1*2c733ed4SBarry Smith #include <../src/mat/impls/baij/seq/baij.h> 2*2c733ed4SBarry Smith 3*2c733ed4SBarry Smith PetscErrorCode MatSolveTranspose_SeqBAIJ_2_NaturalOrdering_inplace(Mat A,Vec bb,Vec xx) 4*2c733ed4SBarry Smith { 5*2c733ed4SBarry Smith Mat_SeqBAIJ *a=(Mat_SeqBAIJ*)A->data; 6*2c733ed4SBarry Smith PetscErrorCode ierr; 7*2c733ed4SBarry Smith PetscInt i,nz,idx,idt,oidx; 8*2c733ed4SBarry Smith const PetscInt *diag = a->diag,*vi,n=a->mbs,*ai=a->i,*aj=a->j; 9*2c733ed4SBarry Smith const MatScalar *aa =a->a,*v; 10*2c733ed4SBarry Smith PetscScalar s1,s2,x1,x2,*x; 11*2c733ed4SBarry Smith 12*2c733ed4SBarry Smith PetscFunctionBegin; 13*2c733ed4SBarry Smith ierr = VecCopy(bb,xx);CHKERRQ(ierr); 14*2c733ed4SBarry Smith ierr = VecGetArray(xx,&x);CHKERRQ(ierr); 15*2c733ed4SBarry Smith 16*2c733ed4SBarry Smith /* forward solve the U^T */ 17*2c733ed4SBarry Smith idx = 0; 18*2c733ed4SBarry Smith for (i=0; i<n; i++) { 19*2c733ed4SBarry Smith 20*2c733ed4SBarry Smith v = aa + 4*diag[i]; 21*2c733ed4SBarry Smith /* multiply by the inverse of the block diagonal */ 22*2c733ed4SBarry Smith x1 = x[idx]; x2 = x[1+idx]; 23*2c733ed4SBarry Smith s1 = v[0]*x1 + v[1]*x2; 24*2c733ed4SBarry Smith s2 = v[2]*x1 + v[3]*x2; 25*2c733ed4SBarry Smith v += 4; 26*2c733ed4SBarry Smith 27*2c733ed4SBarry Smith vi = aj + diag[i] + 1; 28*2c733ed4SBarry Smith nz = ai[i+1] - diag[i] - 1; 29*2c733ed4SBarry Smith while (nz--) { 30*2c733ed4SBarry Smith oidx = 2*(*vi++); 31*2c733ed4SBarry Smith x[oidx] -= v[0]*s1 + v[1]*s2; 32*2c733ed4SBarry Smith x[oidx+1] -= v[2]*s1 + v[3]*s2; 33*2c733ed4SBarry Smith v += 4; 34*2c733ed4SBarry Smith } 35*2c733ed4SBarry Smith x[idx] = s1;x[1+idx] = s2; 36*2c733ed4SBarry Smith idx += 2; 37*2c733ed4SBarry Smith } 38*2c733ed4SBarry Smith /* backward solve the L^T */ 39*2c733ed4SBarry Smith for (i=n-1; i>=0; i--) { 40*2c733ed4SBarry Smith v = aa + 4*diag[i] - 4; 41*2c733ed4SBarry Smith vi = aj + diag[i] - 1; 42*2c733ed4SBarry Smith nz = diag[i] - ai[i]; 43*2c733ed4SBarry Smith idt = 2*i; 44*2c733ed4SBarry Smith s1 = x[idt]; s2 = x[1+idt]; 45*2c733ed4SBarry Smith while (nz--) { 46*2c733ed4SBarry Smith idx = 2*(*vi--); 47*2c733ed4SBarry Smith x[idx] -= v[0]*s1 + v[1]*s2; 48*2c733ed4SBarry Smith x[idx+1] -= v[2]*s1 + v[3]*s2; 49*2c733ed4SBarry Smith v -= 4; 50*2c733ed4SBarry Smith } 51*2c733ed4SBarry Smith } 52*2c733ed4SBarry Smith ierr = VecRestoreArray(xx,&x);CHKERRQ(ierr); 53*2c733ed4SBarry Smith ierr = PetscLogFlops(2.0*4.0*(a->nz) - 2.0*A->cmap->n);CHKERRQ(ierr); 54*2c733ed4SBarry Smith PetscFunctionReturn(0); 55*2c733ed4SBarry Smith } 56*2c733ed4SBarry Smith 57*2c733ed4SBarry Smith PetscErrorCode MatSolveTranspose_SeqBAIJ_2_NaturalOrdering(Mat A,Vec bb,Vec xx) 58*2c733ed4SBarry Smith { 59*2c733ed4SBarry Smith Mat_SeqBAIJ *a=(Mat_SeqBAIJ*)A->data; 60*2c733ed4SBarry Smith PetscErrorCode ierr; 61*2c733ed4SBarry Smith const PetscInt n=a->mbs,*vi,*ai=a->i,*aj=a->j,*diag=a->diag; 62*2c733ed4SBarry Smith PetscInt nz,idx,idt,j,i,oidx; 63*2c733ed4SBarry Smith const PetscInt bs =A->rmap->bs,bs2=a->bs2; 64*2c733ed4SBarry Smith const MatScalar *aa=a->a,*v; 65*2c733ed4SBarry Smith PetscScalar s1,s2,x1,x2,*x; 66*2c733ed4SBarry Smith 67*2c733ed4SBarry Smith PetscFunctionBegin; 68*2c733ed4SBarry Smith ierr = VecCopy(bb,xx);CHKERRQ(ierr); 69*2c733ed4SBarry Smith ierr = VecGetArray(xx,&x);CHKERRQ(ierr); 70*2c733ed4SBarry Smith 71*2c733ed4SBarry Smith /* forward solve the U^T */ 72*2c733ed4SBarry Smith idx = 0; 73*2c733ed4SBarry Smith for (i=0; i<n; i++) { 74*2c733ed4SBarry Smith v = aa + bs2*diag[i]; 75*2c733ed4SBarry Smith /* multiply by the inverse of the block diagonal */ 76*2c733ed4SBarry Smith x1 = x[idx]; x2 = x[1+idx]; 77*2c733ed4SBarry Smith s1 = v[0]*x1 + v[1]*x2; 78*2c733ed4SBarry Smith s2 = v[2]*x1 + v[3]*x2; 79*2c733ed4SBarry Smith v -= bs2; 80*2c733ed4SBarry Smith 81*2c733ed4SBarry Smith vi = aj + diag[i] - 1; 82*2c733ed4SBarry Smith nz = diag[i] - diag[i+1] - 1; 83*2c733ed4SBarry Smith for (j=0; j>-nz; j--) { 84*2c733ed4SBarry Smith oidx = bs*vi[j]; 85*2c733ed4SBarry Smith x[oidx] -= v[0]*s1 + v[1]*s2; 86*2c733ed4SBarry Smith x[oidx+1] -= v[2]*s1 + v[3]*s2; 87*2c733ed4SBarry Smith v -= bs2; 88*2c733ed4SBarry Smith } 89*2c733ed4SBarry Smith x[idx] = s1;x[1+idx] = s2; 90*2c733ed4SBarry Smith idx += bs; 91*2c733ed4SBarry Smith } 92*2c733ed4SBarry Smith /* backward solve the L^T */ 93*2c733ed4SBarry Smith for (i=n-1; i>=0; i--) { 94*2c733ed4SBarry Smith v = aa + bs2*ai[i]; 95*2c733ed4SBarry Smith vi = aj + ai[i]; 96*2c733ed4SBarry Smith nz = ai[i+1] - ai[i]; 97*2c733ed4SBarry Smith idt = bs*i; 98*2c733ed4SBarry Smith s1 = x[idt]; s2 = x[1+idt]; 99*2c733ed4SBarry Smith for (j=0; j<nz; j++) { 100*2c733ed4SBarry Smith idx = bs*vi[j]; 101*2c733ed4SBarry Smith x[idx] -= v[0]*s1 + v[1]*s2; 102*2c733ed4SBarry Smith x[idx+1] -= v[2]*s1 + v[3]*s2; 103*2c733ed4SBarry Smith v += bs2; 104*2c733ed4SBarry Smith } 105*2c733ed4SBarry Smith } 106*2c733ed4SBarry Smith ierr = VecRestoreArray(xx,&x);CHKERRQ(ierr); 107*2c733ed4SBarry Smith ierr = PetscLogFlops(2.0*bs2*(a->nz) - bs*A->cmap->n);CHKERRQ(ierr); 108*2c733ed4SBarry Smith PetscFunctionReturn(0); 109*2c733ed4SBarry Smith } 110