xref: /petsc/src/mat/impls/baij/seq/baijsolvnat5.c (revision ccb4e88a40f0b86eaeca07ff64c64e4de2fae686)
1 #include <../src/mat/impls/baij/seq/baij.h>
2 #include <petsc/private/kernels/blockinvert.h>
3 
4 PetscErrorCode MatSolve_SeqBAIJ_5_NaturalOrdering_inplace(Mat A,Vec bb,Vec xx)
5 {
6   Mat_SeqBAIJ       *a   = (Mat_SeqBAIJ*)A->data;
7   const PetscInt    *diag=a->diag,n=a->mbs,*vi,*ai=a->i,*aj=a->j;
8   PetscInt          i,nz,idx,idt,jdx;
9   PetscErrorCode    ierr;
10   const MatScalar   *aa=a->a,*v;
11   PetscScalar       *x,s1,s2,s3,s4,s5,x1,x2,x3,x4,x5;
12   const PetscScalar *b;
13 
14   PetscFunctionBegin;
15   ierr = VecGetArrayRead(bb,&b);CHKERRQ(ierr);
16   ierr = VecGetArray(xx,&x);CHKERRQ(ierr);
17   /* forward solve the lower triangular */
18   idx  = 0;
19   x[0] = b[idx]; x[1] = b[1+idx]; x[2] = b[2+idx]; x[3] = b[3+idx];x[4] = b[4+idx];
20   for (i=1; i<n; i++) {
21     v   =  aa + 25*ai[i];
22     vi  =  aj + ai[i];
23     nz  =  diag[i] - ai[i];
24     idx =  5*i;
25     s1  =  b[idx];s2 = b[1+idx];s3 = b[2+idx];s4 = b[3+idx];s5 = b[4+idx];
26     while (nz--) {
27       jdx = 5*(*vi++);
28       x1  = x[jdx];x2 = x[1+jdx];x3 = x[2+jdx];x4 = x[3+jdx];x5 = x[4+jdx];
29       s1 -= v[0]*x1 + v[5]*x2 + v[10]*x3  + v[15]*x4 + v[20]*x5;
30       s2 -= v[1]*x1 + v[6]*x2 + v[11]*x3  + v[16]*x4 + v[21]*x5;
31       s3 -= v[2]*x1 + v[7]*x2 + v[12]*x3  + v[17]*x4 + v[22]*x5;
32       s4 -= v[3]*x1 + v[8]*x2 + v[13]*x3  + v[18]*x4 + v[23]*x5;
33       s5 -= v[4]*x1 + v[9]*x2 + v[14]*x3  + v[19]*x4 + v[24]*x5;
34       v  += 25;
35     }
36     x[idx]   = s1;
37     x[1+idx] = s2;
38     x[2+idx] = s3;
39     x[3+idx] = s4;
40     x[4+idx] = s5;
41   }
42   /* backward solve the upper triangular */
43   for (i=n-1; i>=0; i--) {
44     v   = aa + 25*diag[i] + 25;
45     vi  = aj + diag[i] + 1;
46     nz  = ai[i+1] - diag[i] - 1;
47     idt = 5*i;
48     s1  = x[idt];  s2 = x[1+idt];
49     s3  = x[2+idt];s4 = x[3+idt]; s5 = x[4+idt];
50     while (nz--) {
51       idx = 5*(*vi++);
52       x1  = x[idx];   x2 = x[1+idx];x3    = x[2+idx]; x4 = x[3+idx]; x5 = x[4+idx];
53       s1 -= v[0]*x1 + v[5]*x2 + v[10]*x3  + v[15]*x4 + v[20]*x5;
54       s2 -= v[1]*x1 + v[6]*x2 + v[11]*x3  + v[16]*x4 + v[21]*x5;
55       s3 -= v[2]*x1 + v[7]*x2 + v[12]*x3  + v[17]*x4 + v[22]*x5;
56       s4 -= v[3]*x1 + v[8]*x2 + v[13]*x3  + v[18]*x4 + v[23]*x5;
57       s5 -= v[4]*x1 + v[9]*x2 + v[14]*x3  + v[19]*x4 + v[24]*x5;
58       v  += 25;
59     }
60     v        = aa + 25*diag[i];
61     x[idt]   = v[0]*s1 + v[5]*s2 + v[10]*s3  + v[15]*s4 + v[20]*s5;
62     x[1+idt] = v[1]*s1 + v[6]*s2 + v[11]*s3  + v[16]*s4 + v[21]*s5;
63     x[2+idt] = v[2]*s1 + v[7]*s2 + v[12]*s3  + v[17]*s4 + v[22]*s5;
64     x[3+idt] = v[3]*s1 + v[8]*s2 + v[13]*s3  + v[18]*s4 + v[23]*s5;
65     x[4+idt] = v[4]*s1 + v[9]*s2 + v[14]*s3  + v[19]*s4 + v[24]*s5;
66   }
67 
68   ierr = VecRestoreArrayRead(bb,&b);CHKERRQ(ierr);
69   ierr = VecRestoreArray(xx,&x);CHKERRQ(ierr);
70   ierr = PetscLogFlops(2.0*25*(a->nz) - 5.0*A->cmap->n);CHKERRQ(ierr);
71   PetscFunctionReturn(0);
72 }
73 
74 PetscErrorCode MatSolve_SeqBAIJ_5_NaturalOrdering(Mat A,Vec bb,Vec xx)
75 {
76   Mat_SeqBAIJ       *a = (Mat_SeqBAIJ*)A->data;
77   const PetscInt    n  = a->mbs,*vi,*ai=a->i,*aj=a->j,*adiag=a->diag;
78   PetscInt          i,k,nz,idx,idt,jdx;
79   PetscErrorCode    ierr;
80   const MatScalar   *aa=a->a,*v;
81   PetscScalar       *x,s1,s2,s3,s4,s5,x1,x2,x3,x4,x5;
82   const PetscScalar *b;
83 
84   PetscFunctionBegin;
85   ierr = VecGetArrayRead(bb,&b);CHKERRQ(ierr);
86   ierr = VecGetArray(xx,&x);CHKERRQ(ierr);
87   /* forward solve the lower triangular */
88   idx  = 0;
89   x[0] = b[idx]; x[1] = b[1+idx]; x[2] = b[2+idx]; x[3] = b[3+idx];x[4] = b[4+idx];
90   for (i=1; i<n; i++) {
91     v   = aa + 25*ai[i];
92     vi  = aj + ai[i];
93     nz  = ai[i+1] - ai[i];
94     idx = 5*i;
95     s1  = b[idx];s2 = b[1+idx];s3 = b[2+idx];s4 = b[3+idx];s5 = b[4+idx];
96     for (k=0; k<nz; k++) {
97       jdx = 5*vi[k];
98       x1  = x[jdx];x2 = x[1+jdx];x3 = x[2+jdx];x4 = x[3+jdx];x5 = x[4+jdx];
99       s1 -= v[0]*x1 + v[5]*x2 + v[10]*x3  + v[15]*x4 + v[20]*x5;
100       s2 -= v[1]*x1 + v[6]*x2 + v[11]*x3  + v[16]*x4 + v[21]*x5;
101       s3 -= v[2]*x1 + v[7]*x2 + v[12]*x3  + v[17]*x4 + v[22]*x5;
102       s4 -= v[3]*x1 + v[8]*x2 + v[13]*x3  + v[18]*x4 + v[23]*x5;
103       s5 -= v[4]*x1 + v[9]*x2 + v[14]*x3  + v[19]*x4 + v[24]*x5;
104       v  += 25;
105     }
106     x[idx]   = s1;
107     x[1+idx] = s2;
108     x[2+idx] = s3;
109     x[3+idx] = s4;
110     x[4+idx] = s5;
111   }
112 
113   /* backward solve the upper triangular */
114   for (i=n-1; i>=0; i--) {
115     v   = aa + 25*(adiag[i+1]+1);
116     vi  = aj + adiag[i+1]+1;
117     nz  = adiag[i] - adiag[i+1]-1;
118     idt = 5*i;
119     s1  = x[idt];  s2 = x[1+idt];
120     s3  = x[2+idt];s4 = x[3+idt]; s5 = x[4+idt];
121     for (k=0; k<nz; k++) {
122       idx = 5*vi[k];
123       x1  = x[idx];   x2 = x[1+idx];x3    = x[2+idx]; x4 = x[3+idx]; x5 = x[4+idx];
124       s1 -= v[0]*x1 + v[5]*x2 + v[10]*x3  + v[15]*x4 + v[20]*x5;
125       s2 -= v[1]*x1 + v[6]*x2 + v[11]*x3  + v[16]*x4 + v[21]*x5;
126       s3 -= v[2]*x1 + v[7]*x2 + v[12]*x3  + v[17]*x4 + v[22]*x5;
127       s4 -= v[3]*x1 + v[8]*x2 + v[13]*x3  + v[18]*x4 + v[23]*x5;
128       s5 -= v[4]*x1 + v[9]*x2 + v[14]*x3  + v[19]*x4 + v[24]*x5;
129       v  += 25;
130     }
131     /* x = inv_diagonal*x */
132     x[idt]   = v[0]*s1 + v[5]*s2 + v[10]*s3  + v[15]*s4 + v[20]*s5;
133     x[1+idt] = v[1]*s1 + v[6]*s2 + v[11]*s3  + v[16]*s4 + v[21]*s5;
134     x[2+idt] = v[2]*s1 + v[7]*s2 + v[12]*s3  + v[17]*s4 + v[22]*s5;
135     x[3+idt] = v[3]*s1 + v[8]*s2 + v[13]*s3  + v[18]*s4 + v[23]*s5;
136     x[4+idt] = v[4]*s1 + v[9]*s2 + v[14]*s3  + v[19]*s4 + v[24]*s5;
137   }
138 
139   ierr = VecRestoreArrayRead(bb,&b);CHKERRQ(ierr);
140   ierr = VecRestoreArray(xx,&x);CHKERRQ(ierr);
141   ierr = PetscLogFlops(2.0*25*(a->nz) - 5.0*A->cmap->n);CHKERRQ(ierr);
142   PetscFunctionReturn(0);
143 }
144