Date: 2022-08-02T03:13:51+00:00

Actual source code: baijsolvtrann.c

      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:   const PetscInt    *r,*c,*rout,*cout,*ai=a->i,*aj=a->j,*vi;
     10:   PetscInt          i,nz,j;
     11:   const PetscInt    n  =a->mbs,bs=A->rmap->bs,bs2=a->bs2;
     12:   const MatScalar   *aa=a->a,*v;
     13:   PetscScalar       *x,*t,*ls;
     14:   const PetscScalar *b;

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

     20:   ISGetIndices(isrow,&rout); r = rout;
     21:   ISGetIndices(iscol,&cout); c = cout;

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

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

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

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

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

     70: PetscErrorCode MatSolveTranspose_SeqBAIJ_N(Mat A,Vec bb,Vec xx)
     71: {
     72:   Mat_SeqBAIJ       *a   =(Mat_SeqBAIJ*)A->data;
     73:   IS                iscol=a->col,isrow=a->row;
     74:   const PetscInt    *r,*c,*rout,*cout;
     75:   const PetscInt    n=a->mbs,*ai=a->i,*aj=a->j,*vi,*diag=a->diag;
     76:   PetscInt          i,j,nz;
     77:   const PetscInt    bs =A->rmap->bs,bs2=a->bs2;
     78:   const MatScalar   *aa=a->a,*v;
     79:   PetscScalar       *x,*t,*ls;
     80:   const PetscScalar *b;

     82:   VecGetArrayRead(bb,&b);
     83:   VecGetArray(xx,&x);
     84:   t    = a->solve_work;

     86:   ISGetIndices(isrow,&rout); r = rout;
     87:   ISGetIndices(iscol,&cout); c = cout;

     89:   /* copy the b into temp work space according to permutation */
     90:   for (i=0; i<n; i++) {
     91:     for (j=0; j<bs; j++) {
     92:       t[i*bs+j] = b[c[i]*bs+j];
     93:     }
     94:   }

     96:   /* forward solve the upper triangular transpose */
     97:   ls = a->solve_work + A->cmap->n;
     98:   for (i=0; i<n; i++) {
     99:     PetscArraycpy(ls,t+i*bs,bs);
    100:     PetscKernel_w_gets_transA_times_v(bs,ls,aa+bs2*diag[i],t+i*bs);
    101:     v  = aa + bs2*(diag[i] - 1);
    102:     vi = aj + diag[i] - 1;
    103:     nz = diag[i] - diag[i+1] - 1;
    104:     for (j=0; j>-nz; j--) {
    105:       PetscKernel_v_gets_v_minus_transA_times_w(bs,t+bs*(vi[j]),v,t+i*bs);
    106:       v -= bs2;
    107:     }
    108:   }

    110:   /* backward solve the lower triangular transpose */
    111:   for (i=n-1; i>=0; i--) {
    112:     v  = aa + bs2*ai[i];
    113:     vi = aj + ai[i];
    114:     nz = ai[i+1] - ai[i];
    115:     for (j=0; j<nz; j++) {
    116:       PetscKernel_v_gets_v_minus_transA_times_w(bs,t+bs*(vi[j]),v,t+i*bs);
    117:       v += bs2;
    118:     }
    119:   }

    121:   /* copy t into x according to permutation */
    122:   for (i=0; i<n; i++) {
    123:     for (j=0; j<bs; j++) {
    124:       x[bs*r[i]+j]   = t[bs*i+j];
    125:     }
    126:   }

    128:   ISRestoreIndices(isrow,&rout);
    129:   ISRestoreIndices(iscol,&cout);
    130:   VecRestoreArrayRead(bb,&b);
    131:   VecRestoreArray(xx,&x);
    132:   PetscLogFlops(2.0*(a->bs2)*(a->nz) - A->rmap->bs*A->cmap->n);
    133:   return 0;
    134: }