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.
| Type | Intent | Optional | Attributes | Name | ||
|---|---|---|---|---|---|---|
| integer, | intent(in) | :: | n |
the number of variables. must be at least 2. |
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| integer, | intent(in) | :: | npt |
The number of interpolation conditions.
Its value must be in the interval |
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| real(kind=wp), | intent(inout), | dimension(*) | :: | x |
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. |
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| real(kind=wp), | intent(in) | :: | rhobeg |
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. |
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| real(kind=wp), | intent(in) | :: | rhoend |
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. |
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| integer, | intent(in) | :: | iprint |
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. |
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| integer, | intent(in) | :: | maxfun |
an upper bound on the number of calls of CALFUN. |
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| procedure(func) | :: | calfun |
It must set F to the value of the objective function
for the variables |
subroutine newuoa (n, npt, x, rhobeg, rhoend, iprint, maxfun, calfun) implicit none integer,intent(in) :: n !! the number of variables. must be at least 2. integer,intent(in) :: npt !! The number of interpolation conditions. !! Its value must be in the interval `[N+2,(N+1)(N+2)/2]`. real(wp),dimension(*),intent(inout) :: x !! 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. real(wp),intent(in) :: rhobeg !! 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. real(wp),intent(in) :: rhoend !! 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. integer,intent(in) :: iprint !! 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. integer,intent(in) :: maxfun !! an upper bound on the number of calls of CALFUN. procedure(func) :: calfun !! It must set F to the value of the objective function !! for the variables `X(1),X(2),...,X(N)`. real(wp),dimension(:),allocatable :: w integer :: np,nptm,ndim,ixb,ixo,ixn,ixp,ifv,igq,ihq,ipq,ibmat,izmat,id,ivl,iw ! 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 < n+2 .or. npt > ((n+2)*np)/2) then write(*,*) 'Return from NEWUOA because NPT is not in the required interval' return end if ! The array W will be used for working space allocate(w((NPT+13)*(NPT+N)+3*N*(N+3)/2)) 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 (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), calfun) deallocate(w) end subroutine newuoa