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414 lines
14 KiB
Fortran
414 lines
14 KiB
Fortran
!!$
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!!$ Parallel Sparse BLAS v2.0
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!!$ (C) Copyright 2006 Salvatore Filippone University of Rome Tor Vergata
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!!$ Alfredo Buttari University of Rome Tor Vergata
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!!$
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!!$ Redistribution and use in source and binary forms, with or without
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!!$ modification, are permitted provided that the following conditions
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!!$ are met:
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!!$ 1. Redistributions of source code must retain the above copyright
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!!$ notice, this list of conditions and the following disclaimer.
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!!$ 2. Redistributions in binary form must reproduce the above copyright
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!!$ notice, this list of conditions, and the following disclaimer in the
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!!$ documentation and/or other materials provided with the distribution.
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!!$ 3. The name of the PSBLAS group or the names of its contributors may
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!!$ not be used to endorse or promote products derived from this
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!!$ software without specific written permission.
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!!$
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!!$ THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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!!$ ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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!!$ TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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!!$ PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE PSBLAS GROUP OR ITS CONTRIBUTORS
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!!$ BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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!!$ CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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!!$ SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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!!$ INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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!!$ CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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!!$ ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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!!$ POSSIBILITY OF SUCH DAMAGE.
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!!$
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!!$
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!!$ CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC
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!!$ C C
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!!$ C References: C
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!!$ C [1] Duff, I., Marrone, M., Radicati, G., and Vittoli, C. C
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!!$ C Level 3 basic linear algebra subprograms for sparse C
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!!$ C matrices: a user level interface C
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!!$ C ACM Trans. Math. Softw., 23(3), 379-401, 1997. C
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!!$ C C
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!!$ C C
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!!$ C [2] S. Filippone, M. Colajanni C
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!!$ C PSBLAS: A library for parallel linear algebra C
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!!$ C computation on sparse matrices C
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!!$ C ACM Trans. on Math. Softw., 26(4), 527-550, Dec. 2000. C
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!!$ C C
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!!$ C [3] M. Arioli, I. Duff, M. Ruiz C
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!!$ C Stopping criteria for iterative solvers C
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!!$ C SIAM J. Matrix Anal. Appl., Vol. 13, pp. 138-144, 1992 C
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!!$ C C
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!!$ C C
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!!$ C [4] R. Barrett et al C
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!!$ C Templates for the solution of linear systems C
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!!$ C SIAM, 1993
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!!$ C C
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!!$ C C
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!!$ CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC
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! File: psb_dcgstab.f90
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!
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! Subroutine: psb_dcgstab
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! This subroutine implements the CG Stabilized method.
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!
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! Parameters:
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! a - type(<psb_dspmat_type>). The sparse matrix containing A.
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! prec - type(<psb_prec_type>). The data structure containing the preconditioner.
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! b - real,dimension(:). The right hand side.
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! x - real,dimension(:). The vector of unknowns.
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! eps - real. The error tolerance.
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! desc_a - type(<psb_desc_type>). The communication descriptor.
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! info - integer. Eventually returns an error code.
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! itmax - integer(optional). The maximum number of iterations.
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! iter - integer(optional). The number of iterations performed.
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! err - real(optional). The error on return.
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! itrace - integer(optional). The unit to write messages onto.
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! istop - integer(optional). The stopping criterium.
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!
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Subroutine psb_dcgstab(a,prec,b,x,eps,desc_a,info,&
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&itmax,iter,err,itrace, istop)
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use psb_serial_mod
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use psb_descriptor_type
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use psb_prec_type
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use psb_psblas_mod
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use psb_tools_mod
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use psb_const_mod
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use psb_prec_mod
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use psb_error_mod
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Implicit None
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!!$ parameters
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Type(psb_dspmat_type), Intent(in) :: a
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Type(psb_dprec_type), Intent(in) :: prec
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Type(psb_desc_type), Intent(in) :: desc_a
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Real(Kind(1.d0)), Intent(in) :: b(:)
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Real(Kind(1.d0)), Intent(inout) :: x(:)
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Real(Kind(1.d0)), Intent(in) :: eps
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integer, intent(out) :: info
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Integer, Optional, Intent(in) :: itmax, itrace, istop
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Integer, Optional, Intent(out) :: iter
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Real(Kind(1.d0)), Optional, Intent(out) :: err
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!!$ Local data
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Real(Kind(1.d0)), Pointer :: aux(:),wwrk(:,:)
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Real(Kind(1.d0)), Pointer :: q(:),&
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& r(:), p(:), v(:), s(:), t(:), z(:), f(:)
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Integer, Pointer :: iperm(:), ipnull(:), ipsave(:)
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Real(Kind(1.d0)) ::rerr
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Integer ::litmax, liter, naux, m, mglob, it,itrac,&
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& nprows,npcols,myrow,mycol, n_row, n_col
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Character ::diagl, diagu
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Logical, Parameter :: debug = .false.
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Logical, Parameter :: exchange=.True., noexchange=.False., debug1 = .False.
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Integer, Parameter :: irmax = 8
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Integer :: itx, i, isvch, ich, icontxt, err_act, int_err(5),ii
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Integer :: listop
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Logical :: do_renum_left
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Real(Kind(1.d0)), Parameter :: one=1.d0, zero=0.d0, epstol=1.d-35
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Real(Kind(1.d0)) :: alpha, beta, rho, rho_old, rni, xni, bni, ani,&
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& sigma, omega, tau, rn0, bn2
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!!$ Integer istpb, istpe, ifctb, ifcte, imerr, irank, icomm,immb,imme
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!!$ Integer mpe_log_get_event_number,mpe_Describe_state,mpe_log_event
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character(len=20) :: name,ch_err
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info = 0
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name = 'psb_dcgstab'
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call psb_erractionsave(err_act)
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If (debug) Write(*,*) 'Entering PSB_DCGSTAB',present(istop)
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icontxt = desc_a%matrix_data(psb_ctxt_)
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CALL blacs_gridinfo(icontxt,nprows,npcols,myrow,mycol)
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if (debug) write(*,*) 'PSB_DCGSTAB: From GRIDINFO',nprows,npcols,myrow
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mglob = desc_a%matrix_data(psb_m_)
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n_row = desc_a%matrix_data(psb_n_row_)
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n_col = desc_a%matrix_data(psb_n_col_)
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If (Present(istop)) Then
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listop = istop
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Else
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listop = 1
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Endif
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!
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! LISTOP = 1: Normwise backward error, infinity norm
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! LISTOP = 2: ||r||/||b|| norm 2
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!
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If ((prec%prec < min_prec_).Or.(prec%prec > max_prec_) ) Then
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Write(0,*) 'PSB_CGSTAB: Invalid IPREC',prec%prec
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info=5002
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int_err(1)=prec%prec
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err=info
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call psb_errpush(info,name,i_err=int_err)
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goto 9999
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Endif
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if ((listop < 1 ).or.(listop > 2 ) ) then
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write(0,*) 'psb_bicgstab: invalid istop',listop
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info=5001
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int_err(1)=listop
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err=info
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call psb_errpush(info,name,i_err=int_err)
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goto 9999
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endif
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naux=6*n_col
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allocate(aux(naux),stat=info)
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call psb_alloc(mglob,8,wwrk,desc_a,info)
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call psb_asb(wwrk,desc_a,info)
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if (info /= 0) then
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info=4011
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call psb_errpush(info,name)
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goto 9999
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End If
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Q => WWRK(:,1)
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R => WWRK(:,2)
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P => WWRK(:,3)
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V => WWRK(:,4)
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F => WWRK(:,5)
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S => WWRK(:,6)
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T => WWRK(:,7)
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Z => WWRK(:,8)
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If (Present(itmax)) Then
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litmax = itmax
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Else
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litmax = 1000
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Endif
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If (Present(itrace)) Then
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itrac = itrace
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Else
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itrac = -1
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End If
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diagl = 'U'
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diagu = 'U'
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! Ensure global coherence for convergence checks.
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Call blacs_get(icontxt,16,isvch)
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ich = 1
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Call blacs_set(icontxt,16,ich)
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itx = 0
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If (listop == 1) Then
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ani = psb_nrmi(a,desc_a,info)
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bni = psb_amax(b,desc_a,info)
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Else If (listop == 2) Then
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bn2 = psb_nrm2(b,desc_a,info)
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Endif
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if (info /= 0) Then
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info=4011
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call psb_errpush(info,name)
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goto 9999
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End If
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restart: Do
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!!$
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!!$ r0 = b-Ax0
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!!$
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If (itx >= litmax) Exit restart
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it = 0
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Call psb_axpby(one,b,zero,r,desc_a,info)
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Call psb_spmm(-one,a,x,one,r,desc_a,info,work=aux)
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Call psb_axpby(one,r,zero,q,desc_a,info)
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if (info /= 0) Then
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info=4011
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call psb_errpush(info,name)
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goto 9999
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End If
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rho = zero
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If (debug) Write(*,*) 'On entry to AMAX: B: ',Size(b)
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!
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! Must always provide norm of R into RNI below for first check on
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! residual
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!
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If (listop == 1) Then
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rni = psb_amax(r,desc_a,info)
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xni = psb_amax(x,desc_a,info)
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Else If (listop == 2) Then
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rni = psb_nrm2(r,desc_a,info)
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Endif
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if (info /= 0) Then
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info=4011
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call psb_errpush(info,name)
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goto 9999
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End If
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If (itx == 0) Then
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rn0 = rni
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End If
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If (rn0 == 0.d0 ) Then
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If (itrac /= -1) Then
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If (myrow == 0) Write(itrac,*) 'BiCGSTAB: ',itx,rn0
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Endif
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Exit restart
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End If
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If (listop == 1) Then
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xni = psb_amax(x,desc_a,info)
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rerr = rni/(ani*xni+bni)
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If (itrac /= -1) Then
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If (myrow == 0) Write(itrac,'(a,i4,5(2x,es10.4))') 'bicgstab: ',itx,rerr,rni,bni,&
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&xni,ani
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Endif
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Else If (listop == 2) Then
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rerr = rni/bn2
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If (itrac /= -1) Then
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If (myrow == 0) Write(itrac,'(a,i4,3(2x,es10.4))') 'bicgstab: ',itx,rerr,rni,bn2
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Endif
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Endif
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if (info /= 0) Then
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info=4011
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call psb_errpush(info,name)
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goto 9999
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End If
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If (rerr<=eps) Then
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Exit restart
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End If
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iteration: Do
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it = it + 1
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itx = itx + 1
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If (debug) Write(*,*) 'Iteration: ',itx
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rho_old = rho
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rho = psb_dot(q,r,desc_a,info)
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!!$ call blacs_barrier(icontxt,'All') ! to be removed
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!!$ write(0,'(i2," rho old ",2(f,2x))')myrow,rho,rho_old
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!!$ call blacs_barrier(icontxt,'All') ! to be removed
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If (rho==zero) Then
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If (debug) Write(0,*) 'Bi-CGSTAB Itxation breakdown R',rho
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Exit iteration
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Endif
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If (it==1) Then
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Call psb_axpby(one,r,zero,p,desc_a,info)
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Else
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beta = (rho/rho_old)*(alpha/omega)
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Call psb_axpby(-omega,v,one,p,desc_a,info)
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Call psb_axpby(one,r,beta,p,desc_a,info)
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End If
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Call psb_prcaply(prec,p,f,desc_a,info,work=aux)
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Call psb_spmm(one,a,f,zero,v,desc_a,info,&
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& work=aux)
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sigma = psb_dot(q,v,desc_a,info)
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If (sigma==zero) Then
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If (debug) Write(0,*) 'Bi-CGSTAB Iteration breakdown S1', sigma
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Exit iteration
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Endif
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alpha = rho/sigma
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Call psb_axpby(one,r,zero,s,desc_a,info)
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if(info.ne.0) then
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call psb_errpush(4010,name,a_err='psb_axpby')
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goto 9999
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end if
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Call psb_axpby(-alpha,v,one,s,desc_a,info)
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if(info.ne.0) then
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call psb_errpush(4010,name,a_err='psb_axpby')
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goto 9999
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end if
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Call psb_prcaply(prec,s,z,desc_a,info,work=aux)
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if(info.ne.0) then
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call psb_errpush(4010,name,a_err='psb_prcaply')
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goto 9999
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end if
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Call psb_spmm(one,a,z,zero,t,desc_a,info,&
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& work=aux)
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if(info.ne.0) then
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call psb_errpush(4010,name,a_err='psb_spmm')
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goto 9999
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end if
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sigma = psb_dot(t,t,desc_a,info)
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If (sigma==zero) Then
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If (debug) Write(0,*) 'BI-CGSTAB ITERATION BREAKDOWN S2', sigma
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Exit iteration
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Endif
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tau = psb_dot(t,s,desc_a,info)
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omega = tau/sigma
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If (omega==zero) Then
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If (debug) Write(0,*) 'BI-CGSTAB ITERATION BREAKDOWN O',omega
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Exit iteration
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Endif
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Call psb_axpby(alpha,f,one,x,desc_a,info)
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Call psb_axpby(omega,z,one,x,desc_a,info)
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Call psb_axpby(one,s,zero,r,desc_a,info)
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Call psb_axpby(-omega,t,one,r,desc_a,info)
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If (listop == 1) Then
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rni = psb_amax(r,desc_a,info)
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xni = psb_amax(x,desc_a,info)
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rerr = rni/(ani*xni+bni)
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If (itrac /= -1) Then
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If (myrow == 0) Write(itrac,'(a,i4,5(2x,es10.4))') 'bicgstab: ',itx,rerr,rni,bni,&
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&xni,ani
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Endif
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Else If (listop == 2) Then
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rni = psb_nrm2(r,desc_a,info)
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rerr = rni/bn2
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If (itrac /= -1) Then
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If (myrow == 0) Write(itrac,'(a,i4,3(2x,es10.4)))') 'bicgstab: ',itx,rerr,rni,bn2
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Endif
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Endif
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If (rerr<=eps) Then
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Exit restart
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End If
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If (itx.Ge.litmax) Exit restart
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End Do iteration
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End Do restart
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If (Present(err)) err=rerr
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If (Present(iter)) iter = itx
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If (rerr>eps) Then
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Write(0,*) 'BI-CGSTAB FAILED TO CONVERGE TO ',EPS,&
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& ' IN ',ITX,' ITERATIONS '
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End If
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Deallocate(aux)
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Call psb_free(wwrk,desc_a,info)
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! restore external global coherence behaviour
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Call blacs_set(icontxt,16,isvch)
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!!$ imerr = MPE_Log_event( istpe, 0, "ed CGSTAB" )
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if(info/=0) then
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call psb_errpush(info,name)
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goto 9999
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end if
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call psb_erractionrestore(err_act)
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return
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9999 continue
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call psb_erractionrestore(err_act)
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if (err_act.eq.act_abort) then
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call psb_error(icontxt)
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return
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end if
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return
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End Subroutine psb_dcgstab
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