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Switched to right preconditioning.

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psblas3-type-indexed
Salvatore Filippone 18 years ago
parent be3237acef
commit 27aa15c809
1 changed files with 105 additions and 32 deletions
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135
krylov/psb_dgmresr.f90
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@ -3,6 +3,10 @@
!!$ (C) Copyright 2006 Salvatore Filippone University of Rome Tor Vergata
!!$ Alfredo Buttari University of Rome Tor Vergata
!!$
!!$ Contributions to this routine:
!!$ Daniela di Serafino Second University of Naples
!!$ Pasqua D'Ambra ICAR-CNR
!!$
!!$ Redistribution and use in source and binary forms, with or without
!!$ modification, are permitted provided that the following conditions
!!$ are met:
@ -63,7 +67,8 @@
! File: psb_dgmresr.f90
!
! Subroutine: psb_dgmres
! This subroutine implements the restarted GMRES method.
! This subroutine implements the restarted GMRES method with right
! preconditioning.
!
! Parameters:
! a - type(<psb_dspmat_type>). The sparse matrix containing A.
@ -98,8 +103,8 @@ Subroutine psb_dgmresr(a,prec,b,x,eps,desc_a,info,&
Integer, Optional, Intent(out) :: iter
Real(Kind(1.d0)), Optional, Intent(out) :: err
!!$ local data
Real(Kind(1.d0)), allocatable, target :: aux(:),w(:), v(:,:)
Real(Kind(1.d0)), allocatable :: c(:),s(:), h(:,:), rs(:)
Real(Kind(1.d0)), allocatable, target :: aux(:),w(:),w1(:), v(:,:)
Real(Kind(1.d0)), allocatable :: c(:),s(:), h(:,:), rs(:),rst(:),xt(:)
Real(Kind(1.d0)) :: rerr, scal, gm
Integer ::litmax, liter, naux, m, mglob, it,k, itrace_,&
& np,me, n_row, n_col, nl, int_err(5)
@ -133,7 +138,7 @@ Subroutine psb_dgmresr(a,prec,b,x,eps,desc_a,info,&
endif
!
! ISTOP_ = 1: Normwise backward error, infinity norm
! ISTOP_ = 2: ||r||/||b|| norm 2
! ISTOP_ = 2: ||r||/||b||, 2-norm
!
if ((istop_ < 1 ).or.(istop_ > 2 ) ) then
@ -173,21 +178,26 @@ Subroutine psb_dgmresr(a,prec,b,x,eps,desc_a,info,&
goto 9999
endif
naux=4*n_col
Allocate(aux(naux),h(nl+1,nl+1),&
&c(nl+1),s(nl+1),rs(nl+1), stat=info)
&c(nl+1),s(nl+1),rs(nl+1), rst(nl+1),stat=info)
if (info == 0) Call psb_geall(v,desc_a,info,n=nl+1)
if (info == 0) Call psb_geall(w,desc_a,info)
if (info == 0) Call psb_geall(w1,desc_a,info)
if (info == 0) Call psb_geall(xt,desc_a,info)
if (info == 0) Call psb_geasb(v,desc_a,info)
if (info == 0) Call psb_geasb(w,desc_a,info)
if (info == 0) Call psb_geasb(w1,desc_a,info)
if (info == 0) Call psb_geasb(xt,desc_a,info)
if (info.ne.0) Then
info=4011
call psb_errpush(info,name)
goto 9999
End If
if (debug) write(0,*) 'Size of V,W ',size(v),size(v,1),&
&size(w),size(w,1), size(v(:,1))
if (debug) write(0,*) 'Size of V,W,W1 ',size(v),size(v,1),&
&size(w),size(w,1),size(w1),size(w1,1), size(v(:,1))
! Ensure global coherence for convergence checks.
call psb_set_coher(ictxt,isvch)
@ -208,9 +218,11 @@ Subroutine psb_dgmresr(a,prec,b,x,eps,desc_a,info,&
diagu = 'u'
itx = 0
restart: Do
!!$
!!$ r0 = b-ax0
!!$
! compute r0 = b-ax0
! check convergence
! compute v1 = r0/||r0||_2
If (debug) Write(0,*) 'restart: ',itx,it
it = 0
Call psb_geaxpby(done,b,dzero,v(:,1),desc_a,info)
@ -219,19 +231,27 @@ Subroutine psb_dgmresr(a,prec,b,x,eps,desc_a,info,&
call psb_errpush(info,name)
goto 9999
End If
Call psb_spmm(-done,a,x,done,v(:,1),desc_a,info,work=aux)
if (info.ne.0) Then
info=4011
call psb_errpush(info,name)
goto 9999
End If
call psb_precaply(prec,v(:,1),desc_a,info)
rs(1) = psb_genrm2(v(:,1),desc_a,info)
if (info.ne.0) Then
info=4011
call psb_errpush(info,name)
goto 9999
End If
scal=done/rs(1) ! rs(1) MIGHT BE VERY SMALL - USE DSCAL TO DEAL WITH IT?
scal=done/rs(1)
If (debug) Write(0,*) 'on entry to amax: b: ',Size(b),rs(1),scal
!
! check convergence
!
if (istop_ == 1) then
rni = psb_geamax(v(:,1),desc_a,info)
xni = psb_geamax(x,desc_a,info)
@ -249,20 +269,27 @@ Subroutine psb_dgmresr(a,prec,b,x,eps,desc_a,info,&
If (rerr<=eps) Then
Exit restart
End If
If (itrace_ > 0) then
if ((mod(itx,itrace_)==0).and.(me == 0))&
& write(*,'(a,i4,3(2x,es10.4))') 'gmres(l): ',itx,rerr
end If
v(:,1) = v(:,1) * scal
If (itx.Ge.litmax) Exit restart
v(:,1) = v(:,1) * scal
!
! inner iterations
!
inner: Do i=1,nl
itx = itx + 1
Call psb_spmm(done,a,v(:,i),dzero,w,desc_a,info,work=aux)
call psb_precaply(prec,w,desc_a,info)
call psb_precaply(prec,v(:,i),w1,desc_a,info)
Call psb_spmm(done,a,w1,dzero,w,desc_a,info,work=aux)
!
!********** ADD ERROR HANDLING **************
do k = 1, i
h(k,i) = psb_gedot(v(:,k),w,desc_a,info)
@ -287,36 +314,80 @@ Subroutine psb_dgmresr(a,prec,b,x,eps,desc_a,info,&
h(i,i) = c(i)*h(i,i)+s(i)*h(i+1,i)
if (istop_ == 1) then
!da modificare, la norma infinito del residuo va calcolata a parte
rni = abs(rs(i+1))
xni = psb_geamax(x,desc_a,info)
!
! build x and then compute the residual and its infinity norm
!
rst = rs
xt = dzero
call dtrsm('l','u','n','n',i,1,done,h,size(h,1),rst,size(rst,1))
if (debug) write(0,*) 'Rebuild x-> RS:',rst(1:nl)
do k=1, i
call psb_geaxpby(rst(k),v(:,k),done,xt,desc_a,info)
end do
call psb_precaply(prec,xt,desc_a,info)
call psb_geaxpby(done,x,done,xt,desc_a,info)
call psb_geaxpby(done,b,dzero,w1,desc_a,info)
call psb_spmm(-done,a,xt,done,w1,desc_a,info,work=aux)
rni = psb_geamax(w1,desc_a,info)
xni = psb_geamax(xt,desc_a,info)
rerr = rni/(ani*xni+bni)
!
!********** ADD PSBLAS ERROR HANDLING **************
else if (istop_ == 2) then
!
! compute the residual 2-norm as byproduct of the solution
! procedure of the least-squares problem
!
rni = abs(rs(i+1))
rerr = rni/bn2
endif
if (rerr < eps ) then
if (debug) write(0,*) 'GMRES TRSM',i,size(h,1),nl
call dtrsm('l','u','n','n',i,1,done,h,size(h,1),rs,nl)
if (debug) write(0,*) 'Rebuild x-> RS:',rs(21:nl)
do k=1, i
call psb_geaxpby(rs(k),v(:,k),done,x,desc_a,info)
end do
if (istop_ == 1) then
x = xt
else if (istop_ == 2) then
!
! build x
!
call dtrsm('l','u','n','n',i,1,done,h,size(h,1),rs,size(rs,1))
if (debug) write(0,*) 'Rebuild x-> RS:',rs(21:nl)
w1 = dzero
do k=1, i
call psb_geaxpby(rs(k),v(:,k),done,w1,desc_a,info)
end do
call psb_precaply(prec,w1,w,desc_a,info)
call psb_geaxpby(done,w,done,x,desc_a,info)
end if
exit restart
end if
If (itrace_ > 0) then
if ((mod(itx,itrace_)==0).and.(me == 0))&
& write(*,'(a,i4,3(2x,es10.4))') 'gmres(l): ',itx,rerr
end If
end Do inner
if (debug) write(0,*) 'Before DTRSM :',rs(1:nl),i,size(h,1),nl
call dtrsm('l','u','n','n',nl,1,done,h,size(h,1),rs,nl)
if (debug) write(0,*) 'Rebuild x-> RS:',rs(21:nl)
do k=1, nl
call psb_geaxpby(rs(k),v(:,k),done,x,desc_a,info)
end do
if (istop_ == 1) then
x = xt
else if (istop_ == 2) then
!
! build x
!
call dtrsm('l','u','n','n',nl,1,done,h,size(h,1),rs,size(rs,1))
if (debug) write(0,*) 'Rebuild x-> RS:',rs(21:nl)
w1 = dzero
do k=1, nl
call psb_geaxpby(rs(k),v(:,k),done,w1,desc_a,info)
end do
call psb_precaply(prec,w1,w,desc_a,info)
call psb_geaxpby(done,w,done,x,desc_a,info)
end if
End Do restart
If (itrace_ > 0) then
@ -331,9 +402,11 @@ Subroutine psb_dgmresr(a,prec,b,x,eps,desc_a,info,&
End If
Deallocate(aux,h,c,s,rs, stat=info)
Deallocate(aux,h,c,s,rs,rst, stat=info)
Call psb_gefree(v,desc_a,info)
Call psb_gefree(w,desc_a,info)
Call psb_gefree(w1,desc_a,info)
Call psb_gefree(xt,desc_a,info)
! restore external global coherence behaviour
call psb_restore_coher(ictxt,isvch)

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