xref: /petsc/src/mat/impls/baij/seq/baijsolvnat6.c (revision ccb4e88a40f0b86eaeca07ff64c64e4de2fae686)
1 #include <../src/mat/impls/baij/seq/baij.h>
2 #include <petsc/private/kernels/blockinvert.h>
3 
4 PetscErrorCode MatSolve_SeqBAIJ_6_NaturalOrdering_inplace(Mat A,Vec bb,Vec xx)
5 {
6   Mat_SeqBAIJ       *a = (Mat_SeqBAIJ*)A->data;
7   PetscInt          i,nz,idx,idt,jdx;
8   PetscErrorCode    ierr;
9   const PetscInt    *diag = a->diag,*vi,n=a->mbs,*ai=a->i,*aj=a->j;
10   const MatScalar   *aa   =a->a,*v;
11   PetscScalar       *x,s1,s2,s3,s4,s5,s6,x1,x2,x3,x4,x5,x6;
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];
20   x[3] = b[3+idx]; x[4] = b[4+idx]; x[5] = b[5+idx];
21   for (i=1; i<n; i++) {
22     v   =  aa + 36*ai[i];
23     vi  =  aj + ai[i];
24     nz  =  diag[i] - ai[i];
25     idx =  6*i;
26     s1  =  b[idx];   s2 = b[1+idx]; s3 = b[2+idx];
27     s4  =  b[3+idx]; s5 = b[4+idx]; s6 = b[5+idx];
28     while (nz--) {
29       jdx = 6*(*vi++);
30       x1  = x[jdx];   x2 = x[1+jdx]; x3 = x[2+jdx];
31       x4  = x[3+jdx]; x5 = x[4+jdx]; x6 = x[5+jdx];
32       s1 -= v[0]*x1 + v[6]*x2  + v[12]*x3 + v[18]*x4 + v[24]*x5 + v[30]*x6;
33       s2 -= v[1]*x1 + v[7]*x2  + v[13]*x3 + v[19]*x4 + v[25]*x5 + v[31]*x6;
34       s3 -= v[2]*x1 + v[8]*x2  + v[14]*x3 + v[20]*x4 + v[26]*x5 + v[32]*x6;
35       s4 -= v[3]*x1 + v[9]*x2  + v[15]*x3 + v[21]*x4 + v[27]*x5 + v[33]*x6;
36       s5 -= v[4]*x1 + v[10]*x2 + v[16]*x3 + v[22]*x4 + v[28]*x5 + v[34]*x6;
37       s6 -= v[5]*x1 + v[11]*x2 + v[17]*x3 + v[23]*x4 + v[29]*x5 + v[35]*x6;
38       v  += 36;
39     }
40     x[idx]   = s1;
41     x[1+idx] = s2;
42     x[2+idx] = s3;
43     x[3+idx] = s4;
44     x[4+idx] = s5;
45     x[5+idx] = s6;
46   }
47   /* backward solve the upper triangular */
48   for (i=n-1; i>=0; i--) {
49     v   = aa + 36*diag[i] + 36;
50     vi  = aj + diag[i] + 1;
51     nz  = ai[i+1] - diag[i] - 1;
52     idt = 6*i;
53     s1  = x[idt];   s2 = x[1+idt];
54     s3  = x[2+idt]; s4 = x[3+idt];
55     s5  = x[4+idt]; s6 = x[5+idt];
56     while (nz--) {
57       idx = 6*(*vi++);
58       x1  = x[idx];   x2 = x[1+idx]; x3 = x[2+idx];
59       x4  = x[3+idx]; x5 = x[4+idx]; x6 = x[5+idx];
60       s1 -= v[0]*x1 + v[6]*x2  + v[12]*x3 + v[18]*x4 + v[24]*x5 + v[30]*x6;
61       s2 -= v[1]*x1 + v[7]*x2  + v[13]*x3 + v[19]*x4 + v[25]*x5 + v[31]*x6;
62       s3 -= v[2]*x1 + v[8]*x2  + v[14]*x3 + v[20]*x4 + v[26]*x5 + v[32]*x6;
63       s4 -= v[3]*x1 + v[9]*x2  + v[15]*x3 + v[21]*x4 + v[27]*x5 + v[33]*x6;
64       s5 -= v[4]*x1 + v[10]*x2 + v[16]*x3 + v[22]*x4 + v[28]*x5 + v[34]*x6;
65       s6 -= v[5]*x1 + v[11]*x2 + v[17]*x3 + v[23]*x4 + v[29]*x5 + v[35]*x6;
66       v  += 36;
67     }
68     v        = aa + 36*diag[i];
69     x[idt]   = v[0]*s1 + v[6]*s2  + v[12]*s3 + v[18]*s4 + v[24]*s5 + v[30]*s6;
70     x[1+idt] = v[1]*s1 + v[7]*s2  + v[13]*s3 + v[19]*s4 + v[25]*s5 + v[31]*s6;
71     x[2+idt] = v[2]*s1 + v[8]*s2  + v[14]*s3 + v[20]*s4 + v[26]*s5 + v[32]*s6;
72     x[3+idt] = v[3]*s1 + v[9]*s2  + v[15]*s3 + v[21]*s4 + v[27]*s5 + v[33]*s6;
73     x[4+idt] = v[4]*s1 + v[10]*s2 + v[16]*s3 + v[22]*s4 + v[28]*s5 + v[34]*s6;
74     x[5+idt] = v[5]*s1 + v[11]*s2 + v[17]*s3 + v[23]*s4 + v[29]*s5 + v[35]*s6;
75   }
76 
77   ierr = VecRestoreArrayRead(bb,&b);CHKERRQ(ierr);
78   ierr = VecRestoreArray(xx,&x);CHKERRQ(ierr);
79   ierr = PetscLogFlops(2.0*36*(a->nz) - 6.0*A->cmap->n);CHKERRQ(ierr);
80   PetscFunctionReturn(0);
81 }
82 
83 PetscErrorCode MatSolve_SeqBAIJ_6_NaturalOrdering(Mat A,Vec bb,Vec xx)
84 {
85   Mat_SeqBAIJ       *a = (Mat_SeqBAIJ*)A->data;
86   const PetscInt    n  =a->mbs,*vi,*ai=a->i,*aj=a->j,*adiag=a->diag;
87   PetscErrorCode    ierr;
88   PetscInt          i,k,nz,idx,jdx,idt;
89   const PetscInt    bs = A->rmap->bs,bs2 = a->bs2;
90   const MatScalar   *aa=a->a,*v;
91   PetscScalar       *x;
92   const PetscScalar *b;
93   PetscScalar       s1,s2,s3,s4,s5,s6,x1,x2,x3,x4,x5,x6;
94 
95   PetscFunctionBegin;
96   ierr = VecGetArrayRead(bb,&b);CHKERRQ(ierr);
97   ierr = VecGetArray(xx,&x);CHKERRQ(ierr);
98   /* forward solve the lower triangular */
99   idx  = 0;
100   x[0] = b[idx]; x[1] = b[1+idx];x[2] = b[2+idx];x[3] = b[3+idx];
101   x[4] = b[4+idx];x[5] = b[5+idx];
102   for (i=1; i<n; i++) {
103     v   = aa + bs2*ai[i];
104     vi  = aj + ai[i];
105     nz  = ai[i+1] - ai[i];
106     idx = bs*i;
107     s1  = b[idx];s2 = b[1+idx];s3 = b[2+idx];s4 = b[3+idx];
108     s5  = b[4+idx];s6 = b[5+idx];
109     for (k=0; k<nz; k++) {
110       jdx = bs*vi[k];
111       x1  = x[jdx];x2 = x[1+jdx]; x3 =x[2+jdx];x4 =x[3+jdx];
112       x5  = x[4+jdx]; x6 = x[5+jdx];
113       s1 -= v[0]*x1 + v[6]*x2 + v[12]*x3 + v[18]*x4  + v[24]*x5 + v[30]*x6;
114       s2 -= v[1]*x1 + v[7]*x2 + v[13]*x3 + v[19]*x4  + v[25]*x5 + v[31]*x6;
115       s3 -= v[2]*x1 + v[8]*x2 + v[14]*x3 + v[20]*x4  + v[26]*x5 + v[32]*x6;
116       s4 -= v[3]*x1 + v[9]*x2 + v[15]*x3 + v[21]*x4  + v[27]*x5 + v[33]*x6;
117       s5 -= v[4]*x1 + v[10]*x2 + v[16]*x3 + v[22]*x4  + v[28]*x5 + v[34]*x6;
118       s6 -= v[5]*x1 + v[11]*x2 + v[17]*x3 + v[23]*x4  + v[29]*x5 + v[35]*x6;
119       v  +=  bs2;
120     }
121 
122     x[idx]   = s1;
123     x[1+idx] = s2;
124     x[2+idx] = s3;
125     x[3+idx] = s4;
126     x[4+idx] = s5;
127     x[5+idx] = s6;
128   }
129 
130   /* backward solve the upper triangular */
131   for (i=n-1; i>=0; i--) {
132     v   = aa + bs2*(adiag[i+1]+1);
133     vi  = aj + adiag[i+1]+1;
134     nz  = adiag[i] - adiag[i+1]-1;
135     idt = bs*i;
136     s1  = x[idt];  s2 = x[1+idt];s3 = x[2+idt];s4 = x[3+idt];
137     s5  = x[4+idt];s6 = x[5+idt];
138     for (k=0; k<nz; k++) {
139       idx = bs*vi[k];
140       x1  = x[idx];   x2 = x[1+idx]; x3 = x[2+idx];x4 = x[3+idx];
141       x5  = x[4+idx];x6 = x[5+idx];
142       s1 -= v[0]*x1 + v[6]*x2 + v[12]*x3 + v[18]*x4  + v[24]*x5 + v[30]*x6;
143       s2 -= v[1]*x1 + v[7]*x2 + v[13]*x3 + v[19]*x4  + v[25]*x5 + v[31]*x6;
144       s3 -= v[2]*x1 + v[8]*x2 + v[14]*x3 + v[20]*x4  + v[26]*x5 + v[32]*x6;
145       s4 -= v[3]*x1 + v[9]*x2 + v[15]*x3 + v[21]*x4  + v[27]*x5 + v[33]*x6;
146       s5 -= v[4]*x1 + v[10]*x2 + v[16]*x3 + v[22]*x4  + v[28]*x5 + v[34]*x6;
147       s6 -= v[5]*x1 + v[11]*x2 + v[17]*x3 + v[23]*x4  + v[29]*x5 + v[35]*x6;
148       v  +=  bs2;
149     }
150     /* x = inv_diagonal*x */
151     x[idt]   = v[0]*s1 + v[6]*s2 + v[12]*s3 + v[18]*s4 + v[24]*s5 + v[30]*s6;
152     x[1+idt] = v[1]*s1 + v[7]*s2 + v[13]*s3 + v[19]*s4 + v[25]*s5 + v[31]*s6;
153     x[2+idt] = v[2]*s1 + v[8]*s2 + v[14]*s3 + v[20]*s4 + v[26]*s5 + v[32]*s6;
154     x[3+idt] = v[3]*s1 + v[9]*s2 + v[15]*s3 + v[21]*s4 + v[27]*s5 + v[33]*s6;
155     x[4+idt] = v[4]*s1 + v[10]*s2 + v[16]*s3 + v[22]*s4 + v[28]*s5 + v[34]*s6;
156     x[5+idt] = v[5]*s1 + v[11]*s2 + v[17]*s3 + v[23]*s4 + v[29]*s5 + v[35]*s6;
157   }
158 
159   ierr = VecRestoreArrayRead(bb,&b);CHKERRQ(ierr);
160   ierr = VecRestoreArray(xx,&x);CHKERRQ(ierr);
161   ierr = PetscLogFlops(2.0*bs2*(a->nz) - bs*A->cmap->n);CHKERRQ(ierr);
162   PetscFunctionReturn(0);
163 }
164