Actual source code: baijsolvtrann.c
petsc-3.10.5 2019-03-28
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      1:  #include <../src/mat/impls/baij/seq/baij.h>
      2:  #include <petsc/private/kernels/blockinvert.h>

      4: /* ----------------------------------------------------------- */
      5: PetscErrorCode MatSolveTranspose_SeqBAIJ_N_inplace(Mat A,Vec bb,Vec xx)
      6: {
      7:   Mat_SeqBAIJ       *a   =(Mat_SeqBAIJ*)A->data;
      8:   IS                iscol=a->col,isrow=a->row;
      9:   PetscErrorCode    ierr;
     10:   const PetscInt    *r,*c,*rout,*cout,*ai=a->i,*aj=a->j,*vi;
     11:   PetscInt          i,nz,j;
     12:   const PetscInt    n  =a->mbs,bs=A->rmap->bs,bs2=a->bs2;
     13:   const MatScalar   *aa=a->a,*v;
     14:   PetscScalar       *x,*t,*ls;
     15:   const PetscScalar *b;

     18:   VecGetArrayRead(bb,&b);
     19:   VecGetArray(xx,&x);
     20:   t    = a->solve_work;

     22:   ISGetIndices(isrow,&rout); r = rout;
     23:   ISGetIndices(iscol,&cout); c = cout;

     25:   /* copy the b into temp work space according to permutation */
     26:   for (i=0; i<n; i++) {
     27:     for (j=0; j<bs; j++) {
     28:       t[i*bs+j] = b[c[i]*bs+j];
     29:     }
     30:   }

     33:   /* forward solve the upper triangular transpose */
     34:   ls = a->solve_work + A->cmap->n;
     35:   for (i=0; i<n; i++) {
     36:     PetscMemcpy(ls,t+i*bs,bs*sizeof(PetscScalar));
     37:     PetscKernel_w_gets_transA_times_v(bs,ls,aa+bs2*a->diag[i],t+i*bs);
     38:     v  = aa + bs2*(a->diag[i] + 1);
     39:     vi = aj + a->diag[i] + 1;
     40:     nz = ai[i+1] - a->diag[i] - 1;
     41:     while (nz--) {
     42:       PetscKernel_v_gets_v_minus_transA_times_w(bs,t+bs*(*vi++),v,t+i*bs);
     43:       v += bs2;
     44:     }
     45:   }

     47:   /* backward solve the lower triangular transpose */
     48:   for (i=n-1; i>=0; i--) {
     49:     v  = aa + bs2*ai[i];
     50:     vi = aj + ai[i];
     51:     nz = a->diag[i] - ai[i];
     52:     while (nz--) {
     53:       PetscKernel_v_gets_v_minus_transA_times_w(bs,t+bs*(*vi++),v,t+i*bs);
     54:       v += bs2;
     55:     }
     56:   }

     58:   /* copy t into x according to permutation */
     59:   for (i=0; i<n; i++) {
     60:     for (j=0; j<bs; j++) {
     61:       x[bs*r[i]+j]   = t[bs*i+j];
     62:     }
     63:   }

     65:   ISRestoreIndices(isrow,&rout);
     66:   ISRestoreIndices(iscol,&cout);
     67:   VecRestoreArrayRead(bb,&b);
     68:   VecRestoreArray(xx,&x);
     69:   PetscLogFlops(2.0*(a->bs2)*(a->nz) - A->rmap->bs*A->cmap->n);
     70:   return(0);
     71: }

     73: PetscErrorCode MatSolveTranspose_SeqBAIJ_N(Mat A,Vec bb,Vec xx)
     74: {
     75:   Mat_SeqBAIJ       *a   =(Mat_SeqBAIJ*)A->data;
     76:   IS                iscol=a->col,isrow=a->row;
     77:   PetscErrorCode    ierr;
     78:   const PetscInt    *r,*c,*rout,*cout;
     79:   const PetscInt    n=a->mbs,*ai=a->i,*aj=a->j,*vi,*diag=a->diag;
     80:   PetscInt          i,j,nz;
     81:   const PetscInt    bs =A->rmap->bs,bs2=a->bs2;
     82:   const MatScalar   *aa=a->a,*v;
     83:   PetscScalar       *x,*t,*ls;
     84:   const PetscScalar *b;

     87:   VecGetArrayRead(bb,&b);
     88:   VecGetArray(xx,&x);
     89:   t    = a->solve_work;

     91:   ISGetIndices(isrow,&rout); r = rout;
     92:   ISGetIndices(iscol,&cout); c = cout;

     94:   /* copy the b into temp work space according to permutation */
     95:   for (i=0; i<n; i++) {
     96:     for (j=0; j<bs; j++) {
     97:       t[i*bs+j] = b[c[i]*bs+j];
     98:     }
     99:   }

    102:   /* forward solve the upper triangular transpose */
    103:   ls = a->solve_work + A->cmap->n;
    104:   for (i=0; i<n; i++) {
    105:     PetscMemcpy(ls,t+i*bs,bs*sizeof(PetscScalar));
    106:     PetscKernel_w_gets_transA_times_v(bs,ls,aa+bs2*diag[i],t+i*bs);
    107:     v  = aa + bs2*(diag[i] - 1);
    108:     vi = aj + diag[i] - 1;
    109:     nz = diag[i] - diag[i+1] - 1;
    110:     for (j=0; j>-nz; j--) {
    111:       PetscKernel_v_gets_v_minus_transA_times_w(bs,t+bs*(vi[j]),v,t+i*bs);
    112:       v -= bs2;
    113:     }
    114:   }

    116:   /* backward solve the lower triangular transpose */
    117:   for (i=n-1; i>=0; i--) {
    118:     v  = aa + bs2*ai[i];
    119:     vi = aj + ai[i];
    120:     nz = ai[i+1] - ai[i];
    121:     for (j=0; j<nz; j++) {
    122:       PetscKernel_v_gets_v_minus_transA_times_w(bs,t+bs*(vi[j]),v,t+i*bs);
    123:       v += bs2;
    124:     }
    125:   }

    127:   /* copy t into x according to permutation */
    128:   for (i=0; i<n; i++) {
    129:     for (j=0; j<bs; j++) {
    130:       x[bs*r[i]+j]   = t[bs*i+j];
    131:     }
    132:   }

    134:   ISRestoreIndices(isrow,&rout);
    135:   ISRestoreIndices(iscol,&cout);
    136:   VecRestoreArrayRead(bb,&b);
    137:   VecRestoreArray(xx,&x);
    138:   PetscLogFlops(2.0*(a->bs2)*(a->nz) - A->rmap->bs*A->cmap->n);
    139:   return(0);
    140: }