xref: /petsc/src/mat/impls/baij/seq/baijsolvnat15.c (revision 6996bd1a6dda9216f11f3a1c5d2357ea301aa80d)
1 #include <../src/mat/impls/baij/seq/baij.h>
2 #include <petsc/private/kernels/blockinvert.h>
3 
4 /* bs = 15 for PFLOTRAN. Block operations are done by accessing all the columns   of the block at once */
5 
MatSolve_SeqBAIJ_15_NaturalOrdering_ver2(Mat A,Vec bb,Vec xx)6 PetscErrorCode MatSolve_SeqBAIJ_15_NaturalOrdering_ver2(Mat A, Vec bb, Vec xx)
7 {
8   Mat_SeqBAIJ       *a = (Mat_SeqBAIJ *)A->data;
9   const PetscInt     n = a->mbs, *ai = a->i, *aj = a->j, *adiag = a->diag, *vi, bs = A->rmap->bs, bs2 = a->bs2;
10   PetscInt           i, nz, idx, idt, m;
11   const MatScalar   *aa = a->a, *v;
12   PetscScalar        s1, s2, s3, s4, s5, s6, s7, s8, s9, s10, s11, s12, s13, s14, s15;
13   PetscScalar        x1, x2, x3, x4, x5, x6, x7, x8, x9, x10, x11, x12, x13, x14, x15;
14   PetscScalar       *x;
15   const PetscScalar *b;
16 
17   PetscFunctionBegin;
18   PetscCall(VecGetArrayRead(bb, &b));
19   PetscCall(VecGetArray(xx, &x));
20 
21   /* forward solve the lower triangular */
22   idx   = 0;
23   x[0]  = b[idx];
24   x[1]  = b[1 + idx];
25   x[2]  = b[2 + idx];
26   x[3]  = b[3 + idx];
27   x[4]  = b[4 + idx];
28   x[5]  = b[5 + idx];
29   x[6]  = b[6 + idx];
30   x[7]  = b[7 + idx];
31   x[8]  = b[8 + idx];
32   x[9]  = b[9 + idx];
33   x[10] = b[10 + idx];
34   x[11] = b[11 + idx];
35   x[12] = b[12 + idx];
36   x[13] = b[13 + idx];
37   x[14] = b[14 + idx];
38 
39   for (i = 1; i < n; i++) {
40     v   = aa + bs2 * ai[i];
41     vi  = aj + ai[i];
42     nz  = ai[i + 1] - ai[i];
43     idt = bs * i;
44     s1  = b[idt];
45     s2  = b[1 + idt];
46     s3  = b[2 + idt];
47     s4  = b[3 + idt];
48     s5  = b[4 + idt];
49     s6  = b[5 + idt];
50     s7  = b[6 + idt];
51     s8  = b[7 + idt];
52     s9  = b[8 + idt];
53     s10 = b[9 + idt];
54     s11 = b[10 + idt];
55     s12 = b[11 + idt];
56     s13 = b[12 + idt];
57     s14 = b[13 + idt];
58     s15 = b[14 + idt];
59     for (m = 0; m < nz; m++) {
60       idx = bs * vi[m];
61       x1  = x[idx];
62       x2  = x[1 + idx];
63       x3  = x[2 + idx];
64       x4  = x[3 + idx];
65       x5  = x[4 + idx];
66       x6  = x[5 + idx];
67       x7  = x[6 + idx];
68       x8  = x[7 + idx];
69       x9  = x[8 + idx];
70       x10 = x[9 + idx];
71       x11 = x[10 + idx];
72       x12 = x[11 + idx];
73       x13 = x[12 + idx];
74       x14 = x[13 + idx];
75       x15 = x[14 + idx];
76 
77       s1 -= v[0] * x1 + v[15] * x2 + v[30] * x3 + v[45] * x4 + v[60] * x5 + v[75] * x6 + v[90] * x7 + v[105] * x8 + v[120] * x9 + v[135] * x10 + v[150] * x11 + v[165] * x12 + v[180] * x13 + v[195] * x14 + v[210] * x15;
78       s2 -= v[1] * x1 + v[16] * x2 + v[31] * x3 + v[46] * x4 + v[61] * x5 + v[76] * x6 + v[91] * x7 + v[106] * x8 + v[121] * x9 + v[136] * x10 + v[151] * x11 + v[166] * x12 + v[181] * x13 + v[196] * x14 + v[211] * x15;
79       s3 -= v[2] * x1 + v[17] * x2 + v[32] * x3 + v[47] * x4 + v[62] * x5 + v[77] * x6 + v[92] * x7 + v[107] * x8 + v[122] * x9 + v[137] * x10 + v[152] * x11 + v[167] * x12 + v[182] * x13 + v[197] * x14 + v[212] * x15;
80       s4 -= v[3] * x1 + v[18] * x2 + v[33] * x3 + v[48] * x4 + v[63] * x5 + v[78] * x6 + v[93] * x7 + v[108] * x8 + v[123] * x9 + v[138] * x10 + v[153] * x11 + v[168] * x12 + v[183] * x13 + v[198] * x14 + v[213] * x15;
81       s5 -= v[4] * x1 + v[19] * x2 + v[34] * x3 + v[49] * x4 + v[64] * x5 + v[79] * x6 + v[94] * x7 + v[109] * x8 + v[124] * x9 + v[139] * x10 + v[154] * x11 + v[169] * x12 + v[184] * x13 + v[199] * x14 + v[214] * x15;
82       s6 -= v[5] * x1 + v[20] * x2 + v[35] * x3 + v[50] * x4 + v[65] * x5 + v[80] * x6 + v[95] * x7 + v[110] * x8 + v[125] * x9 + v[140] * x10 + v[155] * x11 + v[170] * x12 + v[185] * x13 + v[200] * x14 + v[215] * x15;
83       s7 -= v[6] * x1 + v[21] * x2 + v[36] * x3 + v[51] * x4 + v[66] * x5 + v[81] * x6 + v[96] * x7 + v[111] * x8 + v[126] * x9 + v[141] * x10 + v[156] * x11 + v[171] * x12 + v[186] * x13 + v[201] * x14 + v[216] * x15;
84       s8 -= v[7] * x1 + v[22] * x2 + v[37] * x3 + v[52] * x4 + v[67] * x5 + v[82] * x6 + v[97] * x7 + v[112] * x8 + v[127] * x9 + v[142] * x10 + v[157] * x11 + v[172] * x12 + v[187] * x13 + v[202] * x14 + v[217] * x15;
85       s9 -= v[8] * x1 + v[23] * x2 + v[38] * x3 + v[53] * x4 + v[68] * x5 + v[83] * x6 + v[98] * x7 + v[113] * x8 + v[128] * x9 + v[143] * x10 + v[158] * x11 + v[173] * x12 + v[188] * x13 + v[203] * x14 + v[218] * x15;
86       s10 -= v[9] * x1 + v[24] * x2 + v[39] * x3 + v[54] * x4 + v[69] * x5 + v[84] * x6 + v[99] * x7 + v[114] * x8 + v[129] * x9 + v[144] * x10 + v[159] * x11 + v[174] * x12 + v[189] * x13 + v[204] * x14 + v[219] * x15;
87       s11 -= v[10] * x1 + v[25] * x2 + v[40] * x3 + v[55] * x4 + v[70] * x5 + v[85] * x6 + v[100] * x7 + v[115] * x8 + v[130] * x9 + v[145] * x10 + v[160] * x11 + v[175] * x12 + v[190] * x13 + v[205] * x14 + v[220] * x15;
88       s12 -= v[11] * x1 + v[26] * x2 + v[41] * x3 + v[56] * x4 + v[71] * x5 + v[86] * x6 + v[101] * x7 + v[116] * x8 + v[131] * x9 + v[146] * x10 + v[161] * x11 + v[176] * x12 + v[191] * x13 + v[206] * x14 + v[221] * x15;
89       s13 -= v[12] * x1 + v[27] * x2 + v[42] * x3 + v[57] * x4 + v[72] * x5 + v[87] * x6 + v[102] * x7 + v[117] * x8 + v[132] * x9 + v[147] * x10 + v[162] * x11 + v[177] * x12 + v[192] * x13 + v[207] * x14 + v[222] * x15;
90       s14 -= v[13] * x1 + v[28] * x2 + v[43] * x3 + v[58] * x4 + v[73] * x5 + v[88] * x6 + v[103] * x7 + v[118] * x8 + v[133] * x9 + v[148] * x10 + v[163] * x11 + v[178] * x12 + v[193] * x13 + v[208] * x14 + v[223] * x15;
91       s15 -= v[14] * x1 + v[29] * x2 + v[44] * x3 + v[59] * x4 + v[74] * x5 + v[89] * x6 + v[104] * x7 + v[119] * x8 + v[134] * x9 + v[149] * x10 + v[164] * x11 + v[179] * x12 + v[194] * x13 + v[209] * x14 + v[224] * x15;
92 
93       v += bs2;
94     }
95     x[idt]      = s1;
96     x[1 + idt]  = s2;
97     x[2 + idt]  = s3;
98     x[3 + idt]  = s4;
99     x[4 + idt]  = s5;
100     x[5 + idt]  = s6;
101     x[6 + idt]  = s7;
102     x[7 + idt]  = s8;
103     x[8 + idt]  = s9;
104     x[9 + idt]  = s10;
105     x[10 + idt] = s11;
106     x[11 + idt] = s12;
107     x[12 + idt] = s13;
108     x[13 + idt] = s14;
109     x[14 + idt] = s15;
110   }
111   /* backward solve the upper triangular */
112   for (i = n - 1; i >= 0; i--) {
113     v   = aa + bs2 * (adiag[i + 1] + 1);
114     vi  = aj + adiag[i + 1] + 1;
115     nz  = adiag[i] - adiag[i + 1] - 1;
116     idt = bs * i;
117     s1  = x[idt];
118     s2  = x[1 + idt];
119     s3  = x[2 + idt];
120     s4  = x[3 + idt];
121     s5  = x[4 + idt];
122     s6  = x[5 + idt];
123     s7  = x[6 + idt];
124     s8  = x[7 + idt];
125     s9  = x[8 + idt];
126     s10 = x[9 + idt];
127     s11 = x[10 + idt];
128     s12 = x[11 + idt];
129     s13 = x[12 + idt];
130     s14 = x[13 + idt];
131     s15 = x[14 + idt];
132 
133     for (m = 0; m < nz; m++) {
134       idx = bs * vi[m];
135       x1  = x[idx];
136       x2  = x[1 + idx];
137       x3  = x[2 + idx];
138       x4  = x[3 + idx];
139       x5  = x[4 + idx];
140       x6  = x[5 + idx];
141       x7  = x[6 + idx];
142       x8  = x[7 + idx];
143       x9  = x[8 + idx];
144       x10 = x[9 + idx];
145       x11 = x[10 + idx];
146       x12 = x[11 + idx];
147       x13 = x[12 + idx];
148       x14 = x[13 + idx];
149       x15 = x[14 + idx];
150 
151       s1 -= v[0] * x1 + v[15] * x2 + v[30] * x3 + v[45] * x4 + v[60] * x5 + v[75] * x6 + v[90] * x7 + v[105] * x8 + v[120] * x9 + v[135] * x10 + v[150] * x11 + v[165] * x12 + v[180] * x13 + v[195] * x14 + v[210] * x15;
152       s2 -= v[1] * x1 + v[16] * x2 + v[31] * x3 + v[46] * x4 + v[61] * x5 + v[76] * x6 + v[91] * x7 + v[106] * x8 + v[121] * x9 + v[136] * x10 + v[151] * x11 + v[166] * x12 + v[181] * x13 + v[196] * x14 + v[211] * x15;
153       s3 -= v[2] * x1 + v[17] * x2 + v[32] * x3 + v[47] * x4 + v[62] * x5 + v[77] * x6 + v[92] * x7 + v[107] * x8 + v[122] * x9 + v[137] * x10 + v[152] * x11 + v[167] * x12 + v[182] * x13 + v[197] * x14 + v[212] * x15;
154       s4 -= v[3] * x1 + v[18] * x2 + v[33] * x3 + v[48] * x4 + v[63] * x5 + v[78] * x6 + v[93] * x7 + v[108] * x8 + v[123] * x9 + v[138] * x10 + v[153] * x11 + v[168] * x12 + v[183] * x13 + v[198] * x14 + v[213] * x15;
155       s5 -= v[4] * x1 + v[19] * x2 + v[34] * x3 + v[49] * x4 + v[64] * x5 + v[79] * x6 + v[94] * x7 + v[109] * x8 + v[124] * x9 + v[139] * x10 + v[154] * x11 + v[169] * x12 + v[184] * x13 + v[199] * x14 + v[214] * x15;
156       s6 -= v[5] * x1 + v[20] * x2 + v[35] * x3 + v[50] * x4 + v[65] * x5 + v[80] * x6 + v[95] * x7 + v[110] * x8 + v[125] * x9 + v[140] * x10 + v[155] * x11 + v[170] * x12 + v[185] * x13 + v[200] * x14 + v[215] * x15;
157       s7 -= v[6] * x1 + v[21] * x2 + v[36] * x3 + v[51] * x4 + v[66] * x5 + v[81] * x6 + v[96] * x7 + v[111] * x8 + v[126] * x9 + v[141] * x10 + v[156] * x11 + v[171] * x12 + v[186] * x13 + v[201] * x14 + v[216] * x15;
158       s8 -= v[7] * x1 + v[22] * x2 + v[37] * x3 + v[52] * x4 + v[67] * x5 + v[82] * x6 + v[97] * x7 + v[112] * x8 + v[127] * x9 + v[142] * x10 + v[157] * x11 + v[172] * x12 + v[187] * x13 + v[202] * x14 + v[217] * x15;
159       s9 -= v[8] * x1 + v[23] * x2 + v[38] * x3 + v[53] * x4 + v[68] * x5 + v[83] * x6 + v[98] * x7 + v[113] * x8 + v[128] * x9 + v[143] * x10 + v[158] * x11 + v[173] * x12 + v[188] * x13 + v[203] * x14 + v[218] * x15;
160       s10 -= v[9] * x1 + v[24] * x2 + v[39] * x3 + v[54] * x4 + v[69] * x5 + v[84] * x6 + v[99] * x7 + v[114] * x8 + v[129] * x9 + v[144] * x10 + v[159] * x11 + v[174] * x12 + v[189] * x13 + v[204] * x14 + v[219] * x15;
161       s11 -= v[10] * x1 + v[25] * x2 + v[40] * x3 + v[55] * x4 + v[70] * x5 + v[85] * x6 + v[100] * x7 + v[115] * x8 + v[130] * x9 + v[145] * x10 + v[160] * x11 + v[175] * x12 + v[190] * x13 + v[205] * x14 + v[220] * x15;
162       s12 -= v[11] * x1 + v[26] * x2 + v[41] * x3 + v[56] * x4 + v[71] * x5 + v[86] * x6 + v[101] * x7 + v[116] * x8 + v[131] * x9 + v[146] * x10 + v[161] * x11 + v[176] * x12 + v[191] * x13 + v[206] * x14 + v[221] * x15;
163       s13 -= v[12] * x1 + v[27] * x2 + v[42] * x3 + v[57] * x4 + v[72] * x5 + v[87] * x6 + v[102] * x7 + v[117] * x8 + v[132] * x9 + v[147] * x10 + v[162] * x11 + v[177] * x12 + v[192] * x13 + v[207] * x14 + v[222] * x15;
164       s14 -= v[13] * x1 + v[28] * x2 + v[43] * x3 + v[58] * x4 + v[73] * x5 + v[88] * x6 + v[103] * x7 + v[118] * x8 + v[133] * x9 + v[148] * x10 + v[163] * x11 + v[178] * x12 + v[193] * x13 + v[208] * x14 + v[223] * x15;
165       s15 -= v[14] * x1 + v[29] * x2 + v[44] * x3 + v[59] * x4 + v[74] * x5 + v[89] * x6 + v[104] * x7 + v[119] * x8 + v[134] * x9 + v[149] * x10 + v[164] * x11 + v[179] * x12 + v[194] * x13 + v[209] * x14 + v[224] * x15;
166 
167       v += bs2;
168     }
169 
170     x[idt]      = v[0] * s1 + v[15] * s2 + v[30] * s3 + v[45] * s4 + v[60] * s5 + v[75] * s6 + v[90] * s7 + v[105] * s8 + v[120] * s9 + v[135] * s10 + v[150] * s11 + v[165] * s12 + v[180] * s13 + v[195] * s14 + v[210] * s15;
171     x[1 + idt]  = v[1] * s1 + v[16] * s2 + v[31] * s3 + v[46] * s4 + v[61] * s5 + v[76] * s6 + v[91] * s7 + v[106] * s8 + v[121] * s9 + v[136] * s10 + v[151] * s11 + v[166] * s12 + v[181] * s13 + v[196] * s14 + v[211] * s15;
172     x[2 + idt]  = v[2] * s1 + v[17] * s2 + v[32] * s3 + v[47] * s4 + v[62] * s5 + v[77] * s6 + v[92] * s7 + v[107] * s8 + v[122] * s9 + v[137] * s10 + v[152] * s11 + v[167] * s12 + v[182] * s13 + v[197] * s14 + v[212] * s15;
173     x[3 + idt]  = v[3] * s1 + v[18] * s2 + v[33] * s3 + v[48] * s4 + v[63] * s5 + v[78] * s6 + v[93] * s7 + v[108] * s8 + v[123] * s9 + v[138] * s10 + v[153] * s11 + v[168] * s12 + v[183] * s13 + v[198] * s14 + v[213] * s15;
174     x[4 + idt]  = v[4] * s1 + v[19] * s2 + v[34] * s3 + v[49] * s4 + v[64] * s5 + v[79] * s6 + v[94] * s7 + v[109] * s8 + v[124] * s9 + v[139] * s10 + v[154] * s11 + v[169] * s12 + v[184] * s13 + v[199] * s14 + v[214] * s15;
175     x[5 + idt]  = v[5] * s1 + v[20] * s2 + v[35] * s3 + v[50] * s4 + v[65] * s5 + v[80] * s6 + v[95] * s7 + v[110] * s8 + v[125] * s9 + v[140] * s10 + v[155] * s11 + v[170] * s12 + v[185] * s13 + v[200] * s14 + v[215] * s15;
176     x[6 + idt]  = v[6] * s1 + v[21] * s2 + v[36] * s3 + v[51] * s4 + v[66] * s5 + v[81] * s6 + v[96] * s7 + v[111] * s8 + v[126] * s9 + v[141] * s10 + v[156] * s11 + v[171] * s12 + v[186] * s13 + v[201] * s14 + v[216] * s15;
177     x[7 + idt]  = v[7] * s1 + v[22] * s2 + v[37] * s3 + v[52] * s4 + v[67] * s5 + v[82] * s6 + v[97] * s7 + v[112] * s8 + v[127] * s9 + v[142] * s10 + v[157] * s11 + v[172] * s12 + v[187] * s13 + v[202] * s14 + v[217] * s15;
178     x[8 + idt]  = v[8] * s1 + v[23] * s2 + v[38] * s3 + v[53] * s4 + v[68] * s5 + v[83] * s6 + v[98] * s7 + v[113] * s8 + v[128] * s9 + v[143] * s10 + v[158] * s11 + v[173] * s12 + v[188] * s13 + v[203] * s14 + v[218] * s15;
179     x[9 + idt]  = v[9] * s1 + v[24] * s2 + v[39] * s3 + v[54] * s4 + v[69] * s5 + v[84] * s6 + v[99] * s7 + v[114] * s8 + v[129] * s9 + v[144] * s10 + v[159] * s11 + v[174] * s12 + v[189] * s13 + v[204] * s14 + v[219] * s15;
180     x[10 + idt] = v[10] * s1 + v[25] * s2 + v[40] * s3 + v[55] * s4 + v[70] * s5 + v[85] * s6 + v[100] * s7 + v[115] * s8 + v[130] * s9 + v[145] * s10 + v[160] * s11 + v[175] * s12 + v[190] * s13 + v[205] * s14 + v[220] * s15;
181     x[11 + idt] = v[11] * s1 + v[26] * s2 + v[41] * s3 + v[56] * s4 + v[71] * s5 + v[86] * s6 + v[101] * s7 + v[116] * s8 + v[131] * s9 + v[146] * s10 + v[161] * s11 + v[176] * s12 + v[191] * s13 + v[206] * s14 + v[221] * s15;
182     x[12 + idt] = v[12] * s1 + v[27] * s2 + v[42] * s3 + v[57] * s4 + v[72] * s5 + v[87] * s6 + v[102] * s7 + v[117] * s8 + v[132] * s9 + v[147] * s10 + v[162] * s11 + v[177] * s12 + v[192] * s13 + v[207] * s14 + v[222] * s15;
183     x[13 + idt] = v[13] * s1 + v[28] * s2 + v[43] * s3 + v[58] * s4 + v[73] * s5 + v[88] * s6 + v[103] * s7 + v[118] * s8 + v[133] * s9 + v[148] * s10 + v[163] * s11 + v[178] * s12 + v[193] * s13 + v[208] * s14 + v[223] * s15;
184     x[14 + idt] = v[14] * s1 + v[29] * s2 + v[44] * s3 + v[59] * s4 + v[74] * s5 + v[89] * s6 + v[104] * s7 + v[119] * s8 + v[134] * s9 + v[149] * s10 + v[164] * s11 + v[179] * s12 + v[194] * s13 + v[209] * s14 + v[224] * s15;
185   }
186 
187   PetscCall(VecRestoreArrayRead(bb, &b));
188   PetscCall(VecRestoreArray(xx, &x));
189   PetscCall(PetscLogFlops(2.0 * bs2 * (a->nz) - bs * A->cmap->n));
190   PetscFunctionReturn(PETSC_SUCCESS);
191 }
192 
193 /* bs = 15 for PFLOTRAN. Block operations are done by accessing one column at a time */
194 /* Default MatSolve for block size 15 */
195 
MatSolve_SeqBAIJ_15_NaturalOrdering_ver1(Mat A,Vec bb,Vec xx)196 PetscErrorCode MatSolve_SeqBAIJ_15_NaturalOrdering_ver1(Mat A, Vec bb, Vec xx)
197 {
198   Mat_SeqBAIJ       *a = (Mat_SeqBAIJ *)A->data;
199   const PetscInt     n = a->mbs, *ai = a->i, *aj = a->j, *adiag = a->diag, *vi, bs = A->rmap->bs, bs2 = a->bs2;
200   PetscInt           i, k, nz, idx, idt, m;
201   const MatScalar   *aa = a->a, *v;
202   PetscScalar        s[15];
203   PetscScalar       *x, xv;
204   const PetscScalar *b;
205 
206   PetscFunctionBegin;
207   PetscCall(VecGetArrayRead(bb, &b));
208   PetscCall(VecGetArray(xx, &x));
209 
210   /* forward solve the lower triangular */
211   for (i = 0; i < n; i++) {
212     v           = aa + bs2 * ai[i];
213     vi          = aj + ai[i];
214     nz          = ai[i + 1] - ai[i];
215     idt         = bs * i;
216     x[idt]      = b[idt];
217     x[1 + idt]  = b[1 + idt];
218     x[2 + idt]  = b[2 + idt];
219     x[3 + idt]  = b[3 + idt];
220     x[4 + idt]  = b[4 + idt];
221     x[5 + idt]  = b[5 + idt];
222     x[6 + idt]  = b[6 + idt];
223     x[7 + idt]  = b[7 + idt];
224     x[8 + idt]  = b[8 + idt];
225     x[9 + idt]  = b[9 + idt];
226     x[10 + idt] = b[10 + idt];
227     x[11 + idt] = b[11 + idt];
228     x[12 + idt] = b[12 + idt];
229     x[13 + idt] = b[13 + idt];
230     x[14 + idt] = b[14 + idt];
231     for (m = 0; m < nz; m++) {
232       idx = bs * vi[m];
233       for (k = 0; k < 15; k++) {
234         xv = x[k + idx];
235         x[idt] -= v[0] * xv;
236         x[1 + idt] -= v[1] * xv;
237         x[2 + idt] -= v[2] * xv;
238         x[3 + idt] -= v[3] * xv;
239         x[4 + idt] -= v[4] * xv;
240         x[5 + idt] -= v[5] * xv;
241         x[6 + idt] -= v[6] * xv;
242         x[7 + idt] -= v[7] * xv;
243         x[8 + idt] -= v[8] * xv;
244         x[9 + idt] -= v[9] * xv;
245         x[10 + idt] -= v[10] * xv;
246         x[11 + idt] -= v[11] * xv;
247         x[12 + idt] -= v[12] * xv;
248         x[13 + idt] -= v[13] * xv;
249         x[14 + idt] -= v[14] * xv;
250         v += 15;
251       }
252     }
253   }
254   /* backward solve the upper triangular */
255   for (i = n - 1; i >= 0; i--) {
256     v     = aa + bs2 * (adiag[i + 1] + 1);
257     vi    = aj + adiag[i + 1] + 1;
258     nz    = adiag[i] - adiag[i + 1] - 1;
259     idt   = bs * i;
260     s[0]  = x[idt];
261     s[1]  = x[1 + idt];
262     s[2]  = x[2 + idt];
263     s[3]  = x[3 + idt];
264     s[4]  = x[4 + idt];
265     s[5]  = x[5 + idt];
266     s[6]  = x[6 + idt];
267     s[7]  = x[7 + idt];
268     s[8]  = x[8 + idt];
269     s[9]  = x[9 + idt];
270     s[10] = x[10 + idt];
271     s[11] = x[11 + idt];
272     s[12] = x[12 + idt];
273     s[13] = x[13 + idt];
274     s[14] = x[14 + idt];
275 
276     for (m = 0; m < nz; m++) {
277       idx = bs * vi[m];
278       for (k = 0; k < 15; k++) {
279         xv = x[k + idx];
280         s[0] -= v[0] * xv;
281         s[1] -= v[1] * xv;
282         s[2] -= v[2] * xv;
283         s[3] -= v[3] * xv;
284         s[4] -= v[4] * xv;
285         s[5] -= v[5] * xv;
286         s[6] -= v[6] * xv;
287         s[7] -= v[7] * xv;
288         s[8] -= v[8] * xv;
289         s[9] -= v[9] * xv;
290         s[10] -= v[10] * xv;
291         s[11] -= v[11] * xv;
292         s[12] -= v[12] * xv;
293         s[13] -= v[13] * xv;
294         s[14] -= v[14] * xv;
295         v += 15;
296       }
297     }
298     PetscCall(PetscArrayzero(x + idt, bs));
299     for (k = 0; k < 15; k++) {
300       x[idt] += v[0] * s[k];
301       x[1 + idt] += v[1] * s[k];
302       x[2 + idt] += v[2] * s[k];
303       x[3 + idt] += v[3] * s[k];
304       x[4 + idt] += v[4] * s[k];
305       x[5 + idt] += v[5] * s[k];
306       x[6 + idt] += v[6] * s[k];
307       x[7 + idt] += v[7] * s[k];
308       x[8 + idt] += v[8] * s[k];
309       x[9 + idt] += v[9] * s[k];
310       x[10 + idt] += v[10] * s[k];
311       x[11 + idt] += v[11] * s[k];
312       x[12 + idt] += v[12] * s[k];
313       x[13 + idt] += v[13] * s[k];
314       x[14 + idt] += v[14] * s[k];
315       v += 15;
316     }
317   }
318   PetscCall(VecRestoreArrayRead(bb, &b));
319   PetscCall(VecRestoreArray(xx, &x));
320   PetscCall(PetscLogFlops(2.0 * bs2 * (a->nz) - bs * A->cmap->n));
321   PetscFunctionReturn(PETSC_SUCCESS);
322 }
323