xref: /petsc/src/mat/impls/baij/seq/baijsolvnat6.c (revision d2fd7bfc6f0fd2e1d083decbb7cc7d77e16824f0)
1 #include <../src/mat/impls/baij/seq/baij.h>
2 #include <petsc/private/kernels/blockinvert.h>
3 
4 
5 PetscErrorCode MatSolve_SeqBAIJ_6_NaturalOrdering_inplace(Mat A,Vec bb,Vec xx)
6 {
7   Mat_SeqBAIJ       *a = (Mat_SeqBAIJ*)A->data;
8   PetscInt          i,nz,idx,idt,jdx;
9   PetscErrorCode    ierr;
10   const PetscInt    *diag = a->diag,*vi,n=a->mbs,*ai=a->i,*aj=a->j;
11   const MatScalar   *aa   =a->a,*v;
12   PetscScalar       *x,s1,s2,s3,s4,s5,s6,x1,x2,x3,x4,x5,x6;
13   const PetscScalar *b;
14 
15   PetscFunctionBegin;
16   ierr = VecGetArrayRead(bb,&b);CHKERRQ(ierr);
17   ierr = VecGetArray(xx,&x);CHKERRQ(ierr);
18   /* forward solve the lower triangular */
19   idx  = 0;
20   x[0] = b[idx];   x[1] = b[1+idx]; x[2] = b[2+idx];
21   x[3] = b[3+idx]; x[4] = b[4+idx]; x[5] = b[5+idx];
22   for (i=1; i<n; i++) {
23     v   =  aa + 36*ai[i];
24     vi  =  aj + ai[i];
25     nz  =  diag[i] - ai[i];
26     idx =  6*i;
27     s1  =  b[idx];   s2 = b[1+idx]; s3 = b[2+idx];
28     s4  =  b[3+idx]; s5 = b[4+idx]; s6 = b[5+idx];
29     while (nz--) {
30       jdx = 6*(*vi++);
31       x1  = x[jdx];   x2 = x[1+jdx]; x3 = x[2+jdx];
32       x4  = x[3+jdx]; x5 = x[4+jdx]; x6 = x[5+jdx];
33       s1 -= v[0]*x1 + v[6]*x2  + v[12]*x3 + v[18]*x4 + v[24]*x5 + v[30]*x6;
34       s2 -= v[1]*x1 + v[7]*x2  + v[13]*x3 + v[19]*x4 + v[25]*x5 + v[31]*x6;
35       s3 -= v[2]*x1 + v[8]*x2  + v[14]*x3 + v[20]*x4 + v[26]*x5 + v[32]*x6;
36       s4 -= v[3]*x1 + v[9]*x2  + v[15]*x3 + v[21]*x4 + v[27]*x5 + v[33]*x6;
37       s5 -= v[4]*x1 + v[10]*x2 + v[16]*x3 + v[22]*x4 + v[28]*x5 + v[34]*x6;
38       s6 -= v[5]*x1 + v[11]*x2 + v[17]*x3 + v[23]*x4 + v[29]*x5 + v[35]*x6;
39       v  += 36;
40     }
41     x[idx]   = s1;
42     x[1+idx] = s2;
43     x[2+idx] = s3;
44     x[3+idx] = s4;
45     x[4+idx] = s5;
46     x[5+idx] = s6;
47   }
48   /* backward solve the upper triangular */
49   for (i=n-1; i>=0; i--) {
50     v   = aa + 36*diag[i] + 36;
51     vi  = aj + diag[i] + 1;
52     nz  = ai[i+1] - diag[i] - 1;
53     idt = 6*i;
54     s1  = x[idt];   s2 = x[1+idt];
55     s3  = x[2+idt]; s4 = x[3+idt];
56     s5  = x[4+idt]; s6 = x[5+idt];
57     while (nz--) {
58       idx = 6*(*vi++);
59       x1  = x[idx];   x2 = x[1+idx]; x3 = x[2+idx];
60       x4  = x[3+idx]; x5 = x[4+idx]; x6 = x[5+idx];
61       s1 -= v[0]*x1 + v[6]*x2  + v[12]*x3 + v[18]*x4 + v[24]*x5 + v[30]*x6;
62       s2 -= v[1]*x1 + v[7]*x2  + v[13]*x3 + v[19]*x4 + v[25]*x5 + v[31]*x6;
63       s3 -= v[2]*x1 + v[8]*x2  + v[14]*x3 + v[20]*x4 + v[26]*x5 + v[32]*x6;
64       s4 -= v[3]*x1 + v[9]*x2  + v[15]*x3 + v[21]*x4 + v[27]*x5 + v[33]*x6;
65       s5 -= v[4]*x1 + v[10]*x2 + v[16]*x3 + v[22]*x4 + v[28]*x5 + v[34]*x6;
66       s6 -= v[5]*x1 + v[11]*x2 + v[17]*x3 + v[23]*x4 + v[29]*x5 + v[35]*x6;
67       v  += 36;
68     }
69     v        = aa + 36*diag[i];
70     x[idt]   = v[0]*s1 + v[6]*s2  + v[12]*s3 + v[18]*s4 + v[24]*s5 + v[30]*s6;
71     x[1+idt] = v[1]*s1 + v[7]*s2  + v[13]*s3 + v[19]*s4 + v[25]*s5 + v[31]*s6;
72     x[2+idt] = v[2]*s1 + v[8]*s2  + v[14]*s3 + v[20]*s4 + v[26]*s5 + v[32]*s6;
73     x[3+idt] = v[3]*s1 + v[9]*s2  + v[15]*s3 + v[21]*s4 + v[27]*s5 + v[33]*s6;
74     x[4+idt] = v[4]*s1 + v[10]*s2 + v[16]*s3 + v[22]*s4 + v[28]*s5 + v[34]*s6;
75     x[5+idt] = v[5]*s1 + v[11]*s2 + v[17]*s3 + v[23]*s4 + v[29]*s5 + v[35]*s6;
76   }
77 
78   ierr = VecRestoreArrayRead(bb,&b);CHKERRQ(ierr);
79   ierr = VecRestoreArray(xx,&x);CHKERRQ(ierr);
80   ierr = PetscLogFlops(2.0*36*(a->nz) - 6.0*A->cmap->n);CHKERRQ(ierr);
81   PetscFunctionReturn(0);
82 }
83 
84 PetscErrorCode MatSolve_SeqBAIJ_6_NaturalOrdering(Mat A,Vec bb,Vec xx)
85 {
86   Mat_SeqBAIJ       *a = (Mat_SeqBAIJ*)A->data;
87   const PetscInt    n  =a->mbs,*vi,*ai=a->i,*aj=a->j,*adiag=a->diag;
88   PetscErrorCode    ierr;
89   PetscInt          i,k,nz,idx,jdx,idt;
90   const PetscInt    bs = A->rmap->bs,bs2 = a->bs2;
91   const MatScalar   *aa=a->a,*v;
92   PetscScalar       *x;
93   const PetscScalar *b;
94   PetscScalar       s1,s2,s3,s4,s5,s6,x1,x2,x3,x4,x5,x6;
95 
96   PetscFunctionBegin;
97   ierr = VecGetArrayRead(bb,&b);CHKERRQ(ierr);
98   ierr = VecGetArray(xx,&x);CHKERRQ(ierr);
99   /* forward solve the lower triangular */
100   idx  = 0;
101   x[0] = b[idx]; x[1] = b[1+idx];x[2] = b[2+idx];x[3] = b[3+idx];
102   x[4] = b[4+idx];x[5] = b[5+idx];
103   for (i=1; i<n; i++) {
104     v   = aa + bs2*ai[i];
105     vi  = aj + ai[i];
106     nz  = ai[i+1] - ai[i];
107     idx = bs*i;
108     s1  = b[idx];s2 = b[1+idx];s3 = b[2+idx];s4 = b[3+idx];
109     s5  = b[4+idx];s6 = b[5+idx];
110     for (k=0; k<nz; k++) {
111       jdx = bs*vi[k];
112       x1  = x[jdx];x2 = x[1+jdx]; x3 =x[2+jdx];x4 =x[3+jdx];
113       x5  = x[4+jdx]; x6 = x[5+jdx];
114       s1 -= v[0]*x1 + v[6]*x2 + v[12]*x3 + v[18]*x4  + v[24]*x5 + v[30]*x6;
115       s2 -= v[1]*x1 + v[7]*x2 + v[13]*x3 + v[19]*x4  + v[25]*x5 + v[31]*x6;
116       s3 -= v[2]*x1 + v[8]*x2 + v[14]*x3 + v[20]*x4  + v[26]*x5 + v[32]*x6;
117       s4 -= v[3]*x1 + v[9]*x2 + v[15]*x3 + v[21]*x4  + v[27]*x5 + v[33]*x6;
118       s5 -= v[4]*x1 + v[10]*x2 + v[16]*x3 + v[22]*x4  + v[28]*x5 + v[34]*x6;
119       s6 -= v[5]*x1 + v[11]*x2 + v[17]*x3 + v[23]*x4  + v[29]*x5 + v[35]*x6;
120       v  +=  bs2;
121     }
122 
123     x[idx]   = s1;
124     x[1+idx] = s2;
125     x[2+idx] = s3;
126     x[3+idx] = s4;
127     x[4+idx] = s5;
128     x[5+idx] = s6;
129   }
130 
131   /* backward solve the upper triangular */
132   for (i=n-1; i>=0; i--) {
133     v   = aa + bs2*(adiag[i+1]+1);
134     vi  = aj + adiag[i+1]+1;
135     nz  = adiag[i] - adiag[i+1]-1;
136     idt = bs*i;
137     s1  = x[idt];  s2 = x[1+idt];s3 = x[2+idt];s4 = x[3+idt];
138     s5  = x[4+idt];s6 = x[5+idt];
139     for (k=0; k<nz; k++) {
140       idx = bs*vi[k];
141       x1  = x[idx];   x2 = x[1+idx]; x3 = x[2+idx];x4 = x[3+idx];
142       x5  = x[4+idx];x6 = x[5+idx];
143       s1 -= v[0]*x1 + v[6]*x2 + v[12]*x3 + v[18]*x4  + v[24]*x5 + v[30]*x6;
144       s2 -= v[1]*x1 + v[7]*x2 + v[13]*x3 + v[19]*x4  + v[25]*x5 + v[31]*x6;
145       s3 -= v[2]*x1 + v[8]*x2 + v[14]*x3 + v[20]*x4  + v[26]*x5 + v[32]*x6;
146       s4 -= v[3]*x1 + v[9]*x2 + v[15]*x3 + v[21]*x4  + v[27]*x5 + v[33]*x6;
147       s5 -= v[4]*x1 + v[10]*x2 + v[16]*x3 + v[22]*x4  + v[28]*x5 + v[34]*x6;
148       s6 -= v[5]*x1 + v[11]*x2 + v[17]*x3 + v[23]*x4  + v[29]*x5 + v[35]*x6;
149       v  +=  bs2;
150     }
151     /* x = inv_diagonal*x */
152     x[idt]   = v[0]*s1 + v[6]*s2 + v[12]*s3 + v[18]*s4 + v[24]*s5 + v[30]*s6;
153     x[1+idt] = v[1]*s1 + v[7]*s2 + v[13]*s3 + v[19]*s4 + v[25]*s5 + v[31]*s6;
154     x[2+idt] = v[2]*s1 + v[8]*s2 + v[14]*s3 + v[20]*s4 + v[26]*s5 + v[32]*s6;
155     x[3+idt] = v[3]*s1 + v[9]*s2 + v[15]*s3 + v[21]*s4 + v[27]*s5 + v[33]*s6;
156     x[4+idt] = v[4]*s1 + v[10]*s2 + v[16]*s3 + v[22]*s4 + v[28]*s5 + v[34]*s6;
157     x[5+idt] = v[5]*s1 + v[11]*s2 + v[17]*s3 + v[23]*s4 + v[29]*s5 + v[35]*s6;
158   }
159 
160   ierr = VecRestoreArrayRead(bb,&b);CHKERRQ(ierr);
161   ierr = VecRestoreArray(xx,&x);CHKERRQ(ierr);
162   ierr = PetscLogFlops(2.0*bs2*(a->nz) - bs*A->cmap->n);CHKERRQ(ierr);
163   PetscFunctionReturn(0);
164 }
165