Actual source code: baijfact4.c

  1: /*$Id: baijfact4.c,v 1.4 2001/03/23 23:22:07 balay Exp $*/
  2: /*
  3:     Factorization code for BAIJ format. 
  4: */
 5:  #include src/mat/impls/baij/seq/baij.h
 6:  #include src/inline/ilu.h

  8: /* ----------------------------------------------------------- */
 11: int MatLUFactorNumeric_SeqBAIJ_N(Mat A,Mat *B)
 12: {
 13:   Mat                C = *B;
 14:   Mat_SeqBAIJ        *a = (Mat_SeqBAIJ*)A->data,*b = (Mat_SeqBAIJ *)C->data;
 15:   IS                 isrow = b->row,isicol = b->icol;
 16:   int                *r,*ic,ierr,i,j,n = a->mbs,*bi = b->i,*bj = b->j;
 17:   int                *ajtmpold,*ajtmp,nz,row,bslog,*ai=a->i,*aj=a->j,k,flg;
 18:   int                *diag_offset=b->diag,diag,bs=a->bs,bs2 = a->bs2,*v_pivots,*pj;
 19:   MatScalar          *ba = b->a,*aa = a->a,*pv,*v,*rtmp,*multiplier,*v_work,*pc,*w;

 22:   ISGetIndices(isrow,&r);
 23:   ISGetIndices(isicol,&ic);
 24:   PetscMalloc(bs2*(n+1)*sizeof(MatScalar),&rtmp);
 25:   PetscMemzero(rtmp,bs2*(n+1)*sizeof(MatScalar));
 26:   /* generate work space needed by dense LU factorization */
 27:   PetscMalloc(bs*sizeof(int) + (bs+bs2)*sizeof(MatScalar),&v_work);
 28:   multiplier = v_work + bs;
 29:   v_pivots   = (int*)(multiplier + bs2);

 31:   /* flops in while loop */
 32:   bslog = 2*bs*bs2;

 34:   for (i=0; i<n; i++) {
 35:     nz    = bi[i+1] - bi[i];
 36:     ajtmp = bj + bi[i];
 37:     for  (j=0; j<nz; j++) {
 38:       PetscMemzero(rtmp+bs2*ajtmp[j],bs2*sizeof(MatScalar));
 39:     }
 40:     /* load in initial (unfactored row) */
 41:     nz       = ai[r[i]+1] - ai[r[i]];
 42:     ajtmpold = aj + ai[r[i]];
 43:     v        = aa + bs2*ai[r[i]];
 44:     for (j=0; j<nz; j++) {
 45:       PetscMemcpy(rtmp+bs2*ic[ajtmpold[j]],v+bs2*j,bs2*sizeof(MatScalar));
 46:     }
 47:     row = *ajtmp++;
 48:     while (row < i) {
 49:       pc = rtmp + bs2*row;
 50: /*      if (*pc) { */
 51:       for (flg=0,k=0; k<bs2; k++) { if (pc[k]!=0.0) { flg = 1; break; }}
 52:       if (flg) {
 53:         pv = ba + bs2*diag_offset[row];
 54:         pj = bj + diag_offset[row] + 1;
 55:         Kernel_A_gets_A_times_B(bs,pc,pv,multiplier);
 56:         nz = bi[row+1] - diag_offset[row] - 1;
 57:         pv += bs2;
 58:         for (j=0; j<nz; j++) {
 59:           Kernel_A_gets_A_minus_B_times_C(bs,rtmp+bs2*pj[j],pc,pv+bs2*j);
 60:         }
 61:         PetscLogFlops(bslog*(nz+1)-bs);
 62:       }
 63:         row = *ajtmp++;
 64:     }
 65:     /* finished row so stick it into b->a */
 66:     pv = ba + bs2*bi[i];
 67:     pj = bj + bi[i];
 68:     nz = bi[i+1] - bi[i];
 69:     for (j=0; j<nz; j++) {
 70:       PetscMemcpy(pv+bs2*j,rtmp+bs2*pj[j],bs2*sizeof(MatScalar));
 71:     }
 72:     diag = diag_offset[i] - bi[i];
 73:     /* invert diagonal block */
 74:     w = pv + bs2*diag;
 75:     Kernel_A_gets_inverse_A(bs,w,v_pivots,v_work);
 76:   }

 78:   PetscFree(rtmp);
 79:   PetscFree(v_work);
 80:   ISRestoreIndices(isicol,&ic);
 81:   ISRestoreIndices(isrow,&r);
 82:   C->factor = FACTOR_LU;
 83:   C->assembled = PETSC_TRUE;
 84:   PetscLogFlops(1.3333*bs*bs2*b->mbs); /* from inverting diagonal blocks */
 85:   return(0);
 86: }