xref: /petsc/src/mat/impls/baij/seq/baijfact5.c (revision 58d68138c660dfb4e9f5b03334792cd4f2ffd7cc)
1 
2 /*
3     Factorization code for BAIJ format.
4 */
5 #include <../src/mat/impls/baij/seq/baij.h>
6 #include <petsc/private/kernels/blockinvert.h>
7 /*
8       Version for when blocks are 7 by 7
9 */
10 PetscErrorCode MatLUFactorNumeric_SeqBAIJ_7_inplace(Mat C, Mat A, const MatFactorInfo *info) {
11   Mat_SeqBAIJ    *a = (Mat_SeqBAIJ *)A->data, *b = (Mat_SeqBAIJ *)C->data;
12   IS              isrow = b->row, isicol = b->icol;
13   const PetscInt *r, *ic, *bi = b->i, *bj = b->j, *ajtmp, *diag_offset = b->diag, *ai = a->i, *aj = a->j, *pj, *ajtmpold;
14   PetscInt        i, j, n = a->mbs, nz, row, idx;
15   MatScalar      *pv, *v, *rtmp, *pc, *w, *x;
16   MatScalar       p1, p2, p3, p4, m1, m2, m3, m4, m5, m6, m7, m8, m9, x1, x2, x3, x4;
17   MatScalar       p5, p6, p7, p8, p9, x5, x6, x7, x8, x9, x10, x11, x12, x13, x14, x15, x16;
18   MatScalar       x17, x18, x19, x20, x21, x22, x23, x24, x25, p10, p11, p12, p13, p14;
19   MatScalar       p15, p16, p17, p18, p19, p20, p21, p22, p23, p24, p25, m10, m11, m12;
20   MatScalar       m13, m14, m15, m16, m17, m18, m19, m20, m21, m22, m23, m24, m25;
21   MatScalar       p26, p27, p28, p29, p30, p31, p32, p33, p34, p35, p36;
22   MatScalar       p37, p38, p39, p40, p41, p42, p43, p44, p45, p46, p47, p48, p49;
23   MatScalar       x26, x27, x28, x29, x30, x31, x32, x33, x34, x35, x36;
24   MatScalar       x37, x38, x39, x40, x41, x42, x43, x44, x45, x46, x47, x48, x49;
25   MatScalar       m26, m27, m28, m29, m30, m31, m32, m33, m34, m35, m36;
26   MatScalar       m37, m38, m39, m40, m41, m42, m43, m44, m45, m46, m47, m48, m49;
27   MatScalar      *ba = b->a, *aa = a->a;
28   PetscReal       shift = info->shiftamount;
29   PetscBool       allowzeropivot, zeropivotdetected;
30 
31   PetscFunctionBegin;
32   allowzeropivot = PetscNot(A->erroriffailure);
33   PetscCall(ISGetIndices(isrow, &r));
34   PetscCall(ISGetIndices(isicol, &ic));
35   PetscCall(PetscMalloc1(49 * (n + 1), &rtmp));
36 
37   for (i = 0; i < n; i++) {
38     nz    = bi[i + 1] - bi[i];
39     ajtmp = bj + bi[i];
40     for (j = 0; j < nz; j++) {
41       x    = rtmp + 49 * ajtmp[j];
42       x[0] = x[1] = x[2] = x[3] = x[4] = x[5] = x[6] = x[7] = x[8] = x[9] = 0.0;
43       x[10] = x[11] = x[12] = x[13] = x[14] = x[15] = x[16] = x[17] = 0.0;
44       x[18] = x[19] = x[20] = x[21] = x[22] = x[23] = x[24] = x[25] = 0.0;
45       x[26] = x[27] = x[28] = x[29] = x[30] = x[31] = x[32] = x[33] = 0.0;
46       x[34] = x[35] = x[36] = x[37] = x[38] = x[39] = x[40] = x[41] = 0.0;
47       x[42] = x[43] = x[44] = x[45] = x[46] = x[47] = x[48] = 0.0;
48     }
49     /* load in initial (unfactored row) */
50     idx      = r[i];
51     nz       = ai[idx + 1] - ai[idx];
52     ajtmpold = aj + ai[idx];
53     v        = aa + 49 * ai[idx];
54     for (j = 0; j < nz; j++) {
55       x     = rtmp + 49 * ic[ajtmpold[j]];
56       x[0]  = v[0];
57       x[1]  = v[1];
58       x[2]  = v[2];
59       x[3]  = v[3];
60       x[4]  = v[4];
61       x[5]  = v[5];
62       x[6]  = v[6];
63       x[7]  = v[7];
64       x[8]  = v[8];
65       x[9]  = v[9];
66       x[10] = v[10];
67       x[11] = v[11];
68       x[12] = v[12];
69       x[13] = v[13];
70       x[14] = v[14];
71       x[15] = v[15];
72       x[16] = v[16];
73       x[17] = v[17];
74       x[18] = v[18];
75       x[19] = v[19];
76       x[20] = v[20];
77       x[21] = v[21];
78       x[22] = v[22];
79       x[23] = v[23];
80       x[24] = v[24];
81       x[25] = v[25];
82       x[26] = v[26];
83       x[27] = v[27];
84       x[28] = v[28];
85       x[29] = v[29];
86       x[30] = v[30];
87       x[31] = v[31];
88       x[32] = v[32];
89       x[33] = v[33];
90       x[34] = v[34];
91       x[35] = v[35];
92       x[36] = v[36];
93       x[37] = v[37];
94       x[38] = v[38];
95       x[39] = v[39];
96       x[40] = v[40];
97       x[41] = v[41];
98       x[42] = v[42];
99       x[43] = v[43];
100       x[44] = v[44];
101       x[45] = v[45];
102       x[46] = v[46];
103       x[47] = v[47];
104       x[48] = v[48];
105       v += 49;
106     }
107     row = *ajtmp++;
108     while (row < i) {
109       pc  = rtmp + 49 * row;
110       p1  = pc[0];
111       p2  = pc[1];
112       p3  = pc[2];
113       p4  = pc[3];
114       p5  = pc[4];
115       p6  = pc[5];
116       p7  = pc[6];
117       p8  = pc[7];
118       p9  = pc[8];
119       p10 = pc[9];
120       p11 = pc[10];
121       p12 = pc[11];
122       p13 = pc[12];
123       p14 = pc[13];
124       p15 = pc[14];
125       p16 = pc[15];
126       p17 = pc[16];
127       p18 = pc[17];
128       p19 = pc[18];
129       p20 = pc[19];
130       p21 = pc[20];
131       p22 = pc[21];
132       p23 = pc[22];
133       p24 = pc[23];
134       p25 = pc[24];
135       p26 = pc[25];
136       p27 = pc[26];
137       p28 = pc[27];
138       p29 = pc[28];
139       p30 = pc[29];
140       p31 = pc[30];
141       p32 = pc[31];
142       p33 = pc[32];
143       p34 = pc[33];
144       p35 = pc[34];
145       p36 = pc[35];
146       p37 = pc[36];
147       p38 = pc[37];
148       p39 = pc[38];
149       p40 = pc[39];
150       p41 = pc[40];
151       p42 = pc[41];
152       p43 = pc[42];
153       p44 = pc[43];
154       p45 = pc[44];
155       p46 = pc[45];
156       p47 = pc[46];
157       p48 = pc[47];
158       p49 = pc[48];
159       if (p1 != 0.0 || p2 != 0.0 || p3 != 0.0 || p4 != 0.0 || p5 != 0.0 || p6 != 0.0 || p7 != 0.0 || p8 != 0.0 || p9 != 0.0 || p10 != 0.0 || p11 != 0.0 || p12 != 0.0 || p13 != 0.0 || p14 != 0.0 || p15 != 0.0 || p16 != 0.0 || p17 != 0.0 || p18 != 0.0 || p19 != 0.0 || p20 != 0.0 || p21 != 0.0 || p22 != 0.0 || p23 != 0.0 || p24 != 0.0 || p25 != 0.0 || p26 != 0.0 || p27 != 0.0 || p28 != 0.0 || p29 != 0.0 || p30 != 0.0 || p31 != 0.0 || p32 != 0.0 || p33 != 0.0 || p34 != 0.0 || p35 != 0.0 || p36 != 0.0 || p37 != 0.0 || p38 != 0.0 || p39 != 0.0 || p40 != 0.0 || p41 != 0.0 || p42 != 0.0 || p43 != 0.0 || p44 != 0.0 || p45 != 0.0 || p46 != 0.0 || p47 != 0.0 || p48 != 0.0 || p49 != 0.0) {
160         pv    = ba + 49 * diag_offset[row];
161         pj    = bj + diag_offset[row] + 1;
162         x1    = pv[0];
163         x2    = pv[1];
164         x3    = pv[2];
165         x4    = pv[3];
166         x5    = pv[4];
167         x6    = pv[5];
168         x7    = pv[6];
169         x8    = pv[7];
170         x9    = pv[8];
171         x10   = pv[9];
172         x11   = pv[10];
173         x12   = pv[11];
174         x13   = pv[12];
175         x14   = pv[13];
176         x15   = pv[14];
177         x16   = pv[15];
178         x17   = pv[16];
179         x18   = pv[17];
180         x19   = pv[18];
181         x20   = pv[19];
182         x21   = pv[20];
183         x22   = pv[21];
184         x23   = pv[22];
185         x24   = pv[23];
186         x25   = pv[24];
187         x26   = pv[25];
188         x27   = pv[26];
189         x28   = pv[27];
190         x29   = pv[28];
191         x30   = pv[29];
192         x31   = pv[30];
193         x32   = pv[31];
194         x33   = pv[32];
195         x34   = pv[33];
196         x35   = pv[34];
197         x36   = pv[35];
198         x37   = pv[36];
199         x38   = pv[37];
200         x39   = pv[38];
201         x40   = pv[39];
202         x41   = pv[40];
203         x42   = pv[41];
204         x43   = pv[42];
205         x44   = pv[43];
206         x45   = pv[44];
207         x46   = pv[45];
208         x47   = pv[46];
209         x48   = pv[47];
210         x49   = pv[48];
211         pc[0] = m1 = p1 * x1 + p8 * x2 + p15 * x3 + p22 * x4 + p29 * x5 + p36 * x6 + p43 * x7;
212         pc[1] = m2 = p2 * x1 + p9 * x2 + p16 * x3 + p23 * x4 + p30 * x5 + p37 * x6 + p44 * x7;
213         pc[2] = m3 = p3 * x1 + p10 * x2 + p17 * x3 + p24 * x4 + p31 * x5 + p38 * x6 + p45 * x7;
214         pc[3] = m4 = p4 * x1 + p11 * x2 + p18 * x3 + p25 * x4 + p32 * x5 + p39 * x6 + p46 * x7;
215         pc[4] = m5 = p5 * x1 + p12 * x2 + p19 * x3 + p26 * x4 + p33 * x5 + p40 * x6 + p47 * x7;
216         pc[5] = m6 = p6 * x1 + p13 * x2 + p20 * x3 + p27 * x4 + p34 * x5 + p41 * x6 + p48 * x7;
217         pc[6] = m7 = p7 * x1 + p14 * x2 + p21 * x3 + p28 * x4 + p35 * x5 + p42 * x6 + p49 * x7;
218 
219         pc[7] = m8 = p1 * x8 + p8 * x9 + p15 * x10 + p22 * x11 + p29 * x12 + p36 * x13 + p43 * x14;
220         pc[8] = m9 = p2 * x8 + p9 * x9 + p16 * x10 + p23 * x11 + p30 * x12 + p37 * x13 + p44 * x14;
221         pc[9] = m10 = p3 * x8 + p10 * x9 + p17 * x10 + p24 * x11 + p31 * x12 + p38 * x13 + p45 * x14;
222         pc[10] = m11 = p4 * x8 + p11 * x9 + p18 * x10 + p25 * x11 + p32 * x12 + p39 * x13 + p46 * x14;
223         pc[11] = m12 = p5 * x8 + p12 * x9 + p19 * x10 + p26 * x11 + p33 * x12 + p40 * x13 + p47 * x14;
224         pc[12] = m13 = p6 * x8 + p13 * x9 + p20 * x10 + p27 * x11 + p34 * x12 + p41 * x13 + p48 * x14;
225         pc[13] = m14 = p7 * x8 + p14 * x9 + p21 * x10 + p28 * x11 + p35 * x12 + p42 * x13 + p49 * x14;
226 
227         pc[14] = m15 = p1 * x15 + p8 * x16 + p15 * x17 + p22 * x18 + p29 * x19 + p36 * x20 + p43 * x21;
228         pc[15] = m16 = p2 * x15 + p9 * x16 + p16 * x17 + p23 * x18 + p30 * x19 + p37 * x20 + p44 * x21;
229         pc[16] = m17 = p3 * x15 + p10 * x16 + p17 * x17 + p24 * x18 + p31 * x19 + p38 * x20 + p45 * x21;
230         pc[17] = m18 = p4 * x15 + p11 * x16 + p18 * x17 + p25 * x18 + p32 * x19 + p39 * x20 + p46 * x21;
231         pc[18] = m19 = p5 * x15 + p12 * x16 + p19 * x17 + p26 * x18 + p33 * x19 + p40 * x20 + p47 * x21;
232         pc[19] = m20 = p6 * x15 + p13 * x16 + p20 * x17 + p27 * x18 + p34 * x19 + p41 * x20 + p48 * x21;
233         pc[20] = m21 = p7 * x15 + p14 * x16 + p21 * x17 + p28 * x18 + p35 * x19 + p42 * x20 + p49 * x21;
234 
235         pc[21] = m22 = p1 * x22 + p8 * x23 + p15 * x24 + p22 * x25 + p29 * x26 + p36 * x27 + p43 * x28;
236         pc[22] = m23 = p2 * x22 + p9 * x23 + p16 * x24 + p23 * x25 + p30 * x26 + p37 * x27 + p44 * x28;
237         pc[23] = m24 = p3 * x22 + p10 * x23 + p17 * x24 + p24 * x25 + p31 * x26 + p38 * x27 + p45 * x28;
238         pc[24] = m25 = p4 * x22 + p11 * x23 + p18 * x24 + p25 * x25 + p32 * x26 + p39 * x27 + p46 * x28;
239         pc[25] = m26 = p5 * x22 + p12 * x23 + p19 * x24 + p26 * x25 + p33 * x26 + p40 * x27 + p47 * x28;
240         pc[26] = m27 = p6 * x22 + p13 * x23 + p20 * x24 + p27 * x25 + p34 * x26 + p41 * x27 + p48 * x28;
241         pc[27] = m28 = p7 * x22 + p14 * x23 + p21 * x24 + p28 * x25 + p35 * x26 + p42 * x27 + p49 * x28;
242 
243         pc[28] = m29 = p1 * x29 + p8 * x30 + p15 * x31 + p22 * x32 + p29 * x33 + p36 * x34 + p43 * x35;
244         pc[29] = m30 = p2 * x29 + p9 * x30 + p16 * x31 + p23 * x32 + p30 * x33 + p37 * x34 + p44 * x35;
245         pc[30] = m31 = p3 * x29 + p10 * x30 + p17 * x31 + p24 * x32 + p31 * x33 + p38 * x34 + p45 * x35;
246         pc[31] = m32 = p4 * x29 + p11 * x30 + p18 * x31 + p25 * x32 + p32 * x33 + p39 * x34 + p46 * x35;
247         pc[32] = m33 = p5 * x29 + p12 * x30 + p19 * x31 + p26 * x32 + p33 * x33 + p40 * x34 + p47 * x35;
248         pc[33] = m34 = p6 * x29 + p13 * x30 + p20 * x31 + p27 * x32 + p34 * x33 + p41 * x34 + p48 * x35;
249         pc[34] = m35 = p7 * x29 + p14 * x30 + p21 * x31 + p28 * x32 + p35 * x33 + p42 * x34 + p49 * x35;
250 
251         pc[35] = m36 = p1 * x36 + p8 * x37 + p15 * x38 + p22 * x39 + p29 * x40 + p36 * x41 + p43 * x42;
252         pc[36] = m37 = p2 * x36 + p9 * x37 + p16 * x38 + p23 * x39 + p30 * x40 + p37 * x41 + p44 * x42;
253         pc[37] = m38 = p3 * x36 + p10 * x37 + p17 * x38 + p24 * x39 + p31 * x40 + p38 * x41 + p45 * x42;
254         pc[38] = m39 = p4 * x36 + p11 * x37 + p18 * x38 + p25 * x39 + p32 * x40 + p39 * x41 + p46 * x42;
255         pc[39] = m40 = p5 * x36 + p12 * x37 + p19 * x38 + p26 * x39 + p33 * x40 + p40 * x41 + p47 * x42;
256         pc[40] = m41 = p6 * x36 + p13 * x37 + p20 * x38 + p27 * x39 + p34 * x40 + p41 * x41 + p48 * x42;
257         pc[41] = m42 = p7 * x36 + p14 * x37 + p21 * x38 + p28 * x39 + p35 * x40 + p42 * x41 + p49 * x42;
258 
259         pc[42] = m43 = p1 * x43 + p8 * x44 + p15 * x45 + p22 * x46 + p29 * x47 + p36 * x48 + p43 * x49;
260         pc[43] = m44 = p2 * x43 + p9 * x44 + p16 * x45 + p23 * x46 + p30 * x47 + p37 * x48 + p44 * x49;
261         pc[44] = m45 = p3 * x43 + p10 * x44 + p17 * x45 + p24 * x46 + p31 * x47 + p38 * x48 + p45 * x49;
262         pc[45] = m46 = p4 * x43 + p11 * x44 + p18 * x45 + p25 * x46 + p32 * x47 + p39 * x48 + p46 * x49;
263         pc[46] = m47 = p5 * x43 + p12 * x44 + p19 * x45 + p26 * x46 + p33 * x47 + p40 * x48 + p47 * x49;
264         pc[47] = m48 = p6 * x43 + p13 * x44 + p20 * x45 + p27 * x46 + p34 * x47 + p41 * x48 + p48 * x49;
265         pc[48] = m49 = p7 * x43 + p14 * x44 + p21 * x45 + p28 * x46 + p35 * x47 + p42 * x48 + p49 * x49;
266 
267         nz = bi[row + 1] - diag_offset[row] - 1;
268         pv += 49;
269         for (j = 0; j < nz; j++) {
270           x1  = pv[0];
271           x2  = pv[1];
272           x3  = pv[2];
273           x4  = pv[3];
274           x5  = pv[4];
275           x6  = pv[5];
276           x7  = pv[6];
277           x8  = pv[7];
278           x9  = pv[8];
279           x10 = pv[9];
280           x11 = pv[10];
281           x12 = pv[11];
282           x13 = pv[12];
283           x14 = pv[13];
284           x15 = pv[14];
285           x16 = pv[15];
286           x17 = pv[16];
287           x18 = pv[17];
288           x19 = pv[18];
289           x20 = pv[19];
290           x21 = pv[20];
291           x22 = pv[21];
292           x23 = pv[22];
293           x24 = pv[23];
294           x25 = pv[24];
295           x26 = pv[25];
296           x27 = pv[26];
297           x28 = pv[27];
298           x29 = pv[28];
299           x30 = pv[29];
300           x31 = pv[30];
301           x32 = pv[31];
302           x33 = pv[32];
303           x34 = pv[33];
304           x35 = pv[34];
305           x36 = pv[35];
306           x37 = pv[36];
307           x38 = pv[37];
308           x39 = pv[38];
309           x40 = pv[39];
310           x41 = pv[40];
311           x42 = pv[41];
312           x43 = pv[42];
313           x44 = pv[43];
314           x45 = pv[44];
315           x46 = pv[45];
316           x47 = pv[46];
317           x48 = pv[47];
318           x49 = pv[48];
319           x   = rtmp + 49 * pj[j];
320           x[0] -= m1 * x1 + m8 * x2 + m15 * x3 + m22 * x4 + m29 * x5 + m36 * x6 + m43 * x7;
321           x[1] -= m2 * x1 + m9 * x2 + m16 * x3 + m23 * x4 + m30 * x5 + m37 * x6 + m44 * x7;
322           x[2] -= m3 * x1 + m10 * x2 + m17 * x3 + m24 * x4 + m31 * x5 + m38 * x6 + m45 * x7;
323           x[3] -= m4 * x1 + m11 * x2 + m18 * x3 + m25 * x4 + m32 * x5 + m39 * x6 + m46 * x7;
324           x[4] -= m5 * x1 + m12 * x2 + m19 * x3 + m26 * x4 + m33 * x5 + m40 * x6 + m47 * x7;
325           x[5] -= m6 * x1 + m13 * x2 + m20 * x3 + m27 * x4 + m34 * x5 + m41 * x6 + m48 * x7;
326           x[6] -= m7 * x1 + m14 * x2 + m21 * x3 + m28 * x4 + m35 * x5 + m42 * x6 + m49 * x7;
327 
328           x[7] -= m1 * x8 + m8 * x9 + m15 * x10 + m22 * x11 + m29 * x12 + m36 * x13 + m43 * x14;
329           x[8] -= m2 * x8 + m9 * x9 + m16 * x10 + m23 * x11 + m30 * x12 + m37 * x13 + m44 * x14;
330           x[9] -= m3 * x8 + m10 * x9 + m17 * x10 + m24 * x11 + m31 * x12 + m38 * x13 + m45 * x14;
331           x[10] -= m4 * x8 + m11 * x9 + m18 * x10 + m25 * x11 + m32 * x12 + m39 * x13 + m46 * x14;
332           x[11] -= m5 * x8 + m12 * x9 + m19 * x10 + m26 * x11 + m33 * x12 + m40 * x13 + m47 * x14;
333           x[12] -= m6 * x8 + m13 * x9 + m20 * x10 + m27 * x11 + m34 * x12 + m41 * x13 + m48 * x14;
334           x[13] -= m7 * x8 + m14 * x9 + m21 * x10 + m28 * x11 + m35 * x12 + m42 * x13 + m49 * x14;
335 
336           x[14] -= m1 * x15 + m8 * x16 + m15 * x17 + m22 * x18 + m29 * x19 + m36 * x20 + m43 * x21;
337           x[15] -= m2 * x15 + m9 * x16 + m16 * x17 + m23 * x18 + m30 * x19 + m37 * x20 + m44 * x21;
338           x[16] -= m3 * x15 + m10 * x16 + m17 * x17 + m24 * x18 + m31 * x19 + m38 * x20 + m45 * x21;
339           x[17] -= m4 * x15 + m11 * x16 + m18 * x17 + m25 * x18 + m32 * x19 + m39 * x20 + m46 * x21;
340           x[18] -= m5 * x15 + m12 * x16 + m19 * x17 + m26 * x18 + m33 * x19 + m40 * x20 + m47 * x21;
341           x[19] -= m6 * x15 + m13 * x16 + m20 * x17 + m27 * x18 + m34 * x19 + m41 * x20 + m48 * x21;
342           x[20] -= m7 * x15 + m14 * x16 + m21 * x17 + m28 * x18 + m35 * x19 + m42 * x20 + m49 * x21;
343 
344           x[21] -= m1 * x22 + m8 * x23 + m15 * x24 + m22 * x25 + m29 * x26 + m36 * x27 + m43 * x28;
345           x[22] -= m2 * x22 + m9 * x23 + m16 * x24 + m23 * x25 + m30 * x26 + m37 * x27 + m44 * x28;
346           x[23] -= m3 * x22 + m10 * x23 + m17 * x24 + m24 * x25 + m31 * x26 + m38 * x27 + m45 * x28;
347           x[24] -= m4 * x22 + m11 * x23 + m18 * x24 + m25 * x25 + m32 * x26 + m39 * x27 + m46 * x28;
348           x[25] -= m5 * x22 + m12 * x23 + m19 * x24 + m26 * x25 + m33 * x26 + m40 * x27 + m47 * x28;
349           x[26] -= m6 * x22 + m13 * x23 + m20 * x24 + m27 * x25 + m34 * x26 + m41 * x27 + m48 * x28;
350           x[27] -= m7 * x22 + m14 * x23 + m21 * x24 + m28 * x25 + m35 * x26 + m42 * x27 + m49 * x28;
351 
352           x[28] -= m1 * x29 + m8 * x30 + m15 * x31 + m22 * x32 + m29 * x33 + m36 * x34 + m43 * x35;
353           x[29] -= m2 * x29 + m9 * x30 + m16 * x31 + m23 * x32 + m30 * x33 + m37 * x34 + m44 * x35;
354           x[30] -= m3 * x29 + m10 * x30 + m17 * x31 + m24 * x32 + m31 * x33 + m38 * x34 + m45 * x35;
355           x[31] -= m4 * x29 + m11 * x30 + m18 * x31 + m25 * x32 + m32 * x33 + m39 * x34 + m46 * x35;
356           x[32] -= m5 * x29 + m12 * x30 + m19 * x31 + m26 * x32 + m33 * x33 + m40 * x34 + m47 * x35;
357           x[33] -= m6 * x29 + m13 * x30 + m20 * x31 + m27 * x32 + m34 * x33 + m41 * x34 + m48 * x35;
358           x[34] -= m7 * x29 + m14 * x30 + m21 * x31 + m28 * x32 + m35 * x33 + m42 * x34 + m49 * x35;
359 
360           x[35] -= m1 * x36 + m8 * x37 + m15 * x38 + m22 * x39 + m29 * x40 + m36 * x41 + m43 * x42;
361           x[36] -= m2 * x36 + m9 * x37 + m16 * x38 + m23 * x39 + m30 * x40 + m37 * x41 + m44 * x42;
362           x[37] -= m3 * x36 + m10 * x37 + m17 * x38 + m24 * x39 + m31 * x40 + m38 * x41 + m45 * x42;
363           x[38] -= m4 * x36 + m11 * x37 + m18 * x38 + m25 * x39 + m32 * x40 + m39 * x41 + m46 * x42;
364           x[39] -= m5 * x36 + m12 * x37 + m19 * x38 + m26 * x39 + m33 * x40 + m40 * x41 + m47 * x42;
365           x[40] -= m6 * x36 + m13 * x37 + m20 * x38 + m27 * x39 + m34 * x40 + m41 * x41 + m48 * x42;
366           x[41] -= m7 * x36 + m14 * x37 + m21 * x38 + m28 * x39 + m35 * x40 + m42 * x41 + m49 * x42;
367 
368           x[42] -= m1 * x43 + m8 * x44 + m15 * x45 + m22 * x46 + m29 * x47 + m36 * x48 + m43 * x49;
369           x[43] -= m2 * x43 + m9 * x44 + m16 * x45 + m23 * x46 + m30 * x47 + m37 * x48 + m44 * x49;
370           x[44] -= m3 * x43 + m10 * x44 + m17 * x45 + m24 * x46 + m31 * x47 + m38 * x48 + m45 * x49;
371           x[45] -= m4 * x43 + m11 * x44 + m18 * x45 + m25 * x46 + m32 * x47 + m39 * x48 + m46 * x49;
372           x[46] -= m5 * x43 + m12 * x44 + m19 * x45 + m26 * x46 + m33 * x47 + m40 * x48 + m47 * x49;
373           x[47] -= m6 * x43 + m13 * x44 + m20 * x45 + m27 * x46 + m34 * x47 + m41 * x48 + m48 * x49;
374           x[48] -= m7 * x43 + m14 * x44 + m21 * x45 + m28 * x46 + m35 * x47 + m42 * x48 + m49 * x49;
375           pv += 49;
376         }
377         PetscCall(PetscLogFlops(686.0 * nz + 637.0));
378       }
379       row = *ajtmp++;
380     }
381     /* finished row so stick it into b->a */
382     pv = ba + 49 * bi[i];
383     pj = bj + bi[i];
384     nz = bi[i + 1] - bi[i];
385     for (j = 0; j < nz; j++) {
386       x      = rtmp + 49 * pj[j];
387       pv[0]  = x[0];
388       pv[1]  = x[1];
389       pv[2]  = x[2];
390       pv[3]  = x[3];
391       pv[4]  = x[4];
392       pv[5]  = x[5];
393       pv[6]  = x[6];
394       pv[7]  = x[7];
395       pv[8]  = x[8];
396       pv[9]  = x[9];
397       pv[10] = x[10];
398       pv[11] = x[11];
399       pv[12] = x[12];
400       pv[13] = x[13];
401       pv[14] = x[14];
402       pv[15] = x[15];
403       pv[16] = x[16];
404       pv[17] = x[17];
405       pv[18] = x[18];
406       pv[19] = x[19];
407       pv[20] = x[20];
408       pv[21] = x[21];
409       pv[22] = x[22];
410       pv[23] = x[23];
411       pv[24] = x[24];
412       pv[25] = x[25];
413       pv[26] = x[26];
414       pv[27] = x[27];
415       pv[28] = x[28];
416       pv[29] = x[29];
417       pv[30] = x[30];
418       pv[31] = x[31];
419       pv[32] = x[32];
420       pv[33] = x[33];
421       pv[34] = x[34];
422       pv[35] = x[35];
423       pv[36] = x[36];
424       pv[37] = x[37];
425       pv[38] = x[38];
426       pv[39] = x[39];
427       pv[40] = x[40];
428       pv[41] = x[41];
429       pv[42] = x[42];
430       pv[43] = x[43];
431       pv[44] = x[44];
432       pv[45] = x[45];
433       pv[46] = x[46];
434       pv[47] = x[47];
435       pv[48] = x[48];
436       pv += 49;
437     }
438     /* invert diagonal block */
439     w = ba + 49 * diag_offset[i];
440     PetscCall(PetscKernel_A_gets_inverse_A_7(w, shift, allowzeropivot, &zeropivotdetected));
441     if (zeropivotdetected) C->factorerrortype = MAT_FACTOR_NUMERIC_ZEROPIVOT;
442   }
443 
444   PetscCall(PetscFree(rtmp));
445   PetscCall(ISRestoreIndices(isicol, &ic));
446   PetscCall(ISRestoreIndices(isrow, &r));
447 
448   C->ops->solve          = MatSolve_SeqBAIJ_7_inplace;
449   C->ops->solvetranspose = MatSolveTranspose_SeqBAIJ_7_inplace;
450   C->assembled           = PETSC_TRUE;
451 
452   PetscCall(PetscLogFlops(1.333333333333 * 7 * 7 * 7 * b->mbs)); /* from inverting diagonal blocks */
453   PetscFunctionReturn(0);
454 }
455 
456 PetscErrorCode MatLUFactorNumeric_SeqBAIJ_7(Mat B, Mat A, const MatFactorInfo *info) {
457   Mat             C = B;
458   Mat_SeqBAIJ    *a = (Mat_SeqBAIJ *)A->data, *b = (Mat_SeqBAIJ *)C->data;
459   IS              isrow = b->row, isicol = b->icol;
460   const PetscInt *r, *ic;
461   PetscInt        i, j, k, nz, nzL, row;
462   const PetscInt  n = a->mbs, *ai = a->i, *aj = a->j, *bi = b->i, *bj = b->j;
463   const PetscInt *ajtmp, *bjtmp, *bdiag = b->diag, *pj, bs2 = a->bs2;
464   MatScalar      *rtmp, *pc, *mwork, *v, *pv, *aa = a->a;
465   PetscInt        flg;
466   PetscReal       shift = info->shiftamount;
467   PetscBool       allowzeropivot, zeropivotdetected;
468 
469   PetscFunctionBegin;
470   allowzeropivot = PetscNot(A->erroriffailure);
471   PetscCall(ISGetIndices(isrow, &r));
472   PetscCall(ISGetIndices(isicol, &ic));
473 
474   /* generate work space needed by the factorization */
475   PetscCall(PetscMalloc2(bs2 * n, &rtmp, bs2, &mwork));
476   PetscCall(PetscArrayzero(rtmp, bs2 * n));
477 
478   for (i = 0; i < n; i++) {
479     /* zero rtmp */
480     /* L part */
481     nz    = bi[i + 1] - bi[i];
482     bjtmp = bj + bi[i];
483     for (j = 0; j < nz; j++) { PetscCall(PetscArrayzero(rtmp + bs2 * bjtmp[j], bs2)); }
484 
485     /* U part */
486     nz    = bdiag[i] - bdiag[i + 1];
487     bjtmp = bj + bdiag[i + 1] + 1;
488     for (j = 0; j < nz; j++) { PetscCall(PetscArrayzero(rtmp + bs2 * bjtmp[j], bs2)); }
489 
490     /* load in initial (unfactored row) */
491     nz    = ai[r[i] + 1] - ai[r[i]];
492     ajtmp = aj + ai[r[i]];
493     v     = aa + bs2 * ai[r[i]];
494     for (j = 0; j < nz; j++) { PetscCall(PetscArraycpy(rtmp + bs2 * ic[ajtmp[j]], v + bs2 * j, bs2)); }
495 
496     /* elimination */
497     bjtmp = bj + bi[i];
498     nzL   = bi[i + 1] - bi[i];
499     for (k = 0; k < nzL; k++) {
500       row = bjtmp[k];
501       pc  = rtmp + bs2 * row;
502       for (flg = 0, j = 0; j < bs2; j++) {
503         if (pc[j] != 0.0) {
504           flg = 1;
505           break;
506         }
507       }
508       if (flg) {
509         pv = b->a + bs2 * bdiag[row];
510         /* PetscKernel_A_gets_A_times_B(bs,pc,pv,mwork); *pc = *pc * (*pv); */
511         PetscCall(PetscKernel_A_gets_A_times_B_7(pc, pv, mwork));
512 
513         pj = b->j + bdiag[row + 1] + 1; /* beginning of U(row,:) */
514         pv = b->a + bs2 * (bdiag[row + 1] + 1);
515         nz = bdiag[row] - bdiag[row + 1] - 1; /* num of entries inU(row,:), excluding diag */
516         for (j = 0; j < nz; j++) {
517           /* PetscKernel_A_gets_A_minus_B_times_C(bs,rtmp+bs2*pj[j],pc,pv+bs2*j); */
518           /* rtmp+bs2*pj[j] = rtmp+bs2*pj[j] - (*pc)*(pv+bs2*j) */
519           v = rtmp + bs2 * pj[j];
520           PetscCall(PetscKernel_A_gets_A_minus_B_times_C_7(v, pc, pv));
521           pv += bs2;
522         }
523         PetscCall(PetscLogFlops(686.0 * nz + 637)); /* flops = 2*bs^3*nz + 2*bs^3 - bs2) */
524       }
525     }
526 
527     /* finished row so stick it into b->a */
528     /* L part */
529     pv = b->a + bs2 * bi[i];
530     pj = b->j + bi[i];
531     nz = bi[i + 1] - bi[i];
532     for (j = 0; j < nz; j++) { PetscCall(PetscArraycpy(pv + bs2 * j, rtmp + bs2 * pj[j], bs2)); }
533 
534     /* Mark diagonal and invert diagonal for simpler triangular solves */
535     pv = b->a + bs2 * bdiag[i];
536     pj = b->j + bdiag[i];
537     PetscCall(PetscArraycpy(pv, rtmp + bs2 * pj[0], bs2));
538     PetscCall(PetscKernel_A_gets_inverse_A_7(pv, shift, allowzeropivot, &zeropivotdetected));
539     if (zeropivotdetected) C->factorerrortype = MAT_FACTOR_NUMERIC_ZEROPIVOT;
540 
541     /* U part */
542     pv = b->a + bs2 * (bdiag[i + 1] + 1);
543     pj = b->j + bdiag[i + 1] + 1;
544     nz = bdiag[i] - bdiag[i + 1] - 1;
545     for (j = 0; j < nz; j++) { PetscCall(PetscArraycpy(pv + bs2 * j, rtmp + bs2 * pj[j], bs2)); }
546   }
547 
548   PetscCall(PetscFree2(rtmp, mwork));
549   PetscCall(ISRestoreIndices(isicol, &ic));
550   PetscCall(ISRestoreIndices(isrow, &r));
551 
552   C->ops->solve          = MatSolve_SeqBAIJ_7;
553   C->ops->solvetranspose = MatSolveTranspose_SeqBAIJ_7;
554   C->assembled           = PETSC_TRUE;
555 
556   PetscCall(PetscLogFlops(1.333333333333 * 7 * 7 * 7 * n)); /* from inverting diagonal blocks */
557   PetscFunctionReturn(0);
558 }
559 
560 PetscErrorCode MatLUFactorNumeric_SeqBAIJ_7_NaturalOrdering_inplace(Mat C, Mat A, const MatFactorInfo *info) {
561   Mat_SeqBAIJ *a = (Mat_SeqBAIJ *)A->data, *b = (Mat_SeqBAIJ *)C->data;
562   PetscInt     i, j, n = a->mbs, *bi = b->i, *bj = b->j;
563   PetscInt    *ajtmpold, *ajtmp, nz, row;
564   PetscInt    *diag_offset = b->diag, *ai = a->i, *aj = a->j, *pj;
565   MatScalar   *pv, *v, *rtmp, *pc, *w, *x;
566   MatScalar    x1, x2, x3, x4, x5, x6, x7, x8, x9, x10, x11, x12, x13, x14, x15;
567   MatScalar    x16, x17, x18, x19, x20, x21, x22, x23, x24, x25;
568   MatScalar    p1, p2, p3, p4, p5, p6, p7, p8, p9, p10, p11, p12, p13, p14, p15;
569   MatScalar    p16, p17, p18, p19, p20, p21, p22, p23, p24, p25;
570   MatScalar    m1, m2, m3, m4, m5, m6, m7, m8, m9, m10, m11, m12, m13, m14, m15;
571   MatScalar    m16, m17, m18, m19, m20, m21, m22, m23, m24, m25;
572   MatScalar    p26, p27, p28, p29, p30, p31, p32, p33, p34, p35, p36;
573   MatScalar    p37, p38, p39, p40, p41, p42, p43, p44, p45, p46, p47, p48, p49;
574   MatScalar    x26, x27, x28, x29, x30, x31, x32, x33, x34, x35, x36;
575   MatScalar    x37, x38, x39, x40, x41, x42, x43, x44, x45, x46, x47, x48, x49;
576   MatScalar    m26, m27, m28, m29, m30, m31, m32, m33, m34, m35, m36;
577   MatScalar    m37, m38, m39, m40, m41, m42, m43, m44, m45, m46, m47, m48, m49;
578   MatScalar   *ba = b->a, *aa = a->a;
579   PetscReal    shift = info->shiftamount;
580   PetscBool    allowzeropivot, zeropivotdetected;
581 
582   PetscFunctionBegin;
583   allowzeropivot = PetscNot(A->erroriffailure);
584   PetscCall(PetscMalloc1(49 * (n + 1), &rtmp));
585   for (i = 0; i < n; i++) {
586     nz    = bi[i + 1] - bi[i];
587     ajtmp = bj + bi[i];
588     for (j = 0; j < nz; j++) {
589       x    = rtmp + 49 * ajtmp[j];
590       x[0] = x[1] = x[2] = x[3] = x[4] = x[5] = x[6] = x[7] = x[8] = x[9] = 0.0;
591       x[10] = x[11] = x[12] = x[13] = x[14] = x[15] = x[16] = x[17] = 0.0;
592       x[18] = x[19] = x[20] = x[21] = x[22] = x[23] = x[24] = x[25] = 0.0;
593       x[26] = x[27] = x[28] = x[29] = x[30] = x[31] = x[32] = x[33] = 0.0;
594       x[34] = x[35] = x[36] = x[37] = x[38] = x[39] = x[40] = x[41] = 0.0;
595       x[42] = x[43] = x[44] = x[45] = x[46] = x[47] = x[48] = 0.0;
596     }
597     /* load in initial (unfactored row) */
598     nz       = ai[i + 1] - ai[i];
599     ajtmpold = aj + ai[i];
600     v        = aa + 49 * ai[i];
601     for (j = 0; j < nz; j++) {
602       x     = rtmp + 49 * ajtmpold[j];
603       x[0]  = v[0];
604       x[1]  = v[1];
605       x[2]  = v[2];
606       x[3]  = v[3];
607       x[4]  = v[4];
608       x[5]  = v[5];
609       x[6]  = v[6];
610       x[7]  = v[7];
611       x[8]  = v[8];
612       x[9]  = v[9];
613       x[10] = v[10];
614       x[11] = v[11];
615       x[12] = v[12];
616       x[13] = v[13];
617       x[14] = v[14];
618       x[15] = v[15];
619       x[16] = v[16];
620       x[17] = v[17];
621       x[18] = v[18];
622       x[19] = v[19];
623       x[20] = v[20];
624       x[21] = v[21];
625       x[22] = v[22];
626       x[23] = v[23];
627       x[24] = v[24];
628       x[25] = v[25];
629       x[26] = v[26];
630       x[27] = v[27];
631       x[28] = v[28];
632       x[29] = v[29];
633       x[30] = v[30];
634       x[31] = v[31];
635       x[32] = v[32];
636       x[33] = v[33];
637       x[34] = v[34];
638       x[35] = v[35];
639       x[36] = v[36];
640       x[37] = v[37];
641       x[38] = v[38];
642       x[39] = v[39];
643       x[40] = v[40];
644       x[41] = v[41];
645       x[42] = v[42];
646       x[43] = v[43];
647       x[44] = v[44];
648       x[45] = v[45];
649       x[46] = v[46];
650       x[47] = v[47];
651       x[48] = v[48];
652       v += 49;
653     }
654     row = *ajtmp++;
655     while (row < i) {
656       pc  = rtmp + 49 * row;
657       p1  = pc[0];
658       p2  = pc[1];
659       p3  = pc[2];
660       p4  = pc[3];
661       p5  = pc[4];
662       p6  = pc[5];
663       p7  = pc[6];
664       p8  = pc[7];
665       p9  = pc[8];
666       p10 = pc[9];
667       p11 = pc[10];
668       p12 = pc[11];
669       p13 = pc[12];
670       p14 = pc[13];
671       p15 = pc[14];
672       p16 = pc[15];
673       p17 = pc[16];
674       p18 = pc[17];
675       p19 = pc[18];
676       p20 = pc[19];
677       p21 = pc[20];
678       p22 = pc[21];
679       p23 = pc[22];
680       p24 = pc[23];
681       p25 = pc[24];
682       p26 = pc[25];
683       p27 = pc[26];
684       p28 = pc[27];
685       p29 = pc[28];
686       p30 = pc[29];
687       p31 = pc[30];
688       p32 = pc[31];
689       p33 = pc[32];
690       p34 = pc[33];
691       p35 = pc[34];
692       p36 = pc[35];
693       p37 = pc[36];
694       p38 = pc[37];
695       p39 = pc[38];
696       p40 = pc[39];
697       p41 = pc[40];
698       p42 = pc[41];
699       p43 = pc[42];
700       p44 = pc[43];
701       p45 = pc[44];
702       p46 = pc[45];
703       p47 = pc[46];
704       p48 = pc[47];
705       p49 = pc[48];
706       if (p1 != 0.0 || p2 != 0.0 || p3 != 0.0 || p4 != 0.0 || p5 != 0.0 || p6 != 0.0 || p7 != 0.0 || p8 != 0.0 || p9 != 0.0 || p10 != 0.0 || p11 != 0.0 || p12 != 0.0 || p13 != 0.0 || p14 != 0.0 || p15 != 0.0 || p16 != 0.0 || p17 != 0.0 || p18 != 0.0 || p19 != 0.0 || p20 != 0.0 || p21 != 0.0 || p22 != 0.0 || p23 != 0.0 || p24 != 0.0 || p25 != 0.0 || p26 != 0.0 || p27 != 0.0 || p28 != 0.0 || p29 != 0.0 || p30 != 0.0 || p31 != 0.0 || p32 != 0.0 || p33 != 0.0 || p34 != 0.0 || p35 != 0.0 || p36 != 0.0 || p37 != 0.0 || p38 != 0.0 || p39 != 0.0 || p40 != 0.0 || p41 != 0.0 || p42 != 0.0 || p43 != 0.0 || p44 != 0.0 || p45 != 0.0 || p46 != 0.0 || p47 != 0.0 || p48 != 0.0 || p49 != 0.0) {
707         pv    = ba + 49 * diag_offset[row];
708         pj    = bj + diag_offset[row] + 1;
709         x1    = pv[0];
710         x2    = pv[1];
711         x3    = pv[2];
712         x4    = pv[3];
713         x5    = pv[4];
714         x6    = pv[5];
715         x7    = pv[6];
716         x8    = pv[7];
717         x9    = pv[8];
718         x10   = pv[9];
719         x11   = pv[10];
720         x12   = pv[11];
721         x13   = pv[12];
722         x14   = pv[13];
723         x15   = pv[14];
724         x16   = pv[15];
725         x17   = pv[16];
726         x18   = pv[17];
727         x19   = pv[18];
728         x20   = pv[19];
729         x21   = pv[20];
730         x22   = pv[21];
731         x23   = pv[22];
732         x24   = pv[23];
733         x25   = pv[24];
734         x26   = pv[25];
735         x27   = pv[26];
736         x28   = pv[27];
737         x29   = pv[28];
738         x30   = pv[29];
739         x31   = pv[30];
740         x32   = pv[31];
741         x33   = pv[32];
742         x34   = pv[33];
743         x35   = pv[34];
744         x36   = pv[35];
745         x37   = pv[36];
746         x38   = pv[37];
747         x39   = pv[38];
748         x40   = pv[39];
749         x41   = pv[40];
750         x42   = pv[41];
751         x43   = pv[42];
752         x44   = pv[43];
753         x45   = pv[44];
754         x46   = pv[45];
755         x47   = pv[46];
756         x48   = pv[47];
757         x49   = pv[48];
758         pc[0] = m1 = p1 * x1 + p8 * x2 + p15 * x3 + p22 * x4 + p29 * x5 + p36 * x6 + p43 * x7;
759         pc[1] = m2 = p2 * x1 + p9 * x2 + p16 * x3 + p23 * x4 + p30 * x5 + p37 * x6 + p44 * x7;
760         pc[2] = m3 = p3 * x1 + p10 * x2 + p17 * x3 + p24 * x4 + p31 * x5 + p38 * x6 + p45 * x7;
761         pc[3] = m4 = p4 * x1 + p11 * x2 + p18 * x3 + p25 * x4 + p32 * x5 + p39 * x6 + p46 * x7;
762         pc[4] = m5 = p5 * x1 + p12 * x2 + p19 * x3 + p26 * x4 + p33 * x5 + p40 * x6 + p47 * x7;
763         pc[5] = m6 = p6 * x1 + p13 * x2 + p20 * x3 + p27 * x4 + p34 * x5 + p41 * x6 + p48 * x7;
764         pc[6] = m7 = p7 * x1 + p14 * x2 + p21 * x3 + p28 * x4 + p35 * x5 + p42 * x6 + p49 * x7;
765 
766         pc[7] = m8 = p1 * x8 + p8 * x9 + p15 * x10 + p22 * x11 + p29 * x12 + p36 * x13 + p43 * x14;
767         pc[8] = m9 = p2 * x8 + p9 * x9 + p16 * x10 + p23 * x11 + p30 * x12 + p37 * x13 + p44 * x14;
768         pc[9] = m10 = p3 * x8 + p10 * x9 + p17 * x10 + p24 * x11 + p31 * x12 + p38 * x13 + p45 * x14;
769         pc[10] = m11 = p4 * x8 + p11 * x9 + p18 * x10 + p25 * x11 + p32 * x12 + p39 * x13 + p46 * x14;
770         pc[11] = m12 = p5 * x8 + p12 * x9 + p19 * x10 + p26 * x11 + p33 * x12 + p40 * x13 + p47 * x14;
771         pc[12] = m13 = p6 * x8 + p13 * x9 + p20 * x10 + p27 * x11 + p34 * x12 + p41 * x13 + p48 * x14;
772         pc[13] = m14 = p7 * x8 + p14 * x9 + p21 * x10 + p28 * x11 + p35 * x12 + p42 * x13 + p49 * x14;
773 
774         pc[14] = m15 = p1 * x15 + p8 * x16 + p15 * x17 + p22 * x18 + p29 * x19 + p36 * x20 + p43 * x21;
775         pc[15] = m16 = p2 * x15 + p9 * x16 + p16 * x17 + p23 * x18 + p30 * x19 + p37 * x20 + p44 * x21;
776         pc[16] = m17 = p3 * x15 + p10 * x16 + p17 * x17 + p24 * x18 + p31 * x19 + p38 * x20 + p45 * x21;
777         pc[17] = m18 = p4 * x15 + p11 * x16 + p18 * x17 + p25 * x18 + p32 * x19 + p39 * x20 + p46 * x21;
778         pc[18] = m19 = p5 * x15 + p12 * x16 + p19 * x17 + p26 * x18 + p33 * x19 + p40 * x20 + p47 * x21;
779         pc[19] = m20 = p6 * x15 + p13 * x16 + p20 * x17 + p27 * x18 + p34 * x19 + p41 * x20 + p48 * x21;
780         pc[20] = m21 = p7 * x15 + p14 * x16 + p21 * x17 + p28 * x18 + p35 * x19 + p42 * x20 + p49 * x21;
781 
782         pc[21] = m22 = p1 * x22 + p8 * x23 + p15 * x24 + p22 * x25 + p29 * x26 + p36 * x27 + p43 * x28;
783         pc[22] = m23 = p2 * x22 + p9 * x23 + p16 * x24 + p23 * x25 + p30 * x26 + p37 * x27 + p44 * x28;
784         pc[23] = m24 = p3 * x22 + p10 * x23 + p17 * x24 + p24 * x25 + p31 * x26 + p38 * x27 + p45 * x28;
785         pc[24] = m25 = p4 * x22 + p11 * x23 + p18 * x24 + p25 * x25 + p32 * x26 + p39 * x27 + p46 * x28;
786         pc[25] = m26 = p5 * x22 + p12 * x23 + p19 * x24 + p26 * x25 + p33 * x26 + p40 * x27 + p47 * x28;
787         pc[26] = m27 = p6 * x22 + p13 * x23 + p20 * x24 + p27 * x25 + p34 * x26 + p41 * x27 + p48 * x28;
788         pc[27] = m28 = p7 * x22 + p14 * x23 + p21 * x24 + p28 * x25 + p35 * x26 + p42 * x27 + p49 * x28;
789 
790         pc[28] = m29 = p1 * x29 + p8 * x30 + p15 * x31 + p22 * x32 + p29 * x33 + p36 * x34 + p43 * x35;
791         pc[29] = m30 = p2 * x29 + p9 * x30 + p16 * x31 + p23 * x32 + p30 * x33 + p37 * x34 + p44 * x35;
792         pc[30] = m31 = p3 * x29 + p10 * x30 + p17 * x31 + p24 * x32 + p31 * x33 + p38 * x34 + p45 * x35;
793         pc[31] = m32 = p4 * x29 + p11 * x30 + p18 * x31 + p25 * x32 + p32 * x33 + p39 * x34 + p46 * x35;
794         pc[32] = m33 = p5 * x29 + p12 * x30 + p19 * x31 + p26 * x32 + p33 * x33 + p40 * x34 + p47 * x35;
795         pc[33] = m34 = p6 * x29 + p13 * x30 + p20 * x31 + p27 * x32 + p34 * x33 + p41 * x34 + p48 * x35;
796         pc[34] = m35 = p7 * x29 + p14 * x30 + p21 * x31 + p28 * x32 + p35 * x33 + p42 * x34 + p49 * x35;
797 
798         pc[35] = m36 = p1 * x36 + p8 * x37 + p15 * x38 + p22 * x39 + p29 * x40 + p36 * x41 + p43 * x42;
799         pc[36] = m37 = p2 * x36 + p9 * x37 + p16 * x38 + p23 * x39 + p30 * x40 + p37 * x41 + p44 * x42;
800         pc[37] = m38 = p3 * x36 + p10 * x37 + p17 * x38 + p24 * x39 + p31 * x40 + p38 * x41 + p45 * x42;
801         pc[38] = m39 = p4 * x36 + p11 * x37 + p18 * x38 + p25 * x39 + p32 * x40 + p39 * x41 + p46 * x42;
802         pc[39] = m40 = p5 * x36 + p12 * x37 + p19 * x38 + p26 * x39 + p33 * x40 + p40 * x41 + p47 * x42;
803         pc[40] = m41 = p6 * x36 + p13 * x37 + p20 * x38 + p27 * x39 + p34 * x40 + p41 * x41 + p48 * x42;
804         pc[41] = m42 = p7 * x36 + p14 * x37 + p21 * x38 + p28 * x39 + p35 * x40 + p42 * x41 + p49 * x42;
805 
806         pc[42] = m43 = p1 * x43 + p8 * x44 + p15 * x45 + p22 * x46 + p29 * x47 + p36 * x48 + p43 * x49;
807         pc[43] = m44 = p2 * x43 + p9 * x44 + p16 * x45 + p23 * x46 + p30 * x47 + p37 * x48 + p44 * x49;
808         pc[44] = m45 = p3 * x43 + p10 * x44 + p17 * x45 + p24 * x46 + p31 * x47 + p38 * x48 + p45 * x49;
809         pc[45] = m46 = p4 * x43 + p11 * x44 + p18 * x45 + p25 * x46 + p32 * x47 + p39 * x48 + p46 * x49;
810         pc[46] = m47 = p5 * x43 + p12 * x44 + p19 * x45 + p26 * x46 + p33 * x47 + p40 * x48 + p47 * x49;
811         pc[47] = m48 = p6 * x43 + p13 * x44 + p20 * x45 + p27 * x46 + p34 * x47 + p41 * x48 + p48 * x49;
812         pc[48] = m49 = p7 * x43 + p14 * x44 + p21 * x45 + p28 * x46 + p35 * x47 + p42 * x48 + p49 * x49;
813 
814         nz = bi[row + 1] - diag_offset[row] - 1;
815         pv += 49;
816         for (j = 0; j < nz; j++) {
817           x1  = pv[0];
818           x2  = pv[1];
819           x3  = pv[2];
820           x4  = pv[3];
821           x5  = pv[4];
822           x6  = pv[5];
823           x7  = pv[6];
824           x8  = pv[7];
825           x9  = pv[8];
826           x10 = pv[9];
827           x11 = pv[10];
828           x12 = pv[11];
829           x13 = pv[12];
830           x14 = pv[13];
831           x15 = pv[14];
832           x16 = pv[15];
833           x17 = pv[16];
834           x18 = pv[17];
835           x19 = pv[18];
836           x20 = pv[19];
837           x21 = pv[20];
838           x22 = pv[21];
839           x23 = pv[22];
840           x24 = pv[23];
841           x25 = pv[24];
842           x26 = pv[25];
843           x27 = pv[26];
844           x28 = pv[27];
845           x29 = pv[28];
846           x30 = pv[29];
847           x31 = pv[30];
848           x32 = pv[31];
849           x33 = pv[32];
850           x34 = pv[33];
851           x35 = pv[34];
852           x36 = pv[35];
853           x37 = pv[36];
854           x38 = pv[37];
855           x39 = pv[38];
856           x40 = pv[39];
857           x41 = pv[40];
858           x42 = pv[41];
859           x43 = pv[42];
860           x44 = pv[43];
861           x45 = pv[44];
862           x46 = pv[45];
863           x47 = pv[46];
864           x48 = pv[47];
865           x49 = pv[48];
866           x   = rtmp + 49 * pj[j];
867           x[0] -= m1 * x1 + m8 * x2 + m15 * x3 + m22 * x4 + m29 * x5 + m36 * x6 + m43 * x7;
868           x[1] -= m2 * x1 + m9 * x2 + m16 * x3 + m23 * x4 + m30 * x5 + m37 * x6 + m44 * x7;
869           x[2] -= m3 * x1 + m10 * x2 + m17 * x3 + m24 * x4 + m31 * x5 + m38 * x6 + m45 * x7;
870           x[3] -= m4 * x1 + m11 * x2 + m18 * x3 + m25 * x4 + m32 * x5 + m39 * x6 + m46 * x7;
871           x[4] -= m5 * x1 + m12 * x2 + m19 * x3 + m26 * x4 + m33 * x5 + m40 * x6 + m47 * x7;
872           x[5] -= m6 * x1 + m13 * x2 + m20 * x3 + m27 * x4 + m34 * x5 + m41 * x6 + m48 * x7;
873           x[6] -= m7 * x1 + m14 * x2 + m21 * x3 + m28 * x4 + m35 * x5 + m42 * x6 + m49 * x7;
874 
875           x[7] -= m1 * x8 + m8 * x9 + m15 * x10 + m22 * x11 + m29 * x12 + m36 * x13 + m43 * x14;
876           x[8] -= m2 * x8 + m9 * x9 + m16 * x10 + m23 * x11 + m30 * x12 + m37 * x13 + m44 * x14;
877           x[9] -= m3 * x8 + m10 * x9 + m17 * x10 + m24 * x11 + m31 * x12 + m38 * x13 + m45 * x14;
878           x[10] -= m4 * x8 + m11 * x9 + m18 * x10 + m25 * x11 + m32 * x12 + m39 * x13 + m46 * x14;
879           x[11] -= m5 * x8 + m12 * x9 + m19 * x10 + m26 * x11 + m33 * x12 + m40 * x13 + m47 * x14;
880           x[12] -= m6 * x8 + m13 * x9 + m20 * x10 + m27 * x11 + m34 * x12 + m41 * x13 + m48 * x14;
881           x[13] -= m7 * x8 + m14 * x9 + m21 * x10 + m28 * x11 + m35 * x12 + m42 * x13 + m49 * x14;
882 
883           x[14] -= m1 * x15 + m8 * x16 + m15 * x17 + m22 * x18 + m29 * x19 + m36 * x20 + m43 * x21;
884           x[15] -= m2 * x15 + m9 * x16 + m16 * x17 + m23 * x18 + m30 * x19 + m37 * x20 + m44 * x21;
885           x[16] -= m3 * x15 + m10 * x16 + m17 * x17 + m24 * x18 + m31 * x19 + m38 * x20 + m45 * x21;
886           x[17] -= m4 * x15 + m11 * x16 + m18 * x17 + m25 * x18 + m32 * x19 + m39 * x20 + m46 * x21;
887           x[18] -= m5 * x15 + m12 * x16 + m19 * x17 + m26 * x18 + m33 * x19 + m40 * x20 + m47 * x21;
888           x[19] -= m6 * x15 + m13 * x16 + m20 * x17 + m27 * x18 + m34 * x19 + m41 * x20 + m48 * x21;
889           x[20] -= m7 * x15 + m14 * x16 + m21 * x17 + m28 * x18 + m35 * x19 + m42 * x20 + m49 * x21;
890 
891           x[21] -= m1 * x22 + m8 * x23 + m15 * x24 + m22 * x25 + m29 * x26 + m36 * x27 + m43 * x28;
892           x[22] -= m2 * x22 + m9 * x23 + m16 * x24 + m23 * x25 + m30 * x26 + m37 * x27 + m44 * x28;
893           x[23] -= m3 * x22 + m10 * x23 + m17 * x24 + m24 * x25 + m31 * x26 + m38 * x27 + m45 * x28;
894           x[24] -= m4 * x22 + m11 * x23 + m18 * x24 + m25 * x25 + m32 * x26 + m39 * x27 + m46 * x28;
895           x[25] -= m5 * x22 + m12 * x23 + m19 * x24 + m26 * x25 + m33 * x26 + m40 * x27 + m47 * x28;
896           x[26] -= m6 * x22 + m13 * x23 + m20 * x24 + m27 * x25 + m34 * x26 + m41 * x27 + m48 * x28;
897           x[27] -= m7 * x22 + m14 * x23 + m21 * x24 + m28 * x25 + m35 * x26 + m42 * x27 + m49 * x28;
898 
899           x[28] -= m1 * x29 + m8 * x30 + m15 * x31 + m22 * x32 + m29 * x33 + m36 * x34 + m43 * x35;
900           x[29] -= m2 * x29 + m9 * x30 + m16 * x31 + m23 * x32 + m30 * x33 + m37 * x34 + m44 * x35;
901           x[30] -= m3 * x29 + m10 * x30 + m17 * x31 + m24 * x32 + m31 * x33 + m38 * x34 + m45 * x35;
902           x[31] -= m4 * x29 + m11 * x30 + m18 * x31 + m25 * x32 + m32 * x33 + m39 * x34 + m46 * x35;
903           x[32] -= m5 * x29 + m12 * x30 + m19 * x31 + m26 * x32 + m33 * x33 + m40 * x34 + m47 * x35;
904           x[33] -= m6 * x29 + m13 * x30 + m20 * x31 + m27 * x32 + m34 * x33 + m41 * x34 + m48 * x35;
905           x[34] -= m7 * x29 + m14 * x30 + m21 * x31 + m28 * x32 + m35 * x33 + m42 * x34 + m49 * x35;
906 
907           x[35] -= m1 * x36 + m8 * x37 + m15 * x38 + m22 * x39 + m29 * x40 + m36 * x41 + m43 * x42;
908           x[36] -= m2 * x36 + m9 * x37 + m16 * x38 + m23 * x39 + m30 * x40 + m37 * x41 + m44 * x42;
909           x[37] -= m3 * x36 + m10 * x37 + m17 * x38 + m24 * x39 + m31 * x40 + m38 * x41 + m45 * x42;
910           x[38] -= m4 * x36 + m11 * x37 + m18 * x38 + m25 * x39 + m32 * x40 + m39 * x41 + m46 * x42;
911           x[39] -= m5 * x36 + m12 * x37 + m19 * x38 + m26 * x39 + m33 * x40 + m40 * x41 + m47 * x42;
912           x[40] -= m6 * x36 + m13 * x37 + m20 * x38 + m27 * x39 + m34 * x40 + m41 * x41 + m48 * x42;
913           x[41] -= m7 * x36 + m14 * x37 + m21 * x38 + m28 * x39 + m35 * x40 + m42 * x41 + m49 * x42;
914 
915           x[42] -= m1 * x43 + m8 * x44 + m15 * x45 + m22 * x46 + m29 * x47 + m36 * x48 + m43 * x49;
916           x[43] -= m2 * x43 + m9 * x44 + m16 * x45 + m23 * x46 + m30 * x47 + m37 * x48 + m44 * x49;
917           x[44] -= m3 * x43 + m10 * x44 + m17 * x45 + m24 * x46 + m31 * x47 + m38 * x48 + m45 * x49;
918           x[45] -= m4 * x43 + m11 * x44 + m18 * x45 + m25 * x46 + m32 * x47 + m39 * x48 + m46 * x49;
919           x[46] -= m5 * x43 + m12 * x44 + m19 * x45 + m26 * x46 + m33 * x47 + m40 * x48 + m47 * x49;
920           x[47] -= m6 * x43 + m13 * x44 + m20 * x45 + m27 * x46 + m34 * x47 + m41 * x48 + m48 * x49;
921           x[48] -= m7 * x43 + m14 * x44 + m21 * x45 + m28 * x46 + m35 * x47 + m42 * x48 + m49 * x49;
922           pv += 49;
923         }
924         PetscCall(PetscLogFlops(686.0 * nz + 637.0));
925       }
926       row = *ajtmp++;
927     }
928     /* finished row so stick it into b->a */
929     pv = ba + 49 * bi[i];
930     pj = bj + bi[i];
931     nz = bi[i + 1] - bi[i];
932     for (j = 0; j < nz; j++) {
933       x      = rtmp + 49 * pj[j];
934       pv[0]  = x[0];
935       pv[1]  = x[1];
936       pv[2]  = x[2];
937       pv[3]  = x[3];
938       pv[4]  = x[4];
939       pv[5]  = x[5];
940       pv[6]  = x[6];
941       pv[7]  = x[7];
942       pv[8]  = x[8];
943       pv[9]  = x[9];
944       pv[10] = x[10];
945       pv[11] = x[11];
946       pv[12] = x[12];
947       pv[13] = x[13];
948       pv[14] = x[14];
949       pv[15] = x[15];
950       pv[16] = x[16];
951       pv[17] = x[17];
952       pv[18] = x[18];
953       pv[19] = x[19];
954       pv[20] = x[20];
955       pv[21] = x[21];
956       pv[22] = x[22];
957       pv[23] = x[23];
958       pv[24] = x[24];
959       pv[25] = x[25];
960       pv[26] = x[26];
961       pv[27] = x[27];
962       pv[28] = x[28];
963       pv[29] = x[29];
964       pv[30] = x[30];
965       pv[31] = x[31];
966       pv[32] = x[32];
967       pv[33] = x[33];
968       pv[34] = x[34];
969       pv[35] = x[35];
970       pv[36] = x[36];
971       pv[37] = x[37];
972       pv[38] = x[38];
973       pv[39] = x[39];
974       pv[40] = x[40];
975       pv[41] = x[41];
976       pv[42] = x[42];
977       pv[43] = x[43];
978       pv[44] = x[44];
979       pv[45] = x[45];
980       pv[46] = x[46];
981       pv[47] = x[47];
982       pv[48] = x[48];
983       pv += 49;
984     }
985     /* invert diagonal block */
986     w = ba + 49 * diag_offset[i];
987     PetscCall(PetscKernel_A_gets_inverse_A_7(w, shift, allowzeropivot, &zeropivotdetected));
988     if (zeropivotdetected) C->factorerrortype = MAT_FACTOR_NUMERIC_ZEROPIVOT;
989   }
990 
991   PetscCall(PetscFree(rtmp));
992 
993   C->ops->solve          = MatSolve_SeqBAIJ_7_NaturalOrdering_inplace;
994   C->ops->solvetranspose = MatSolveTranspose_SeqBAIJ_7_NaturalOrdering_inplace;
995   C->assembled           = PETSC_TRUE;
996 
997   PetscCall(PetscLogFlops(1.333333333333 * 7 * 7 * 7 * b->mbs)); /* from inverting diagonal blocks */
998   PetscFunctionReturn(0);
999 }
1000 
1001 PetscErrorCode MatLUFactorNumeric_SeqBAIJ_7_NaturalOrdering(Mat B, Mat A, const MatFactorInfo *info) {
1002   Mat             C = B;
1003   Mat_SeqBAIJ    *a = (Mat_SeqBAIJ *)A->data, *b = (Mat_SeqBAIJ *)C->data;
1004   PetscInt        i, j, k, nz, nzL, row;
1005   const PetscInt  n = a->mbs, *ai = a->i, *aj = a->j, *bi = b->i, *bj = b->j;
1006   const PetscInt *ajtmp, *bjtmp, *bdiag = b->diag, *pj, bs2 = a->bs2;
1007   MatScalar      *rtmp, *pc, *mwork, *v, *pv, *aa = a->a;
1008   PetscInt        flg;
1009   PetscReal       shift = info->shiftamount;
1010   PetscBool       allowzeropivot, zeropivotdetected;
1011 
1012   PetscFunctionBegin;
1013   allowzeropivot = PetscNot(A->erroriffailure);
1014 
1015   /* generate work space needed by the factorization */
1016   PetscCall(PetscMalloc2(bs2 * n, &rtmp, bs2, &mwork));
1017   PetscCall(PetscArrayzero(rtmp, bs2 * n));
1018 
1019   for (i = 0; i < n; i++) {
1020     /* zero rtmp */
1021     /* L part */
1022     nz    = bi[i + 1] - bi[i];
1023     bjtmp = bj + bi[i];
1024     for (j = 0; j < nz; j++) { PetscCall(PetscArrayzero(rtmp + bs2 * bjtmp[j], bs2)); }
1025 
1026     /* U part */
1027     nz    = bdiag[i] - bdiag[i + 1];
1028     bjtmp = bj + bdiag[i + 1] + 1;
1029     for (j = 0; j < nz; j++) { PetscCall(PetscArrayzero(rtmp + bs2 * bjtmp[j], bs2)); }
1030 
1031     /* load in initial (unfactored row) */
1032     nz    = ai[i + 1] - ai[i];
1033     ajtmp = aj + ai[i];
1034     v     = aa + bs2 * ai[i];
1035     for (j = 0; j < nz; j++) { PetscCall(PetscArraycpy(rtmp + bs2 * ajtmp[j], v + bs2 * j, bs2)); }
1036 
1037     /* elimination */
1038     bjtmp = bj + bi[i];
1039     nzL   = bi[i + 1] - bi[i];
1040     for (k = 0; k < nzL; k++) {
1041       row = bjtmp[k];
1042       pc  = rtmp + bs2 * row;
1043       for (flg = 0, j = 0; j < bs2; j++) {
1044         if (pc[j] != 0.0) {
1045           flg = 1;
1046           break;
1047         }
1048       }
1049       if (flg) {
1050         pv = b->a + bs2 * bdiag[row];
1051         /* PetscKernel_A_gets_A_times_B(bs,pc,pv,mwork); *pc = *pc * (*pv); */
1052         PetscCall(PetscKernel_A_gets_A_times_B_7(pc, pv, mwork));
1053 
1054         pj = b->j + bdiag[row + 1] + 1; /* beginning of U(row,:) */
1055         pv = b->a + bs2 * (bdiag[row + 1] + 1);
1056         nz = bdiag[row] - bdiag[row + 1] - 1; /* num of entries inU(row,:), excluding diag */
1057         for (j = 0; j < nz; j++) {
1058           /* PetscKernel_A_gets_A_minus_B_times_C(bs,rtmp+bs2*pj[j],pc,pv+bs2*j); */
1059           /* rtmp+bs2*pj[j] = rtmp+bs2*pj[j] - (*pc)*(pv+bs2*j) */
1060           v = rtmp + bs2 * pj[j];
1061           PetscCall(PetscKernel_A_gets_A_minus_B_times_C_7(v, pc, pv));
1062           pv += bs2;
1063         }
1064         PetscCall(PetscLogFlops(686.0 * nz + 637)); /* flops = 2*bs^3*nz + 2*bs^3 - bs2) */
1065       }
1066     }
1067 
1068     /* finished row so stick it into b->a */
1069     /* L part */
1070     pv = b->a + bs2 * bi[i];
1071     pj = b->j + bi[i];
1072     nz = bi[i + 1] - bi[i];
1073     for (j = 0; j < nz; j++) { PetscCall(PetscArraycpy(pv + bs2 * j, rtmp + bs2 * pj[j], bs2)); }
1074 
1075     /* Mark diagonal and invert diagonal for simpler triangular solves */
1076     pv = b->a + bs2 * bdiag[i];
1077     pj = b->j + bdiag[i];
1078     PetscCall(PetscArraycpy(pv, rtmp + bs2 * pj[0], bs2));
1079     PetscCall(PetscKernel_A_gets_inverse_A_7(pv, shift, allowzeropivot, &zeropivotdetected));
1080     if (zeropivotdetected) C->factorerrortype = MAT_FACTOR_NUMERIC_ZEROPIVOT;
1081 
1082     /* U part */
1083     pv = b->a + bs2 * (bdiag[i + 1] + 1);
1084     pj = b->j + bdiag[i + 1] + 1;
1085     nz = bdiag[i] - bdiag[i + 1] - 1;
1086     for (j = 0; j < nz; j++) { PetscCall(PetscArraycpy(pv + bs2 * j, rtmp + bs2 * pj[j], bs2)); }
1087   }
1088   PetscCall(PetscFree2(rtmp, mwork));
1089 
1090   C->ops->solve          = MatSolve_SeqBAIJ_7_NaturalOrdering;
1091   C->ops->solvetranspose = MatSolveTranspose_SeqBAIJ_7_NaturalOrdering;
1092   C->assembled           = PETSC_TRUE;
1093 
1094   PetscCall(PetscLogFlops(1.333333333333 * 7 * 7 * 7 * n)); /* from inverting diagonal blocks */
1095   PetscFunctionReturn(0);
1096 }
1097