Actual source code: baijsolvtrannat3.c

  1: #include <../src/mat/impls/baij/seq/baij.h>

  3: PetscErrorCode MatSolveTranspose_SeqBAIJ_3_NaturalOrdering_inplace(Mat A,Vec bb,Vec xx)
  4: {
  5:   Mat_SeqBAIJ     *a=(Mat_SeqBAIJ*)A->data;
  6:   const PetscInt  n=a->mbs,*vi,*ai=a->i,*aj=a->j,*diag=a->diag;
  7:   PetscInt        i,nz,idx,idt,oidx;
  8:   const MatScalar *aa=a->a,*v;
  9:   PetscScalar     s1,s2,s3,x1,x2,x3,*x;

 11:   VecCopy(bb,xx);
 12:   VecGetArray(xx,&x);

 14:   /* forward solve the U^T */
 15:   idx = 0;
 16:   for (i=0; i<n; i++) {

 18:     v = aa + 9*diag[i];
 19:     /* multiply by the inverse of the block diagonal */
 20:     x1 = x[idx];   x2 = x[1+idx]; x3    = x[2+idx];
 21:     s1 = v[0]*x1  +  v[1]*x2 +  v[2]*x3;
 22:     s2 = v[3]*x1  +  v[4]*x2 +  v[5]*x3;
 23:     s3 = v[6]*x1  +  v[7]*x2 + v[8]*x3;
 24:     v += 9;

 26:     vi = aj + diag[i] + 1;
 27:     nz = ai[i+1] - diag[i] - 1;
 28:     while (nz--) {
 29:       oidx       = 3*(*vi++);
 30:       x[oidx]   -= v[0]*s1  +  v[1]*s2 +  v[2]*s3;
 31:       x[oidx+1] -= v[3]*s1  +  v[4]*s2 +  v[5]*s3;
 32:       x[oidx+2] -= v[6]*s1 + v[7]*s2 + v[8]*s3;
 33:       v         += 9;
 34:     }
 35:     x[idx] = s1;x[1+idx] = s2; x[2+idx] = s3;
 36:     idx   += 3;
 37:   }
 38:   /* backward solve the L^T */
 39:   for (i=n-1; i>=0; i--) {
 40:     v   = aa + 9*diag[i] - 9;
 41:     vi  = aj + diag[i] - 1;
 42:     nz  = diag[i] - ai[i];
 43:     idt = 3*i;
 44:     s1  = x[idt];  s2 = x[1+idt]; s3 = x[2+idt];
 45:     while (nz--) {
 46:       idx       = 3*(*vi--);
 47:       x[idx]   -=  v[0]*s1 +  v[1]*s2 +  v[2]*s3;
 48:       x[idx+1] -=  v[3]*s1 +  v[4]*s2 +  v[5]*s3;
 49:       x[idx+2] -= v[6]*s1 + v[7]*s2 + v[8]*s3;
 50:       v        -= 9;
 51:     }
 52:   }
 53:   VecRestoreArray(xx,&x);
 54:   PetscLogFlops(2.0*9.0*(a->nz) - 3.0*A->cmap->n);
 55:   return 0;
 56: }

 58: PetscErrorCode MatSolveTranspose_SeqBAIJ_3_NaturalOrdering(Mat A,Vec bb,Vec xx)
 59: {
 60:   Mat_SeqBAIJ     *a=(Mat_SeqBAIJ*)A->data;
 61:   const PetscInt  n=a->mbs,*vi,*ai=a->i,*aj=a->j,*diag=a->diag;
 62:   PetscInt        nz,idx,idt,j,i,oidx;
 63:   const PetscInt  bs =A->rmap->bs,bs2=a->bs2;
 64:   const MatScalar *aa=a->a,*v;
 65:   PetscScalar     s1,s2,s3,x1,x2,x3,*x;

 67:   VecCopy(bb,xx);
 68:   VecGetArray(xx,&x);

 70:   /* forward solve the U^T */
 71:   idx = 0;
 72:   for (i=0; i<n; i++) {
 73:     v = aa + bs2*diag[i];
 74:     /* multiply by the inverse of the block diagonal */
 75:     x1 = x[idx];   x2 = x[1+idx];  x3 = x[2+idx];
 76:     s1 = v[0]*x1  +  v[1]*x2  + v[2]*x3;
 77:     s2 = v[3]*x1  +  v[4]*x2  + v[5]*x3;
 78:     s3 = v[6]*x1  +  v[7]*x2  + v[8]*x3;
 79:     v -= bs2;

 81:     vi = aj + diag[i] - 1;
 82:     nz = diag[i] - diag[i+1] - 1;
 83:     for (j=0; j>-nz; j--) {
 84:       oidx       = bs*vi[j];
 85:       x[oidx]   -= v[0]*s1  +  v[1]*s2  + v[2]*s3;
 86:       x[oidx+1] -= v[3]*s1  +  v[4]*s2  + v[5]*s3;
 87:       x[oidx+2] -= v[6]*s1  +  v[7]*s2  + v[8]*s3;
 88:       v         -= bs2;
 89:     }
 90:     x[idx] = s1;x[1+idx] = s2;  x[2+idx] = s3;
 91:     idx   += bs;
 92:   }
 93:   /* backward solve the L^T */
 94:   for (i=n-1; i>=0; i--) {
 95:     v   = aa + bs2*ai[i];
 96:     vi  = aj + ai[i];
 97:     nz  = ai[i+1] - ai[i];
 98:     idt = bs*i;
 99:     s1  = x[idt];  s2 = x[1+idt];  s3 = x[2+idt];
100:     for (j=0; j<nz; j++) {
101:       idx       = bs*vi[j];
102:       x[idx]   -= v[0]*s1  +  v[1]*s2  + v[2]*s3;
103:       x[idx+1] -= v[3]*s1  +  v[4]*s2  + v[5]*s3;
104:       x[idx+2] -= v[6]*s1  +  v[7]*s2  + v[8]*s3;
105:       v        += bs2;
106:     }
107:   }
108:   VecRestoreArray(xx,&x);
109:   PetscLogFlops(2.0*bs2*(a->nz) - bs*A->cmap->n);
110:   return 0;
111: }