I)*ZMAT(I,K)
DO 170 J=1,N
SUM=TEMPQ*SUMZ*XOPT(J)
DO 160 I=1,NPT
160 SUM=SUM+W(I)*XPT(I,J)
VLAG(J)=SUM
IF (K .LT. IDZ) SUM=-SUM
DO 170 I=1,NPT
170 BMAT(I,J)=BMAT(I,J)+SUM*ZMAT(I,K)
DO 180 I=1,N
IP=I+NPT
TEMP=VLAG(I)
IF (K .LT. IDZ) TEMP=-TEMP
DO 180 J=1,I
180 BMAT(IP,J)=BMAT(IP,J)+TEMP*VLAG(J)
! The following instructions complete the shift of XBASE, including
! the changes to the parameters of the quadratic model.
IH=0
DO 200 J=1,N
W(J)=ZERO
DO 190 K=1,NPT
W(J)=W(J)+PQ(K)*XPT(K,J)
190 XPT(K,J)=XPT(K,J)-HALF*XOPT(J)
DO 200 I=1,J
IH=IH+1
IF (I .LT. J) GQ(J)=GQ(J)+HQ(IH)*XOPT(I)
GQ(I)=GQ(I)+HQ(IH)*XOPT(J)
HQ(IH)=HQ(IH)+W(I)*XOPT(J)+XOPT(I)*W(J)
200 BMAT(NPT+I,J)=BMAT(NPT+J,I)
DO 210 J=1,N
XBASE(J)=XBASE(J)+XOPT(J)
210 XOPT(J)=ZERO
XOPTSQ=ZERO
END IF
! Pick the model step if KNEW is positive. A different choice of D
! may be made later, if the choice of D by BIGLAG causes substantial
! cancellation in DENOM.
IF (KNEW .GT. 0) THEN
CALL BIGLAG (N,NPT,XOPT,XPT,BMAT,ZMAT,IDZ,NDIM,KNEW,DSTEP, &
D,ALPHA,VLAG,VLAG(NPT+1),W,W(NP),W(NP+N))
END IF
! Calculate VLAG and BETA for the current choice of D. The first NPT
! components of W_check will be held in W.
DO 230 K=1,NPT
SUMA=ZERO
SUMB=ZERO
SUM=ZERO
DO 220 J=1,N
SUMA=SUMA+XPT(K,J)*D(J)
SUMB=SUMB+XPT(K,J)*XOPT(J)
220 SUM=SUM+BMAT(K,J)*D(J)
W(K)=SUMA*(HALF*SUMA+SUMB)
230 VLAG(K)=SUM
BETA=ZERO
DO 250 K=1,NPTM
SUM=ZERO
DO 240 I=1,NPT
240 SUM=SUM+ZMAT(I,K)*W(I)
IF (K .LT. IDZ) THEN
BETA=BETA+SUM*SUM
SUM=-SUM
ELSE
BETA=BETA-SUM*SUM
END IF
DO 250 I=1,NPT
250 VLAG(I)=VLAG(I)+SUM*ZMAT(I,K)
BSUM=ZERO
DX=ZERO
DO 280 J=1,N
SUM=ZERO
DO 260 I=1,NPT
260 SUM=SUM+W(I)*BMAT(I,J)
BSUM=BSUM+SUM*D(J)
JP=NPT+J
DO 270 K=1,N
270 SUM=SUM+BMAT(JP,K)*D(K)
VLAG(JP)=SUM
BSUM=BSUM+SUM*D(J)
280 DX=DX+D(J)*XOPT(J)
BETA=DX*DX+DSQ*(XOPTSQ+DX+DX+HALF*DSQ)+BETA-BSUM
VLAG(KOPT)=VLAG(KOPT)+ONE
! If KNEW is positive and if the cancellation in DENOM is unacceptable,
! then BIGDEN calculates an alternative model step, XNEW being used for
! working space.
IF (KNEW .GT. 0) THEN
TEMP=ONE+ALPHA*BETA/VLAG(KNEW)**2
IF (DABS(TEMP) .LE. 0.8D0) THEN
CALL BIGDEN (N,NPT,XOPT,XPT,BMAT,ZMAT,IDZ,NDIM,KOPT, &
KNEW,D,W,VLAG,BETA,XNEW,W(NDIM+1),W(6*NDIM+1))
END IF
END IF
! Calculate the next value of the objective function.
290 DO 300 I=1,N
XNEW(I)=XOPT(I)+D(I)
300 X(I)=XBASE(I)+XNEW(I)
NF=NF+1
310 IF (NF .GT. NFTEST) THEN
NF=NF-1
IF (IPRINT .GT. 0) PRINT 320
320 FORMAT (/4X,'Return from NEWUOA because CALFUN has been', &
' called MAXFUN times.')
GOTO 530
END IF
CALL CALFUN(X,F)
IF (IPRINT .EQ. 3) THEN
PRINT 330, NF,F,(X(I),I=1,N)
330 FORMAT (/4X,'Function number',I6,' F =',1PD18.10, &
' The corresponding X array is:'/(2X,5D15.6))
END IF
IF (NF .LE. NPT) GOTO 70
IF (KNEW .EQ. -1) GOTO 530
! Use the quadratic model to predict the change in F due to the step D,
! and set DIFF to the error of this prediction.
VQUAD=ZERO
IH=0
DO 340 J=1,N
VQUAD=VQUAD+D(J)*GQ(J)
DO 340 I=1,J
IH=IH+1
TEMP=D(I)*XNEW(J)+D(J)*XOPT(I)
IF (I .EQ. J) TEMP=HALF*TEMP
340 VQUAD=VQUAD+TEMP*HQ(IH)
DO 350 K=1,NPT
350 VQUAD=VQUAD+PQ(K)*W(K)
DIFF=F-FOPT-VQUAD
DIFFC=DIFFB
DIFFB=DIFFA
DIFFA=DABS(DIFF)
IF (DNORM .GT. RHO) NFSAV=NF
! Update FOPT and XOPT if the new F is the least value of the objective
! function so far. The branch when KNEW is positive occurs if D is not
! a trust region step.
FSAVE=FOPT
IF (F .LT. FOPT) THEN
FOPT=F
XOPTSQ=ZERO
DO 360 I=1,N
XOPT(I)=XNEW(I)
360 XOPTSQ=XOPTSQ+XOPT(I)**2
END IF
KSAVE=KNEW
IF (KNEW .GT. 0) GOTO 410
! Pick the next value of DELTA after a trust region step.
IF (VQUAD .GE. ZERO) THEN
IF (IPRINT .GT. 0) PRINT 370
370 FORMAT (/4X,'Return from NEWUOA because a trust', &
' region step has failed to reduce Q.')
GOTO 530
END IF
RATIO=(F-FSAVE)/VQUAD
IF (RATIO .LE. TENTH) THEN
DELTA=HALF*DNORM
ELSE IF (RATIO .LE. 0.7D0) THEN
DELTA=DMAX1(HALF*DELTA,DNORM)
ELSE
DELTA=DMAX1(HALF*DELTA,DNORM+DNORM)
END IF
IF (DELTA .LE. 1.5D0*RHO) DELTA=RHO
! Set KNEW to the index of the next interpolation point to be deleted.
RHOSQ=DMAX1(TENTH*DELTA,RHO)**2
KTEMP=0
DETRAT=ZERO
IF (F .GE. FSAVE) THEN
KTEMP=KOPT
DETRAT=ONE
END IF
DO 400 K=1,NPT
HDIAG=ZERO
DO 380 J=1,NPTM
TEMP=ONE
IF (J .LT. IDZ) TEMP=-ONE
380 HDIAG=HDIAG+TEMP*ZMAT(K,J)**2
TEMP=DABS(BETA*HDIAG+VLAG(K)**2)
DISTSQ=ZERO
DO 390 J=1,N
390 DISTSQ=DISTSQ+(XPT(K,J)-XOPT(J))**2
IF (DISTSQ .GT. RHOSQ) TEMP=TEMP*(DISTSQ/RHOSQ)**3
IF (TEMP .GT. DETRAT .AND. K .NE. KTEMP) THEN
DETRAT=TEMP
KNEW=K
END IF
400 CONTINUE
IF (KNEW .EQ. 0) GOTO 460
! Update BMAT, ZMAT and IDZ, so that the KNEW-th interpolation point
! can be moved. Begin the updating of the quadratic model, starting
! with the explicit second derivative term.
410 CALL UPDATE (N,NPT,BMAT,ZMAT,IDZ,NDIM,VLAG,BETA,KNEW,W)
FVAL(KNEW)=F
IH=0
DO 420 I=1,N
TEMP=PQ(KNEW)*XPT(KNEW,I)
DO 420 J=1,I
IH=IH+1
420 HQ(IH)=HQ(IH)+TEMP*XPT(KNEW,J)
PQ(KNEW)=ZERO
! Update the other second derivative parameters, and then the gradient
! vector of the model. Also include the new interpolation point.
DO 440 J=1,NPTM
TEMP=DIFF*ZMAT(KNEW,J)
IF (J .LT. IDZ) TEMP=-TEMP
DO 440 K=1,NPT
440 PQ(K)=PQ(K)+TEMP*ZMAT(K,J)
GQSQ=ZERO
DO 450 I=1,N
GQ(I)=GQ(I)+DIFF*BMAT(KNEW,I)
GQSQ=GQSQ+GQ(I)**2
450 XPT(KNEW,I)=XNEW(I)
! If a trust region step makes a small change to the objective function,
! then calculate the gradient of the least Frobenius norm interpolant at
! XBASE, and store it in W, using VLAG for a vector of right hand sides.
IF (KSAVE .EQ. 0 .AND. DELTA .EQ. RHO) THEN
IF (DABS(RATIO) .GT. 1.0D-2) THEN
ITEST=0
ELSE
DO 700 K=1,NPT
700 VLAG(K)=FVAL(K)-FVAL(KOPT)
GISQ=ZERO
DO 720 I=1,N
SUM=ZERO
DO 710 K=1,NPT
710 SUM=SUM+BMAT(K,I)*VLAG(K)
GISQ=GISQ+SUM*SUM
720 W(I)=SUM
! Test whether to replace the new quadratic model by the least Frobenius
! norm interpolant, making the replacement if the test is satisfied.
ITEST=ITEST+1
IF (GQSQ .LT. 1.0D2*GISQ) ITEST=0
IF (ITEST .GE. 3) THEN
DO 730 I=1,N
730 GQ(I)=W(I)
DO 740 IH=1,NH
740 HQ(IH)=ZERO
DO 760 J=1,NPTM
W(J)=ZERO
DO 750 K=1,NPT
750 W(J)=W(J)+VLAG(K)*ZMAT(K,J)
760 IF (J .LT. IDZ) W(J)=-W(J)
DO 770 K=1,NPT
PQ(K)=ZERO
DO 770 J=1,NPTM
770 PQ(K)=PQ(K)+ZMAT(K,J)*W(J)
ITEST=0
END IF
END IF
END IF
IF (F .LT. FSAVE) KOPT=KNEW
! If a trust region step has provided a sufficient decrease in F, then
! branch for another trust region calculation. The case KSAVE>0 occurs
! when the new function value was calculated by a model step.
IF (F .LE. FSAVE+TENTH*VQUAD) GOTO 100
IF (KSAVE .GT. 0) GOTO 100
! Alternatively, find out if the interpolation points are close enough
! to the best point so far.
KNEW=0
460 DISTSQ=4.0D0*DELTA*DELTA
DO 480 K=1,NPT
SUM=ZERO
DO 470 J=1,N
470 SUM=SUM+(XPT(K,J)-XOPT(J))**2
IF (SUM .GT. DISTSQ) THEN
KNEW=K
DISTSQ=SUM
END IF
480 CONTINUE
! If KNEW is positive, then set DSTEP, and branch back for the next
! iteration, which will generate a "model step".
IF (KNEW .GT. 0) THEN
DSTEP=DMAX1(DMIN1(TENTH*DSQRT(DISTSQ),HALF*DELTA),RHO)
DSQ=DSTEP*DSTEP
GOTO 120
END IF
IF (RATIO .GT. ZERO) GOTO 100
IF (DMAX1(DELTA,DNORM) .GT. RHO) GOTO 100
! The calculations with the current value of RHO are complete. Pick the
! next values of RHO and DELTA.
490 IF (RHO .GT. RHOEND) THEN
DELTA=HALF*RHO
RATIO=RHO/RHOEND
IF (RATIO .LE. 16.0D0) THEN
RHO=RHOEND
ELSE IF (RATIO .LE. 250.0D0) THEN
RHO=DSQRT(RATIO)*RHOEND
ELSE
RHO=TENTH*RHO
END IF
DELTA=DMAX1(DELTA,RHO)
IF (IPRINT .GE. 2) THEN
IF (IPRINT .GE. 3) PRINT 500
500 FORMAT (5X)
PRINT 510, RHO,NF
510 FORMAT (/4X,'New RHO =',1PD11.4,5X,'Current number of', &
' function evaluations =',I6)
PRINT 520, FOPT,(XBASE(I)+XOPT(I),I=1,N)
520 FORMAT (4X,'Least value of F =',1PD23.15,9X,/,4X, &
'The corresponding X array is:'/(2X,5D15.6))
END IF
GOTO 90
END IF
! Return from the calculation, after another Newton-Raphson step, if
! it is too short to have been tried before.
IF (KNEW .EQ. -1) GOTO 290
530 IF (FOPT .LE. F) THEN
DO 540 I=1,N
540 X(I)=XBASE(I)+XOPT(I)
F=FOPT
END IF
IF (IPRINT .GE. 1) THEN
PRINT 550, NF
550 FORMAT (/4X,'At the return from NEWUOA',5X, &
'Total times of function evaluations =',I6)
PRINT 520, F,(X(I),I=1,N)
END IF
RETURN
END SUBROUTINE NEWUOB
SUBROUTINE BIGDEN (N,NPT,XOPT,XPT,BMAT,ZMAT,IDZ,NDIM,KOPT, &
KNEW,D,W,VLAG,BETA,S,WVEC,PROD)
IMPLICIT REAL(8) (A-H,O-Z)
DIMENSION XOPT(*),XPT(NPT,*),BMAT(NDIM,*),ZMAT(NPT,*),D(*), &
W(*),VLAG(*),S(*),WVEC(NDIM,*),PROD(NDIM,*)
DIMENSION DEN(9),DENEX(9),PAR(9)
! N is the number of variables.
! NPT is the number of interpolation equations.
! XOPT is the best interpolation point so far.
! XPT contains the coordinates of the current interpolation points.
! BMAT provides the last N columns of H.
! ZMAT and IDZ give a factorization of the first NPT by NPT submatrix of H.
! NDIM is the first dimension of BMAT and has the value NPT+N.
! KOPT is the index of the optimal interpolation point.
! KNEW is the index of the interpolation point that is going to be moved.
! D will be set to the step from XOPT to the new point, and on entry it
! should be the D that was calculated by the last call of BIGLAG. The
! length of the initial D provides a trust region bound on the final D.
! W will be set to Wcheck for the final choice of D.
! VLAG will be set to Theta*Wcheck+e_b for the final choice of D.
! BETA will be set to the value that will occur in the updating formula
! when the KNEW-th interpolation point is moved to its new position.
! S, WVEC, PROD and the private arrays DEN, DENEX and PAR will be used
! for working space.
! D is calculated in a way that should provide a denominator with a large
! modulus in the updating formula when the KNEW-th interpolation point is
! shifted to the new position XOPT+D.
! Set some constants.
HALF=0.5D0
ONE=1.0D0
QUART=0.25D0
TWO=2.0D0
ZERO=0.0D0
TWOPI=8.0D0*DATAN(ONE)
NPTM=NPT-N-1
! Store the first NPT elements of the KNEW-th column of H in W(N+1)
! to W(N+NPT).
DO 10 K=1,NPT
10 W(N+K)=ZERO
DO 20 J=1,NPTM
TEMP=ZMAT(KNEW,J)
IF (J .LT. IDZ) TEMP=-TEMP
DO 20 K=1,NPT
20 W(N+K)=W(N+K)+TEMP*ZMAT(K,J)
ALPHA=W(N+KNEW)
! The initial search direction D is taken from the last call of BIGLAG,
! and the initial S is set below, usually to the direction from X_OPT
! to X_KNEW, but a different direction to an interpolation point may
! be chosen, in order to prevent S from being nearly parallel to D.
DD=ZERO
DS=ZERO
SS=ZERO
XOPTSQ=ZERO
DO 30 I=1,N
DD=DD+D(I)**2
S(I)=XPT(KNEW,I)-XOPT(I)
DS=DS+D(I)*S(I)
SS=SS+S(I)**2
30 XOPTSQ=XOPTSQ+XOPT(I)**2
IF (DS*DS .GT. 0.99D0*DD*SS) THEN
KSAV=KNEW
DTEST=DS*DS/SS
DO 50 K=1,NPT
IF (K .NE. KOPT) THEN
DSTEMP=ZERO
SSTEMP=ZERO
DO 40 I=1,N
DIFF=XPT(K,I)-XOPT(I)
DSTEMP=DSTEMP+D(I)*DIFF
40 SSTEMP=SSTEMP+DIFF*DIFF
IF (DSTEMP*DSTEMP/SSTEMP .LT. DTEST) THEN
KSAV=K
DTEST=DSTEMP*DSTEMP/SSTEMP
DS=DSTEMP
SS=SSTEMP
END IF
END IF
50 CONTINUE
DO 60 I=1,N
60 S(I)=XPT(KSAV,I)-XOPT(I)
END IF
SSDEN=DD*SS-DS*DS
ITERC=0
DENSAV=ZERO
! Begin the iteration by overwriting S with a vector that has the
! required length and direction.
70 ITERC=ITERC+1
TEMP=ONE/DSQRT(SSDEN)
XOPTD=ZERO
XOPTS=ZERO
DO 80 I=1,N
S(I)=TEMP*(DD*S(I)-DS*D(I))
XOPTD=XOPTD+XOPT(I)*D(I)
80 XOPTS=XOPTS+XOPT(I)*S(I)
! Set the coefficients of the first two terms of BETA.
TEMPA=HALF*XOPTD*XOPTD
TEMPB=HALF*XOPTS*XOPTS
DEN(1)=DD*(XOPTSQ+HALF*DD)+TEMPA+TEMPB
DEN(2)=TWO*XOPTD*DD
DEN(3)=TWO*XOPTS*DD
DEN(4)=TEMPA-TEMPB
DEN(5)=XOPTD*XOPTS
DO 90 I=6,9
90 DEN(I)=ZERO
! Put the coefficients of Wcheck in WVEC.
DO 110 K=1,NPT
TEMPA=ZERO
TEMPB=ZERO
TEMPC=ZERO
DO 100 I=1,N
TEMPA=TEMPA+XPT(K,I)*D(I)
TEMPB=TEMPB+XPT(K,I)*S(I)
100 TEMPC=TEMPC+XPT(K,I)*XOPT(I)
WVEC(K,1)=QUART*(TEMPA*TEMPA+TEMPB*TEMPB)
WVEC(K,2)=TEMPA*TEMPC
WVEC(K,3)=TEMPB*TEMPC
WVEC(K,4)=QUART*(TEMPA*TEMPA-TEMPB*TEMPB)
110 WVEC(K,5)=HALF*TEMPA*TEMPB
DO 120 I=1,N
IP=I+NPT
WVEC(IP,1)=ZERO
WVEC(IP,2)=D(I)
WVEC(IP,3)=S(I)
WVEC(IP,4)=ZERO
120 WVEC(IP,5)=ZERO
! Put the coefficents of THETA*Wcheck in PROD.
DO 190 JC=1,5
NW=NPT
IF (JC .EQ. 2 .OR. JC .EQ. 3) NW=NDIM
DO 130 K=1,NPT
130 PROD(K,JC)=ZERO
DO 150 J=1,NPTM
SUM=ZERO
DO 140 K=1,NPT
140 SUM=SUM+ZMAT(K,J)*WVEC(K,JC)
IF (J .LT. IDZ) SUM=-SUM
DO 150 K=1,NPT
150 PROD(K,JC)=PROD(K,JC)+SUM*ZMAT(K,J)
IF (NW .EQ. NDIM) THEN
DO 170 K=1,NPT
SUM=ZERO
DO 160 J=1,N
160 SUM=SUM+BMAT(K,J)*WVEC(NPT+J,JC)
170 PROD(K,JC)=PROD(K,JC)+SUM
END IF
DO 190 J=1,N
SUM=ZERO
DO 180 I=1,NW
180 SUM=SUM+BMAT(I,J)*WVEC(I,JC)
190 PROD(NPT+J,JC)=SUM
! Include in DEN the part of BETA that depends on THETA.
DO 210 K=1,NDIM
SUM=ZERO
DO 200 I=1,5
PAR(I)=HALF*PROD(K,I)*WVEC(K,I)
200 SUM=SUM+PAR(I)
DEN(1)=DEN(1)-PAR(1)-SUM
TEMPA=PROD(K,1)*WVEC(K,2)+PROD(K,2)*WVEC(K,1)
TEMPB=PROD(K,2)*WVEC(K,4)+PROD(K,4)*WVEC(K,2)
TEMPC=PROD(K,3)*WVEC(K,5)+PROD(K,5)*WVEC(K,3)
DEN(2)=DEN(2)-TEMPA-HALF*(TEMPB+TEMPC)
DEN(6)=DEN(6)-HALF*(TEMPB-TEMPC)
TEMPA=PROD(K,1)*WVEC(K,3)+PROD(K,3)*WVEC(K,1)
TEMPB=PROD(K,2)*WVEC(K,5)+PROD(K,5)*WVEC(K,2)
TEMPC=PROD(K,3)*WVEC(K,4)+PROD(K,4)*WVEC(K,3)
DEN(3)=DEN(3)-TEMPA-HALF*(TEMPB-TEMPC)
DEN(7)=DEN(7)-HALF*(TEMPB+TEMPC)
TEMPA=PROD(K,1)*WVEC(K,4)+PROD(K,4)*WVEC(K,1)
DEN(4)=DEN(4)-TEMPA-PAR(2)+PAR(3)
TEMPA=PROD(K,1)*WVEC(K,5)+PROD(K,5)*WVEC(K,1)
TEMPB=PROD(K,2)*WVEC(K,3)+PROD(K,3)*WVEC(K,2)
DEN(5)=DEN(5)-TEMPA-HALF*TEMPB
DEN(8)=DEN(8)-PAR(4)+PAR(5)
TEMPA=PROD(K,4)*WVEC(K,5)+PROD(K,5)*WVEC(K,4)
210 DEN(9)=DEN(9)-HALF*TEMPA
! Extend DEN so that it holds all the coefficients of DENOM.
SUM=ZERO
DO 220 I=1,5
PAR(I)=HALF*PROD(KNEW,I)**2
220 SUM=SUM+PAR(I)
DENEX(1)=ALPHA*DEN(1)+PAR(1)+SUM
TEMPA=TWO*PROD(KNEW,1)*PROD(KNEW,2)
TEMPB=PROD(KNEW,2)*PROD(KNEW,4)
TEMPC=PROD(KNEW,3)*PROD(KNEW,5)
DENEX(2)=ALPHA*DEN(2)+TEMPA+TEMPB+TEMPC
DENEX(6)=ALPHA*DEN(6)+TEMPB-TEMPC
TEMPA=TWO*PROD(KNEW,1)*PROD(KNEW,3)
TEMPB=PROD(KNEW,2)*PROD(KNEW,5)
TEMPC=PROD(KNEW,3)*PROD(KNEW,4)
DENEX(3)=ALPHA*DEN(3)+TEMPA+TEMPB-TEMPC
DENEX(7)=ALPHA*DEN(7)+TEMPB+TEMPC
TEMPA=TWO*PROD(KNEW,1)*PROD(KNEW,4)
DENEX(4)=ALPHA*DEN(4)+TEMPA+PAR(2)-PAR(3)
TEMPA=TWO*PROD(KNEW,1)*PROD(KNEW,5)
DENEX(5)=ALPHA*DEN(5)+TEMPA+PROD(KNEW,2)*PROD(KNEW,3)
DENEX(8)=ALPHA*DEN(8)+PAR(4)-PAR(5)
DENEX(9)=ALPHA*DEN(9)+PROD(KNEW,4)*PROD(KNEW,5)
! Seek the value of the angle that maximizes the modulus of DENOM.
SUM=DENEX(1)+DENEX(2)+DENEX(4)+DENEX(6)+DENEX(8)
DENOLD=SUM
DENMAX=SUM
ISAVE=0
IU=49
TEMP=TWOPI/DFLOAT(IU+1)
PAR(1)=ONE
DO 250 I=1,IU
ANGLE=DFLOAT(I)*TEMP
PAR(2)=DCOS(ANGLE)
PAR(3)=DSIN(ANGLE)
DO 230 J=4,8,2
PAR(J)=PAR(2)*PAR(J-2)-PAR(3)*PAR(J-1)
230 PAR(J+1)=PAR(2)*PAR(J-1)+PAR(3)*PAR(J-2)
SUMOLD=SUM
SUM=ZERO
DO 240 J=1,9
240 SUM=SUM+DENEX(J)*PAR(J)
IF (DABS(SUM) .GT. DABS(DENMAX)) THEN
DENMAX=SUM
ISAVE=I
TEMPA=SUMOLD
ELSE IF (I .EQ. ISAVE+1) THEN
TEMPB=SUM
END IF
250 CONTINUE
IF (ISAVE .EQ. 0) TEMPA=SUM
IF (ISAVE .EQ. IU) TEMPB=DENOLD
STEP=ZERO
IF (TEMPA .NE. TEMPB) THEN
TEMPA=TEMPA-DENMAX
TEMPB=TEMPB-DENMAX
STEP=HALF*(TEMPA-TEMPB)/(TEMPA+TEMPB)
END IF
ANGLE=TEMP*(DFLOAT(ISAVE)+STEP)
! Calculate the new parameters of the denominator, the new VLAG vector
! and the new D. Then test for convergence.
PAR(2)=DCOS(ANGLE)
PAR(3)=DSIN(ANGLE)
DO 260 J=4,8,2
PAR(J)=PAR(2)*PAR(J-2)-PAR(3)*PAR(J-1)
260 PAR(J+1)=PAR(2)*PAR(J-1)+PAR(3)*PAR(J-2)
BETA=ZERO
DENMAX=ZERO
DO 270 J=1,9
BETA=BETA+DEN(J)*PAR(J)
270 DENMAX=DENMAX+DENEX(J)*PAR(J)
DO 280 K=1,NDIM
VLAG(K)=ZERO
DO 280 J=1,5
280 VLAG(K)=VLAG(K)+PROD(K,J)*PAR(J)
TAU=VLAG(KNEW)
DD=ZERO
TEMPA=ZERO
TEMPB=ZERO
DO 290 I=1,N
D(I)=PAR(2)*D(I)+PAR(3)*S(I)
W(I)=XOPT(I)+D(I)
DD=DD+D(I)**2
TEMPA=TEMPA+D(I)*W(I)
290 TEMPB=TEMPB+W(I)*W(I)
IF (ITERC .GE. N) GOTO 340
IF (ITERC .GT. 1) DENSAV=DMAX1(DENSAV,DENOLD)
IF (DABS(DENMAX) .LE. 1.1D0*DABS(DENSAV)) GOTO 340
DENSAV=DENMAX
! Set S to half the gradient of the denominator with respect to D.
! Then branch for the next iteration.
DO 300 I=1,N
TEMP=TEMPA*XOPT(I)+TEMPB*D(I)-VLAG(NPT+I)
300 S(I)=TAU*BMAT(KNEW,I)+ALPHA*TEMP
DO 320 K=1,NPT
SUM=ZERO
DO 310 J=1,N
310 SUM=SUM+XPT(K,J)*W(J)
TEMP=(TAU*W(N+K)-ALPHA*VLAG(K))*SUM
DO 320 I=1,N
320 S(I)=S(I)+TEMP*XPT(K,I)
SS=ZERO
DS=ZERO
DO 330 I=1,N
SS=SS+S(I)**2
330 DS=DS+D(I)*S(I)
SSDEN=DD*SS-DS*DS
IF (SSDEN .GE. 1.0D-8*DD*SS) GOTO 70
! Set the vector W before the RETURN from the subroutine.
340 DO 350 K=1,NDIM
W(K)=ZERO
DO 350 J=1,5
350 W(K)=W(K)+WVEC(K,J)*PAR(J)
VLAG(KOPT)=VLAG(KOPT)+ONE
RETURN
END SUBROUTINE BIGDEN
SUBROUTINE BIGLAG (N,NPT,XOPT,XPT,BMAT,ZMAT,IDZ,NDIM,KNEW, &
DELTA,D,ALPHA,HCOL,GC,GD,S,W)
IMPLICIT REAL(8) (A-H,O-Z)
DIMENSION XOPT(*),XPT(NPT,*),BMAT(NDIM,*),ZMAT(NPT,*),D(*), &
HCOL(*),GC(*),GD(*),S(*),W(*)
! N is the number of variables.
! NPT is the number of interpolation equations.
! XOPT is the best interpolation point so far.
! XPT contains the coordinates of the current interpolation points.
! BMAT provides the last N columns of H.
! ZMAT and IDZ give a factorization of the first NPT by NPT submatrix of H.
! NDIM is the first dimension of BMAT and has the value NPT+N.
! KNEW is the index of the interpolation point that is going to be moved.
! DELTA is the current trust region bound.
! D will be set to the step from XOPT to the new point.
! ALPHA will be set to the KNEW-th diagonal element of the H matrix.
! HCOL, GC, GD, S and W will be used for working space.
! The step D is calculated in a way that attempts to maximize the modulus
! of LFUNC(XOPT+D), subject to the bound ||D|| .LE. DELTA, where LFUNC is
! the KNEW-th Lagrange function.
! Set some constants.
HALF=0.5D0
ONE=1.0D0
ZERO=0.0D0
TWOPI=8.0D0*DATAN(ONE)
DELSQ=DELTA*DELTA
NPTM=NPT-N-1
! Set the first NPT components of HCOL to the leading elements of the
! KNEW-th column of H.
ITERC=0
DO 10 K=1,NPT
10 HCOL(K)=ZERO
DO 20 J=1,NPTM
TEMP=ZMAT(KNEW,J)
IF (J .LT. IDZ) TEMP=-TEMP
DO 20 K=1,NPT
20 HCOL(K)=HCOL(K)+TEMP*ZMAT(K,J)
ALPHA=HCOL(KNEW)
! Set the unscaled initial direction D. Form the gradient of LFUNC at
! XOPT, and multiply D by the second derivative matrix of LFUNC.
DD=ZERO
DO 30 I=1,N
D(I)=XPT(KNEW,I)-XOPT(I)
GC(I)=BMAT(KNEW,I)
GD(I)=ZERO
30 DD=DD+D(I)**2
DO 50 K=1,NPT
TEMP=ZERO
SUM=ZERO
DO 40 J=1,N
TEMP=TEMP+XPT(K,J)*XOPT(J)
40 SUM=SUM+XPT(K,J)*D(J)
TEMP=HCOL(K)*TEMP
SUM=HCOL(K)*SUM
DO 50 I=1,N
GC(I)=GC(I)+TEMP*XPT(K,I)
50 GD(I)=GD(I)+SUM*XPT(K,I)
! Scale D and GD, with a sign change if required. Set S to another
! vector in the initial two dimensional subspace.
GG=ZERO
SP=ZERO
DHD=ZERO
DO 60 I=1,N
GG=GG+GC(I)**2
SP=SP+D(I)*GC(I)
60 DHD=DHD+D(I)*GD(I)
SCALE=DELTA/DSQRT(DD)
IF (SP*DHD .LT. ZERO) SCALE=-SCALE
TEMP=ZERO
IF (SP*SP .GT. 0.99D0*DD*GG) TEMP=ONE
TAU=SCALE*(DABS(SP)+HALF*SCALE*DABS(DHD))
IF (GG*DELSQ .LT. 0.01D0*TAU*TAU) TEMP=ONE
DO 70 I=1,N
D(I)=SCALE*D(I)
GD(I)=SCALE*GD(I)
70 S(I)=GC(I)+TEMP*GD(I)
! Begin the iteration by overwriting S with a vector that has the
! required length and direction, except that termination occurs if
! the given D and S are nearly parallel.
80 ITERC=ITERC+1
DD=ZERO
SP=ZERO
SS=ZERO
DO 90 I=1,N
DD=DD+D(I)**2
SP=SP+D(I)*S(I)
90 SS=SS+S(I)**2
TEMP=DD*SS-SP*SP
IF (TEMP .LE. 1.0D-8*DD*SS) GOTO 160
DENOM=DSQRT(TEMP)
DO 100 I=1,N
S(I)=(DD*S(I)-SP*D(I))/DENOM
100 W(I)=ZERO
! Calculate the coefficients of the objective function on the circle,
! beginning with the multiplication of S by the second derivative matrix.
DO 120 K=1,NPT
SUM=ZERO
DO 110 J=1,N
110 SUM=SUM+XPT(K,J)*S(J)
SUM=HCOL(K)*SUM
DO 120 I=1,N
120 W(I)=W(I)+SUM*XPT(K,I)
CF1=ZERO
CF2=ZERO
CF3=ZERO
CF4=ZERO
CF5=ZERO
DO 130 I=1,N
CF1=CF1+S(I)*W(I)
CF2=CF2+D(I)*GC(I)
CF3=CF3+S(I)*GC(I)
CF4=CF4+D(I)*GD(I)
130 CF5=CF5+S(I)*GD(I)
CF1=HALF*CF1
CF4=HALF*CF4-CF1
! Seek the value of the angle that maximizes the modulus of TAU.
TAUBEG=CF1+CF2+CF4
TAUMAX=TAUBEG
TAUOLD=TAUBEG
ISAVE=0
IU=49
TEMP=TWOPI/DFLOAT(IU+1)
DO 140 I=1,IU
ANGLE=DFLOAT(I)*TEMP
CTH=DCOS(ANGLE)
STH=DSIN(ANGLE)
TAU=CF1+(CF2+CF4*CTH)*CTH+(CF3+CF5*CTH)*STH
IF (DABS(TAU) .GT. DABS(TAUMAX)) THEN
TAUMAX=TAU
ISAVE=I
TEMPA=TAUOLD
ELSE IF (I .EQ. ISAVE+1) THEN
TEMPB=TAU
END IF
140 TAUOLD=TAU
IF (ISAVE .EQ. 0) TEMPA=TAU
IF (ISAVE .EQ. IU) TEMPB=TAUBEG
STEP=ZERO
IF (TEMPA .NE. TEMPB) THEN
TEMPA=TEMPA-TAUMAX
TEMPB=TEMPB-TAUMAX
STEP=HALF*(TEMPA-TEMPB)/(TEMPA+TEMPB)
END IF
ANGLE=TEMP*(DFLOAT(ISAVE)+STEP)
! Calculate the new D and GD. Then test for convergence.
CTH=DCOS(ANGLE)
STH=DSIN(ANGLE)
TAU=CF1+(CF2+CF4*CTH)*CTH+(CF3+CF5*CTH)*STH
DO 150 I=1,N
D(I)=CTH*D(I)+STH*S(I)
GD(I)=CTH*GD(I)+STH*W(I)
150 S(I)=GC(I)+GD(I)
IF (DABS(TAU) .LE. 1.1D0*DABS(TAUBEG)) GOTO 160
IF (ITERC .LT. N) GOTO 80
160 RETURN
END SUBROUTINE BIGLAG
SUBROUTINE TRSAPP (N,NPT,XOPT,XPT,GQ,HQ,PQ,DELTA,STEP, &
D,G,HD,HS,CRVMIN)
IMPLICIT REAL(8) (A-H,O-Z)
DIMENSION XOPT(*),XPT(NPT,*),GQ(*),HQ(*),PQ(*),STEP(*), &
D(*),G(*),HD(*),HS(*)
! N is the number of variables of a quadratic objective function, Q say.
! The arguments NPT, XOPT, XPT, GQ, HQ and PQ have their usual meanings,
! in order to define the current quadratic model Q.
! DELTA is the trust region radius, and has to be positive.
! STEP will be set to the calculated trial step.
! The arrays D, G, HD and HS will be used for working space.
! CRVMIN will be set to the least curvature of H along the conjugate
! directions that occur, except that it is set to zero if STEP goes
! all the way to the trust region boundary.
! The calculation of STEP begins with the truncated conjugate gradient
! method. If the boundary of the trust region is reached, then further
! changes to STEP may be made, each one being in the 2D space spanned
! by the current STEP and the corresponding gradient of Q. Thus STEP
! should provide a substantial reduction to Q within the trust region.
! Initialization, which includes setting HD to H times XOPT.
HALF=0.5D0
ZERO=0.0D0
TWOPI=8.0D0*DATAN(1.0D0)
DELSQ=DELTA*DELTA
ITERC=0
ITERMAX=N
ITERSW=ITERMAX
DO 10 I=1,N
10 D(I)=XOPT(I)
GOTO 170
! Prepare for the first line search.
20 QRED=ZERO
DD=ZERO
DO 30 I=1,N
STEP(I)=ZERO
HS(I)=ZERO
G(I)=GQ(I)+HD(I)
D(I)=-G(I)
30 DD=DD+D(I)**2
CRVMIN=ZERO
IF (DD .EQ. ZERO) GOTO 160
DS=ZERO
SS=ZERO
GG=DD
GGBEG=GG
! Calculate the step to the trust region boundary and the product HD.
40 ITERC=ITERC+1
TEMP=DELSQ-SS
BSTEP=TEMP/(DS+DSQRT(DS*DS+DD*TEMP))
GOTO 170
50 DHD=ZERO
DO 60 J=1,N
60 DHD=DHD+D(J)*HD(J)
! Update CRVMIN and set the step-length ALPHA.
ALPHA=BSTEP
IF (DHD .GT. ZERO) THEN
TEMP=DHD/DD
IF (ITERC .EQ. 1) CRVMIN=TEMP
CRVMIN=DMIN1(CRVMIN,TEMP)
ALPHA=DMIN1(ALPHA,GG/DHD)
END IF
QADD=ALPHA*(GG-HALF*ALPHA*DHD)
QRED=QRED+QADD
! Update STEP and HS.
GGSAV=GG
GG=ZERO
DO 70 I=1,N
STEP(I)=STEP(I)+ALPHA*D(I)
HS(I)=HS(I)+ALPHA*HD(I)
70 GG=GG+(G(I)+HS(I))**2
! Begin another conjugate direction iteration if required.
IF (ALPHA .LT. BSTEP) THEN
IF (QADD .LE. 0.01D0*QRED) GOTO 160
IF (GG .LE. 1.0D-4*GGBEG) GOTO 160
IF (ITERC .EQ. ITERMAX) GOTO 160
TEMP=GG/GGSAV
DD=ZERO
DS=ZERO
SS=ZERO
DO 80 I=1,N
D(I)=TEMP*D(I)-G(I)-HS(I)
DD=DD+D(I)**2
DS=DS+D(I)*STEP(I)
80 SS=SS+STEP(I)**2
IF (DS .LE. ZERO) GOTO 160
IF (SS .LT. DELSQ) GOTO 40
END IF
CRVMIN=ZERO
ITERSW=ITERC
! Test whether an alternative iteration is required.
90 IF (GG .LE. 1.0D-4*GGBEG) GOTO 160
SG=ZERO
SHS=ZERO
DO 100 I=1,N
SG=SG+STEP(I)*G(I)
100 SHS=SHS+STEP(I)*HS(I)
SGK=SG+SHS
ANGTEST=SGK/DSQRT(GG*DELSQ)
IF (ANGTEST .LE. -0.99D0) GOTO 160
! Begin the alternative iteration by calculating D and HD and some
! scalar products.
ITERC=ITERC+1
TEMP=DSQRT(DELSQ*GG-SGK*SGK)
TEMPA=DELSQ/TEMP
TEMPB=SGK/TEMP
DO 110 I=1,N
110 D(I)=TEMPA*(G(I)+HS(I))-TEMPB*STEP(I)
GOTO 170
120 DG=ZERO
DHD=ZERO
DHS=ZERO
DO 130 I=1,N
DG=DG+D(I)*G(I)
DHD=DHD+HD(I)*D(I)
130 DHS=DHS+HD(I)*STEP(I)
! Seek the value of the angle that minimizes Q.
CF=HALF*(SHS-DHD)
QBEG=SG+CF
QSAV=QBEG
QMIN=QBEG
ISAVE=0
IU=49
TEMP=TWOPI/DFLOAT(IU+1)
DO 140 I=1,IU
ANGLE=DFLOAT(I)*TEMP
CTH=DCOS(ANGLE)
STH=DSIN(ANGLE)
QNEW=(SG+CF*CTH)*CTH+(DG+DHS*CTH)*STH
IF (QNEW .LT. QMIN) THEN
QMIN=QNEW
ISAVE=I
TEMPA=QSAV
ELSE IF (I .EQ. ISAVE+1) THEN
TEMPB=QNEW
END IF
140 QSAV=QNEW
IF (ISAVE .EQ. ZERO) TEMPA=QNEW
IF (ISAVE .EQ. IU) TEMPB=QBEG
ANGLE=ZERO
IF (TEMPA .NE. TEMPB) THEN
TEMPA=TEMPA-QMIN
TEMPB=TEMPB-QMIN
ANGLE=HALF*(TEMPA-TEMPB)/(TEMPA+TEMPB)
END IF
ANGLE=TEMP*(DFLOAT(ISAVE)+ANGLE)
! Calculate the new STEP and HS. Then test for convergence.
CTH=DCOS(ANGLE)
STH=DSIN(ANGLE)
REDUC=QBEG-(SG+CF*CTH)*CTH-(DG+DHS*CTH)*STH
GG=ZERO
DO 150 I=1,N
STEP(I)=CTH*STEP(I)+STH*D(I)
HS(I)=CTH*HS(I)+STH*HD(I)
150 GG=GG+(G(I)+HS(I))**2
QRED=QRED+REDUC
RATIO=REDUC/QRED
IF (ITERC .LT. ITERMAX .AND. RATIO .GT. 0.01D0) GOTO 90
160 RETURN
! The following instructions act as a subroutine for setting the vector
! HD to the vector D multiplied by the second derivative matrix of Q.
! They are called from three different places, which are distinguished
! by the value of ITERC.
170 DO 180 I=1,N
180 HD(I)=ZERO
DO 200 K=1,NPT
TEMP=ZERO
DO 190 J=1,N
190 TEMP=TEMP+XPT(K,J)*D(J)
TEMP=TEMP*PQ(K)
DO 200 I=1,N
200 HD(I)=HD(I)+TEMP*XPT(K,I)
IH=0
DO 210 J=1,N
DO 210 I=1,J
IH=IH+1
IF (I .LT. J) HD(J)=HD(J)+HQ(IH)*D(I)
210 HD(I)=HD(I)+HQ(IH)*D(J)
IF (ITERC .EQ. 0) GOTO 20
IF (ITERC .LE. ITERSW) GOTO 50
GOTO 120
END SUBROUTINE TRSAPP
SUBROUTINE UPDATE (N,NPT,BMAT,ZMAT,IDZ,NDIM,VLAG,BETA,KNEW,W)
IMPLICIT REAL(8) (A-H,O-Z)
DIMENSION BMAT(NDIM,*),ZMAT(NPT,*),VLAG(*),W(*)
! The arrays BMAT and ZMAT with IDZ are updated, in order to shift the
! interpolation point that has index KNEW. On entry, VLAG contains the
! components of the vector Theta*Wcheck+e_b of the updating formula
! (6.11), and BETA holds the value of the parameter that has this name.
! The vector W is used for working space.
! Set some constants.
ONE=1.0D0
ZERO=0.0D0
NPTM=NPT-N-1
! Apply the rotations that put zeros in the KNEW-th row of ZMAT.
JL=1
DO 20 J=2,NPTM
IF (J .EQ. IDZ) THEN
JL=IDZ
ELSE IF (ZMAT(KNEW,J) .NE. ZERO) THEN
TEMP=DSQRT(ZMAT(KNEW,JL)**2+ZMAT(KNEW,J)**2)
TEMPA=ZMAT(KNEW,JL)/TEMP
TEMPB=ZMAT(KNEW,J)/TEMP
DO 10 I=1,NPT
TEMP=TEMPA*ZMAT(I,JL)+TEMPB*ZMAT(I,J)
ZMAT(I,J)=TEMPA*ZMAT(I,J)-TEMPB*ZMAT(I,JL)
10 ZMAT(I,JL)=TEMP
ZMAT(KNEW,J)=ZERO
END IF
20 CONTINUE
! Put the first NPT components of the KNEW-th column of HLAG into W,
! and calculate the parameters of the updating formula.
TEMPA=ZMAT(KNEW,1)
IF (IDZ .GE. 2) TEMPA=-TEMPA
IF (JL .GT. 1) TEMPB=ZMAT(KNEW,JL)
DO 30 I=1,NPT
W(I)=TEMPA*ZMAT(I,1)
IF (JL .GT. 1) W(I)=W(I)+TEMPB*ZMAT(I,JL)
30 CONTINUE
ALPHA=W(KNEW)
TAU=VLAG(KNEW)
TAUSQ=TAU*TAU
DENOM=ALPHA*BETA+TAUSQ
VLAG(KNEW)=VLAG(KNEW)-ONE
! Complete the updating of ZMAT when there is only one nonzero element
! in the KNEW-th row of the new matrix ZMAT, but, if IFLAG is set to one,
! then the first column of ZMAT will be exchanged with another one later.
IFLAG=0
IF (JL .EQ. 1) THEN
TEMP=DSQRT(DABS(DENOM))
TEMPB=TEMPA/TEMP
TEMPA=TAU/TEMP
DO 40 I=1,NPT
40 ZMAT(I,1)=TEMPA*ZMAT(I,1)-TEMPB*VLAG(I)
IF (IDZ .EQ. 1 .AND. TEMP .LT. ZERO) IDZ=2
IF (IDZ .GE. 2 .AND. TEMP .GE. ZERO) IFLAG=1
ELSE
! Complete the updating of ZMAT in the alternative case.
JA=1
IF (BETA .GE. ZERO) JA=JL
JB=JL+1-JA
TEMP=ZMAT(KNEW,JB)/DENOM
TEMPA=TEMP*BETA
TEMPB=TEMP*TAU
TEMP=ZMAT(KNEW,JA)
SCALA=ONE/DSQRT(DABS(BETA)*TEMP*TEMP+TAUSQ)
SCALB=SCALA*DSQRT(DABS(DENOM))
DO 50 I=1,NPT
ZMAT(I,JA)=SCALA*(TAU*ZMAT(I,JA)-TEMP*VLAG(I))
50 ZMAT(I,JB)=SCALB*(ZMAT(I,JB)-TEMPA*W(I)-TEMPB*VLAG(I))
IF (DENOM .LE. ZERO) THEN
IF (BETA .LT. ZERO) IDZ=IDZ+1
IF (BETA .GE. ZERO) IFLAG=1
END IF
END IF
! IDZ is reduced in the following case, and usually the first column
! of ZMAT is exchanged with a later one.
IF (IFLAG .EQ. 1) THEN
IDZ=IDZ-1
DO 60 I=1,NPT
TEMP=ZMAT(I,1)
ZMAT(I,1)=ZMAT(I,IDZ)
60 ZMAT(I,IDZ)=TEMP
END IF
! Finally, update the matrix BMAT.
DO 70 J=1,N
JP=NPT+J
W(JP)=BMAT(KNEW,J)
TEMPA=(ALPHA*VLAG(JP)-TAU*W(JP))/DENOM
TEMPB=(-BETA*W(JP)-TAU*VLAG(JP))/DENOM
DO 70 I=1,JP
BMAT(I,J)=BMAT(I,J)+TEMPA*VLAG(I)+TEMPB*W(I)
IF (I .GT. NPT) BMAT(JP,I-NPT)=BMAT(I,J)
70 CONTINUE
RETURN
END SUBROUTINE UPDATE
END MODULE newuoa_module
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