/*  bicgstabl.c  */

#include "../Iter.h"

/*--------------------------------------------------------------------*/
/*
   ---------------------------------------------------------------------
   purpose -- to solve a unsymmetric real matrix equation

               Ax=b
   using left preconditioned BiCGSTAB 

      x       -- Initial guess
      A       -- Input matrix
      M       -- Front Matrix as the preconditioner
      b       -- Right-hand side
      tol     -- Convergence tolerance
      type -- type of entries
         SPOOLES_REAL or SPOOLES_COMPLEX
      symmetryflag -- symmetry of the matrix
         SPOOLES_SYMMETRIC, SPOOLES_HERMITIAN or SPOOLES_NONSYMMETRIC
      nrhs    -- number of right hand sides
      msglvl  -- message level
      msgFile -- message file

      return value  -- error flag

   created -- 98spe10   wpt
   ---------------------------------------------------------------------
*/

int
bicgstabl (
   int             n_matrixSize,
   int             type,
   int             symmetryflag,
   InpMtx          *mtxA,
   FrontMtx        *Precond,
   DenseMtx        *mtxX,
   DenseMtx        *mtxB,
   int             itermax,
   double          convergetol,
   int             msglvl,
   FILE            *msgFile
 )
{
Chv             *chv, *rootchv ;
ChvManager      *chvmanager ;
DenseMtx        *mtxZ ;
DenseMtx        *vecP, *vecR, *vecR0, *vecT,  *vecV, *vecW;
DenseMtx        *vecX, *vecY, *vecZ ;
double          Alpha, Beta, Init_norm, Omega, ratio, Res_norm, Rho, Rho_new, Rtmp, Rtmp2;
double          t1, t2,  cpus[9] ;
double          one[2] = {1.0, 0.0}, zero[2]={0.0, 0.0} ;
double          Tiny = 0.1e-28;
int             Iter, Imv, neqns;
int             stats[6] ;




neqns = n_matrixSize;

/*
   --------------------
   init the vectors in bicgstab
   --------------------
*/
vecP = DenseMtx_new() ;
DenseMtx_init(vecP, type, 0, 0, neqns, 1, 1, neqns) ;

vecR = DenseMtx_new() ;
DenseMtx_init(vecR, type, 0, 0, neqns, 1, 1, neqns) ;

vecR0 = DenseMtx_new() ;
DenseMtx_init(vecR0, type, 0, 0, neqns, 1, 1, neqns) ;

vecT = DenseMtx_new() ;
DenseMtx_init(vecT, type, 0, 0, neqns, 1, 1, neqns) ;

vecV = DenseMtx_new() ;
DenseMtx_init(vecV, type, 0, 0, neqns, 1, 1, neqns) ;

vecW = DenseMtx_new() ;
DenseMtx_init(vecW, type, 0, 0, neqns, 1, 1, neqns) ;

vecX = DenseMtx_new() ;
DenseMtx_init(vecX, type, 0, 0, neqns, 1, 1, neqns) ;

vecY = DenseMtx_new() ;
DenseMtx_init(vecY, type, 0, 0, neqns, 1, 1, neqns) ;

vecZ = DenseMtx_new() ;
DenseMtx_init(vecZ, type, 0, 0, neqns, 1, 1, neqns) ;



/*
   --------------------------
   Initialize the iterations
   --------------------------
*/
/*          ----     Set initial guess as zero  ----               */
DenseMtx_zero(vecX) ;

DenseMtx_colCopy(vecT, 0, mtxB, 0);
/*                                                         */
    FrontMtx_solve(Precond, vecR, vecT, Precond->manager,
               cpus, msglvl, msgFile) ;
/*                                                      */




Init_norm = DenseMtx_twoNormOfColumn(vecR,0);
if ( Init_norm == 0.0 ){
  Init_norm = 1.0; 
};

ratio = 1.0;

DenseMtx_colCopy(vecR0, 0, vecR, 0);

  fprintf(msgFile, "\n BiCGSTAB Initial norm: %6.2e ", Init_norm ) ;
  fprintf(msgFile, "\n BiCGSTAB Conveg. Control: %6.2e ", convergetol ) ;

/*

*/
Rho     = 1.0;
Alpha   = 1.0;
Omega   = 1.0;
DenseMtx_zero(vecV) ;
DenseMtx_zero(vecP) ;
/*
   ------------------------------
   
   ------------------------------
*/

MARKTIME(t1) ;
Iter = 0;
Imv  = 0;

/*
   -----------------
   factor the matrix
   -----------------
*/
while ( ratio > convergetol && Iter <= itermax )
  {
    Iter++;
    DenseMtx_colDotProduct(vecR0, 0, vecR, 0, &Rho_new);
    Beta    = (Rho_new / (Rho+Tiny)) * (Alpha / (Omega+Tiny));
    Rho     = Rho_new;

/*  DenseMtx_axpy(vecP, vecV, -Omega); */
    Rtmp=-Omega;
    DenseMtx_colGenAxpy(one, vecP, 0, &Rtmp, vecV, 0);
/*  DenseMtx_aypx(vecP, vecR, Beta); */
    DenseMtx_colGenAxpy(&Beta, vecP, 0, one, vecR, 0);
/*                                                       
    DenseMtx_zero(vecY) ;
    InpMtx_nonsym_mmm(mtxA, vecY, one, vecP) ;
*/
      switch ( symmetryflag ) {
      case SPOOLES_SYMMETRIC : 
	InpMtx_sym_gmmm(mtxA, zero, vecY, one, vecP) ;
	break ;
      case SPOOLES_HERMITIAN :
	fprintf(msgFile, "\n BiCGSTABL Matrix type wrong");
	fprintf(msgFile, "\n Fatal error");
	goto end;
      case SPOOLES_NONSYMMETRIC :
	InpMtx_nonsym_gmmm(mtxA, zero, vecY, one, vecP) ;
	break ;
      default :
	fprintf(msgFile, "\n BiCGSTABL Matrix type wrong");
	fprintf(msgFile, "\n Fatal error");
	goto end;
      }
/*                                                         */
    FrontMtx_solve(Precond, vecV, vecY, Precond->manager,
               cpus, msglvl, msgFile) ;
    Imv++;
/*                                                          */
    DenseMtx_colDotProduct(vecR0, 0, vecV, 0, &Rtmp);
    Alpha = Rho / (Rtmp+Tiny);
/*                                                         */
    Rtmp=-Alpha;
    DenseMtx_colGenAxpy(one, vecR,  0, &Rtmp, vecV, 0);
/*                                                       
    DenseMtx_zero(vecZ) ;
    InpMtx_nonsym_mmm(mtxA, vecZ, one, vecR) ;
*/
      switch ( symmetryflag ) {
      case SPOOLES_SYMMETRIC : 
	InpMtx_sym_gmmm(mtxA, zero, vecZ, one, vecR) ;
	break ;
      case SPOOLES_HERMITIAN :
	fprintf(msgFile, "\n BiCGSTABL Matrix type wrong");
	fprintf(msgFile, "\n Fatal error");
	goto end;
      case SPOOLES_NONSYMMETRIC :
	InpMtx_nonsym_gmmm(mtxA, zero, vecZ, one, vecR) ;
	break ;
      default :
	fprintf(msgFile, "\n BiCGSTABL Matrix type wrong");
	fprintf(msgFile, "\n Fatal error");
	goto end;
      }
/*                                                         */
    FrontMtx_solve(Precond, vecT, vecZ, Precond->manager,
               cpus, msglvl, msgFile) ;
    Imv++;
/*                                                         */

    DenseMtx_colDotProduct(vecT, 0, vecR, 0, &Rtmp);
    DenseMtx_colDotProduct(vecT, 0, vecT, 0, &Rtmp2);
    Omega = Rtmp/(Rtmp2+Tiny);
    DenseMtx_colGenAxpy(one, vecX, 0, &Alpha, vecP, 0);
    DenseMtx_colGenAxpy(one, vecX, 0, &Omega, vecR, 0);
    /*                                                */
    Rtmp=-Omega;
    DenseMtx_colGenAxpy(one, vecR, 0, &Rtmp, vecT, 0);
    Res_norm =  DenseMtx_twoNormOfColumn(vecR,0);
    ratio = Res_norm/Init_norm;
    fprintf(msgFile, "\n\n At iteration %d"
	    "  the convergence ratio is  %12.4e"
	    "\n Residual norm is %6.2e", 
	    Imv, ratio, Res_norm) ;
  }
/*            End of while loop              */
MARKTIME(t2) ;
fprintf(msgFile, "\n CPU  : Converges in time: %8.3f ", t2 - t1) ;
fprintf(msgFile, "\n # iterations = %d", Imv) ;

fprintf(msgFile, "\n\n after BICGSTABL") ;
DenseMtx_colCopy(mtxX, 0, vecX, 0);

/*
 
   ------------------------
   free the working storage
   ------------------------
*/
end:

DenseMtx_free(vecP) ;
DenseMtx_free(vecR) ;
DenseMtx_free(vecR0) ;
DenseMtx_free(vecT) ;
DenseMtx_free(vecV) ;
DenseMtx_free(vecW) ;
DenseMtx_free(vecX) ;
DenseMtx_free(vecY) ;
DenseMtx_free(vecZ) ;

fprintf(msgFile, "\n") ;

return(1) ; }

/*--------------------------------------------------------------------*/