You cannot select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
384 lines
12 KiB
Fortran
384 lines
12 KiB
Fortran
! File: psb_dbgmres.f90
|
|
!
|
|
! Subroutine: psb_dbgmres
|
|
! This subroutine implements the BGMRES method with right preconditioning.
|
|
!
|
|
! Arguments:
|
|
!
|
|
! a - type(psb_dspmat_type) Input: sparse matrix containing A.
|
|
! prec - class(psb_dprec_type) Input: preconditioner
|
|
! b - real,dimension(:,:) Input: vector containing the
|
|
! right hand side B
|
|
! x - real,dimension(:,:) Input/Output: vector containing the
|
|
! initial guess and final solution X.
|
|
! eps - real Input: Stopping tolerance; the iteration is
|
|
! stopped when the error estimate |err| <= eps
|
|
! desc_a - type(psb_desc_type). Input: The communication descriptor.
|
|
! info - integer. Output: Return code
|
|
!
|
|
! itmax - integer(optional) Input: maximum number of iterations to be
|
|
! performed.
|
|
!
|
|
! iter - integer(optional) Output: how many iterations have been
|
|
! performed.
|
|
! performed.
|
|
! err - real (optional) Output: error estimate on exit. If the
|
|
! denominator of the estimate is exactly
|
|
! 0, it is changed into 1.
|
|
! itrace - integer(optional) Input: print an informational message
|
|
! with the error estimate every itrace
|
|
! iterations
|
|
! itrs - integer(optional) Input: iteration number parameter
|
|
! istop - integer(optional) Input: stopping criterion, or how
|
|
! to estimate the error.
|
|
! 1: err = |r|/(|a||x|+|b|); here the iteration is
|
|
! stopped when |r| <= eps * (|a||x|+|b|)
|
|
! 2: err = |r|/|b|; here the iteration is
|
|
! stopped when |r| <= eps * |b|
|
|
! where r is the (preconditioned, recursive
|
|
! estimate of) residual.
|
|
!
|
|
|
|
subroutine psb_dbgmres_multivect(a, prec, b, x, eps, desc_a, info, itmax, iter, err, itrace, itrs, istop)
|
|
|
|
use psb_base_mod
|
|
use psb_prec_mod
|
|
use psb_d_krylov_conv_mod
|
|
use psb_krylov_mod
|
|
|
|
implicit none
|
|
|
|
type(psb_dspmat_type), intent(in) :: a
|
|
type(psb_desc_type), Intent(in) :: desc_a
|
|
class(psb_dprec_type), intent(inout) :: prec
|
|
|
|
type(psb_d_multivect_type), Intent(inout) :: b
|
|
type(psb_d_multivect_type), Intent(inout) :: x
|
|
|
|
real(psb_dpk_), Intent(in) :: eps
|
|
integer(psb_ipk_), intent(out) :: info
|
|
integer(psb_ipk_), Optional, Intent(in) :: itmax, itrace, itrs, istop
|
|
integer(psb_ipk_), Optional, Intent(out) :: iter
|
|
real(psb_dpk_), Optional, Intent(out) :: err
|
|
|
|
real(psb_dpk_), allocatable :: aux(:), h(:,:), beta(:,:)
|
|
|
|
type(psb_d_multivect_type), allocatable :: v(:)
|
|
type(psb_d_multivect_type) :: v_tot, w
|
|
|
|
real(psb_dpk_) :: t1, t2
|
|
|
|
real(psb_dpk_) :: rti, rti1
|
|
integer(psb_ipk_) :: litmax, naux, itrace_, n_row, n_col, nrep
|
|
integer(psb_lpk_) :: mglob, m, n, n_add
|
|
integer(psb_ipk_) :: n_
|
|
|
|
integer(psb_ipk_) :: i, j, istop_, err_act, idx_i, idx_j, idx
|
|
integer(psb_ipk_) :: debug_level, debug_unit
|
|
|
|
type(psb_ctxt_type) :: ctxt
|
|
integer(psb_ipk_) :: np, me, itx
|
|
real(psb_dpk_) :: rni, xni, bni, ani, bn2, r0n2
|
|
real(psb_dpk_) :: errnum, errden, deps, derr
|
|
character(len=20) :: name
|
|
character(len=*), parameter :: methdname='BGMRES'
|
|
|
|
info = psb_success_
|
|
name = 'psb_dbgmres'
|
|
call psb_erractionsave(err_act)
|
|
debug_unit = psb_get_debug_unit()
|
|
debug_level = psb_get_debug_level()
|
|
|
|
ctxt = desc_a%get_context()
|
|
call psb_info(ctxt, me, np)
|
|
|
|
if (debug_level >= psb_debug_ext_) &
|
|
& write(debug_unit,*) me,' ',trim(name),': from psb_info',np
|
|
|
|
if (.not.allocated(b%v)) then
|
|
info = psb_err_invalid_vect_state_
|
|
call psb_errpush(info,name)
|
|
goto 9999
|
|
endif
|
|
if (.not.allocated(x%v)) then
|
|
info = psb_err_invalid_vect_state_
|
|
call psb_errpush(info,name)
|
|
goto 9999
|
|
endif
|
|
|
|
mglob = desc_a%get_global_rows()
|
|
n_row = desc_a%get_local_rows()
|
|
n_col = desc_a%get_local_cols()
|
|
|
|
if (present(istop)) then
|
|
istop_ = istop
|
|
else
|
|
istop_ = 2
|
|
endif
|
|
|
|
if ((istop_ < 1 ).or.(istop_ > 2 ) ) then
|
|
info=psb_err_invalid_istop_
|
|
err=info
|
|
call psb_errpush(info,name,i_err=(/istop_/))
|
|
goto 9999
|
|
endif
|
|
|
|
if (present(itmax)) then
|
|
litmax = itmax
|
|
else
|
|
litmax = 1000
|
|
endif
|
|
|
|
if (present(itrace)) then
|
|
itrace_ = itrace
|
|
else
|
|
itrace_ = 0
|
|
end if
|
|
|
|
if (present(itrs)) then
|
|
nrep = itrs
|
|
if (debug_level >= psb_debug_ext_) &
|
|
& write(debug_unit,*) me,' ',trim(name),&
|
|
& ' present: itrs: ',itrs,nrep
|
|
else
|
|
nrep = 10
|
|
if (debug_level >= psb_debug_ext_) &
|
|
& write(debug_unit,*) me,' ',trim(name),&
|
|
& ' not present: itrs: ',itrs,nrep
|
|
endif
|
|
if (nrep <=0 ) then
|
|
info=psb_err_invalid_irst_
|
|
err=info
|
|
call psb_errpush(info,name,i_err=(/nrep/))
|
|
goto 9999
|
|
endif
|
|
|
|
m = x%get_nrows()
|
|
n = x%get_ncols()
|
|
|
|
call psb_chkvect(m,n,x%get_nrows(),lone,lone,desc_a,info)
|
|
if(info /= psb_success_) then
|
|
info=psb_err_from_subroutine_
|
|
call psb_errpush(info,name,a_err='psb_chkvect on X')
|
|
goto 9999
|
|
end if
|
|
call psb_chkvect(m,n,b%get_nrows(),lone,lone,desc_a,info)
|
|
if(info /= psb_success_) then
|
|
info=psb_err_from_subroutine_
|
|
call psb_errpush(info,name,a_err='psb_chkvect on B')
|
|
goto 9999
|
|
end if
|
|
|
|
naux=4*n_col
|
|
allocate(aux(naux),h((nrep+1)*n,nrep*n),stat=info)
|
|
|
|
n_ = n
|
|
if (info == psb_success_) call psb_geall(v,desc_a,info,m=nrep+1,n=n_)
|
|
if (info == psb_success_) call psb_geall(v_tot,desc_a,info,n=(nrep+1)*n_)
|
|
if (info == psb_success_) call psb_geall(w,desc_a,info,n=n_)
|
|
if (info == psb_success_) call psb_geasb(v,desc_a,info,mold=x%v,n=n_)
|
|
if (info == psb_success_) call psb_geasb(v_tot,desc_a,info,mold=x%v,n=(nrep+1)*n_)
|
|
if (info == psb_success_) call psb_geasb(w,desc_a,info,mold=x%v,n=n_)
|
|
if (info /= psb_success_) then
|
|
info=psb_err_from_subroutine_non_
|
|
call psb_errpush(info,name)
|
|
goto 9999
|
|
end if
|
|
|
|
if (debug_level >= psb_debug_ext_) &
|
|
& write(debug_unit,*) me,' ',trim(name),&
|
|
& ' Size of V,W ',v(1)%get_nrows(),size(v),&
|
|
& w%get_nrows()
|
|
|
|
if (istop_ == 1) then
|
|
ani = psb_spnrmi(a,desc_a,info)
|
|
bni = psb_geamax(b,desc_a,info)
|
|
else if (istop_ == 2) then
|
|
bn2 = psb_genrm2(b,desc_a,info)
|
|
endif
|
|
if (info /= psb_success_) then
|
|
info=psb_err_from_subroutine_non_
|
|
call psb_errpush(info,name)
|
|
goto 9999
|
|
end if
|
|
|
|
errnum = dzero
|
|
errden = done
|
|
deps = eps
|
|
itx = 0
|
|
n_add = n-1
|
|
|
|
if ((itrace_ > 0).and.(me == psb_root_)) call log_header(methdname)
|
|
|
|
! BGMRES algorithm
|
|
|
|
! TODO inserire timer operazioni tra mlv
|
|
|
|
! STEP 1: Compute R(0) = B - A*X(0)
|
|
|
|
! Store B in V(1)
|
|
call psb_geaxpby(done,b,dzero,v(1),desc_a,info)
|
|
if (info /= psb_success_) then
|
|
info=psb_err_from_subroutine_non_
|
|
call psb_errpush(info,name)
|
|
goto 9999
|
|
end if
|
|
|
|
! Store R(0) in V(1)
|
|
call psb_spmm(-done,a,x,done,v(1),desc_a,info,work=aux)
|
|
if (info /= psb_success_) then
|
|
info=psb_err_from_subroutine_non_
|
|
call psb_errpush(info,name)
|
|
goto 9999
|
|
end if
|
|
|
|
! STEP 2: Compute QR_fact(R(0))
|
|
beta = psb_geqrfact(v(1),desc_a,info)
|
|
if (info /= psb_success_) then
|
|
info=psb_err_from_subroutine_non_
|
|
call psb_errpush(info,name)
|
|
goto 9999
|
|
end if
|
|
|
|
! STEP 3: Outer loop
|
|
outer: do j=1,nrep
|
|
|
|
itx = itx + 1
|
|
|
|
! Compute j index for H operations
|
|
idx_j = (j-1)*n+1
|
|
|
|
! STEP 4: Compute W = AV(j)
|
|
call psb_spmm(done,a,v(j),dzero,w,desc_a,info,work=aux)
|
|
if (info /= psb_success_) then
|
|
info=psb_err_from_subroutine_non_
|
|
call psb_errpush(info,name)
|
|
goto 9999
|
|
end if
|
|
|
|
if (itx >= litmax) exit outer
|
|
|
|
! STEP 5: Inner loop
|
|
inner: do i=1,j
|
|
|
|
! Compute i index for H operations
|
|
idx_i = (i-1)*n+1
|
|
|
|
! STEP 6: Compute H(i,j) = V(i)_T*W
|
|
h(idx_i:idx_i+n_add,idx_j:idx_j+n_add) = psb_gedot(v(i),w,desc_a,info,.true.)
|
|
if (info /= psb_success_) then
|
|
info=psb_err_from_subroutine_non_
|
|
call psb_errpush(info,name)
|
|
goto 9999
|
|
end if
|
|
|
|
! STEP 7: Compute W = W - V(i)*H(i,j)
|
|
call psb_geaxpby(-done,psb_gedot(v(i),h(idx_i:idx_i+n_add,idx_j:idx_j+n_add),desc_a,info),done,w,desc_a,info)
|
|
if (info /= psb_success_) then
|
|
info=psb_err_from_subroutine_non_
|
|
call psb_errpush(info,name)
|
|
goto 9999
|
|
end if
|
|
|
|
end do inner
|
|
|
|
! STEP 8: Compute QR_fact(W)
|
|
|
|
! Store R in H(j+1,j)
|
|
h(idx_j+n:idx_j+n+n_add,idx_j:idx_j+n_add) = psb_geqrfact(w,desc_a,info)
|
|
if (info /= psb_success_) then
|
|
info=psb_err_from_subroutine_non_
|
|
call psb_errpush(info,name)
|
|
goto 9999
|
|
end if
|
|
|
|
! Store Q in V(j+1)
|
|
call psb_geaxpby(done,w,dzero,v(j+1),desc_a,info)
|
|
if (info /= psb_success_) then
|
|
info=psb_err_from_subroutine_non_
|
|
call psb_errpush(info,name)
|
|
goto 9999
|
|
end if
|
|
|
|
end do outer
|
|
|
|
! STEP 9: Compute Y(m)
|
|
call frobenius_norm_min()
|
|
if (info /= psb_success_) then
|
|
info=psb_err_from_subroutine_non_
|
|
call psb_errpush(info,name)
|
|
goto 9999
|
|
end if
|
|
|
|
! STEP 10: Compute V = {V(1),...,V(m)}
|
|
do i=1,nrep+1
|
|
idx = (i-1)*n+1
|
|
v_tot%v%v(:,idx:idx+n_add) = v(i)%v%v(:,1:n)
|
|
enddo
|
|
|
|
! STEP 11: X(m) = X(0) + V*Y(m)
|
|
call psb_geaxpby(done,psb_gedot(v_tot,h,desc_a,info),done,x,desc_a,info)
|
|
if (info /= psb_success_) then
|
|
info=psb_err_from_subroutine_non_
|
|
call psb_errpush(info,name)
|
|
goto 9999
|
|
end if
|
|
|
|
! END algorithm
|
|
|
|
if (itrace_ > 0) call log_conv(methdname,me,itx,ione,errnum,errden,deps)
|
|
|
|
call log_end(methdname,me,itx,itrace_,errnum,errden,deps,err=derr,iter=iter)
|
|
if (present(err)) err = derr
|
|
|
|
if (info == psb_success_) call psb_gefree(v,desc_a,info)
|
|
if (info == psb_success_) call psb_gefree(v_tot,desc_a,info)
|
|
if (info == psb_success_) call psb_gefree(w,desc_a,info)
|
|
if (info == psb_success_) deallocate(aux,h,stat=info)
|
|
if (info /= psb_success_) then
|
|
info=psb_err_from_subroutine_non_
|
|
call psb_errpush(info,name)
|
|
goto 9999
|
|
end if
|
|
|
|
call psb_erractionrestore(err_act)
|
|
return
|
|
|
|
9999 call psb_error_handler(err_act)
|
|
return
|
|
|
|
contains
|
|
|
|
! Minimize Frobenius norm
|
|
subroutine frobenius_norm_min()
|
|
|
|
implicit none
|
|
|
|
integer(psb_ipk_) :: lwork
|
|
real(psb_dpk_), allocatable :: work(:), beta_e1(:,:)
|
|
|
|
integer(psb_ipk_) :: m_h, n_h, mn
|
|
|
|
! Initialize params
|
|
m_h = (nrep+1)*n
|
|
n_h = nrep*n
|
|
mn = min(m_h,n_h)
|
|
lwork = max(1,mn+max(mn,n))
|
|
allocate(work(lwork))
|
|
|
|
! Compute E1*beta
|
|
allocate(beta_e1(m_h,n))
|
|
beta_e1 = dzero
|
|
beta_e1(1:n,1:n) = beta
|
|
|
|
! Compute min Frobenius norm
|
|
call dgels('N',m_h,n_h,n,h,m_h,beta_e1,m_h,work,lwork,info)
|
|
|
|
deallocate(work,beta_e1)
|
|
|
|
return
|
|
|
|
end subroutine frobenius_norm_min
|
|
|
|
end subroutine psb_dbgmres_multivect
|