xref: /petsc/src/mat/impls/sbaij/seq/sbaijfact5.c (revision 2205254efee3a00a594e5e2a3a70f74dcb40bc03)
1 
2 #include <../src/mat/impls/sbaij/seq/sbaij.h>
3 #include <../src/mat/blockinvert.h>
4 
5 /*
6       Version for when blocks are 4 by 4 Using natural ordering
7 */
8 #undef __FUNCT__
9 #define __FUNCT__ "MatCholeskyFactorNumeric_SeqSBAIJ_4_NaturalOrdering"
10 PetscErrorCode MatCholeskyFactorNumeric_SeqSBAIJ_4_NaturalOrdering(Mat C,Mat A,const MatFactorInfo *info)
11 {
12   Mat_SeqSBAIJ   *a = (Mat_SeqSBAIJ*)A->data,*b = (Mat_SeqSBAIJ *)C->data;
13   PetscErrorCode ierr;
14   PetscInt       i,j,mbs=a->mbs,*bi=b->i,*bj=b->j;
15   PetscInt       *ai,*aj,k,k1,jmin,jmax,*jl,*il,vj,nexti,ili;
16   MatScalar      *ba = b->a,*aa,*ap,*dk,*uik;
17   MatScalar      *u,*diag,*rtmp,*rtmp_ptr;
18   PetscBool      pivotinblocks = b->pivotinblocks;
19   PetscReal      shift = info->shiftamount;
20 
21   PetscFunctionBegin;
22   /* initialization */
23   ierr = PetscMalloc(16*mbs*sizeof(MatScalar),&rtmp);CHKERRQ(ierr);
24   ierr = PetscMemzero(rtmp,16*mbs*sizeof(MatScalar));CHKERRQ(ierr);
25   ierr = PetscMalloc2(mbs,PetscInt,&il,mbs,PetscInt,&jl);CHKERRQ(ierr);
26   for (i=0; i<mbs; i++) {
27     jl[i] = mbs; il[0] = 0;
28   }
29   ierr = PetscMalloc2(16,MatScalar,&dk,16,MatScalar,&uik);CHKERRQ(ierr);
30   ai = a->i; aj = a->j; aa = a->a;
31 
32   /* for each row k */
33   for (k = 0; k<mbs; k++) {
34 
35     /*initialize k-th row with elements nonzero in row k of A */
36     jmin = ai[k]; jmax = ai[k+1];
37     if (jmin < jmax) {
38       ap = aa + jmin*16;
39       for (j = jmin; j < jmax; j++) {
40         vj = aj[j];         /* block col. index */
41         rtmp_ptr = rtmp + vj*16;
42         for (i=0; i<16; i++) *rtmp_ptr++ = *ap++;
43       }
44     }
45 
46     /* modify k-th row by adding in those rows i with U(i,k) != 0 */
47     ierr = PetscMemcpy(dk,rtmp+k*16,16*sizeof(MatScalar));CHKERRQ(ierr);
48     i = jl[k]; /* first row to be added to k_th row  */
49 
50     while (i < mbs) {
51       nexti = jl[i]; /* next row to be added to k_th row */
52 
53       /* compute multiplier */
54       ili = il[i];  /* index of first nonzero element in U(i,k:bms-1) */
55 
56       /* uik = -inv(Di)*U_bar(i,k) */
57       diag = ba + i*16;
58       u    = ba + ili*16;
59 
60       uik[0] = -(diag[0]*u[0] + diag[4]*u[1] + diag[8]*u[2] + diag[12]*u[3]);
61       uik[1] = -(diag[1]*u[0] + diag[5]*u[1] + diag[9]*u[2] + diag[13]*u[3]);
62       uik[2] = -(diag[2]*u[0] + diag[6]*u[1] + diag[10]*u[2]+ diag[14]*u[3]);
63       uik[3] = -(diag[3]*u[0] + diag[7]*u[1] + diag[11]*u[2]+ diag[15]*u[3]);
64 
65       uik[4] = -(diag[0]*u[4] + diag[4]*u[5] + diag[8]*u[6] + diag[12]*u[7]);
66       uik[5] = -(diag[1]*u[4] + diag[5]*u[5] + diag[9]*u[6] + diag[13]*u[7]);
67       uik[6] = -(diag[2]*u[4] + diag[6]*u[5] + diag[10]*u[6]+ diag[14]*u[7]);
68       uik[7] = -(diag[3]*u[4] + diag[7]*u[5] + diag[11]*u[6]+ diag[15]*u[7]);
69 
70       uik[8] = -(diag[0]*u[8] + diag[4]*u[9] + diag[8]*u[10] + diag[12]*u[11]);
71       uik[9] = -(diag[1]*u[8] + diag[5]*u[9] + diag[9]*u[10] + diag[13]*u[11]);
72       uik[10]= -(diag[2]*u[8] + diag[6]*u[9] + diag[10]*u[10]+ diag[14]*u[11]);
73       uik[11]= -(diag[3]*u[8] + diag[7]*u[9] + diag[11]*u[10]+ diag[15]*u[11]);
74 
75       uik[12]= -(diag[0]*u[12] + diag[4]*u[13] + diag[8]*u[14] + diag[12]*u[15]);
76       uik[13]= -(diag[1]*u[12] + diag[5]*u[13] + diag[9]*u[14] + diag[13]*u[15]);
77       uik[14]= -(diag[2]*u[12] + diag[6]*u[13] + diag[10]*u[14]+ diag[14]*u[15]);
78       uik[15]= -(diag[3]*u[12] + diag[7]*u[13] + diag[11]*u[14]+ diag[15]*u[15]);
79 
80       /* update D(k) += -U(i,k)^T * U_bar(i,k) */
81       dk[0] += uik[0]*u[0] + uik[1]*u[1] + uik[2]*u[2] + uik[3]*u[3];
82       dk[1] += uik[4]*u[0] + uik[5]*u[1] + uik[6]*u[2] + uik[7]*u[3];
83       dk[2] += uik[8]*u[0] + uik[9]*u[1] + uik[10]*u[2]+ uik[11]*u[3];
84       dk[3] += uik[12]*u[0]+ uik[13]*u[1]+ uik[14]*u[2]+ uik[15]*u[3];
85 
86       dk[4] += uik[0]*u[4] + uik[1]*u[5] + uik[2]*u[6] + uik[3]*u[7];
87       dk[5] += uik[4]*u[4] + uik[5]*u[5] + uik[6]*u[6] + uik[7]*u[7];
88       dk[6] += uik[8]*u[4] + uik[9]*u[5] + uik[10]*u[6]+ uik[11]*u[7];
89       dk[7] += uik[12]*u[4]+ uik[13]*u[5]+ uik[14]*u[6]+ uik[15]*u[7];
90 
91       dk[8] += uik[0]*u[8] + uik[1]*u[9] + uik[2]*u[10] + uik[3]*u[11];
92       dk[9] += uik[4]*u[8] + uik[5]*u[9] + uik[6]*u[10] + uik[7]*u[11];
93       dk[10]+= uik[8]*u[8] + uik[9]*u[9] + uik[10]*u[10]+ uik[11]*u[11];
94       dk[11]+= uik[12]*u[8]+ uik[13]*u[9]+ uik[14]*u[10]+ uik[15]*u[11];
95 
96       dk[12]+= uik[0]*u[12] + uik[1]*u[13] + uik[2]*u[14] + uik[3]*u[15];
97       dk[13]+= uik[4]*u[12] + uik[5]*u[13] + uik[6]*u[14] + uik[7]*u[15];
98       dk[14]+= uik[8]*u[12] + uik[9]*u[13] + uik[10]*u[14]+ uik[11]*u[15];
99       dk[15]+= uik[12]*u[12]+ uik[13]*u[13]+ uik[14]*u[14]+ uik[15]*u[15];
100 
101       ierr = PetscLogFlops(64.0*4.0);CHKERRQ(ierr);
102 
103       /* update -U(i,k) */
104       ierr = PetscMemcpy(ba+ili*16,uik,16*sizeof(MatScalar));CHKERRQ(ierr);
105 
106       /* add multiple of row i to k-th row ... */
107       jmin = ili + 1; jmax = bi[i+1];
108       if (jmin < jmax) {
109         for (j=jmin; j<jmax; j++) {
110           /* rtmp += -U(i,k)^T * U_bar(i,j) */
111           rtmp_ptr = rtmp + bj[j]*16;
112           u = ba + j*16;
113           rtmp_ptr[0] += uik[0]*u[0] + uik[1]*u[1] + uik[2]*u[2] + uik[3]*u[3];
114           rtmp_ptr[1] += uik[4]*u[0] + uik[5]*u[1] + uik[6]*u[2] + uik[7]*u[3];
115           rtmp_ptr[2] += uik[8]*u[0] + uik[9]*u[1] + uik[10]*u[2]+ uik[11]*u[3];
116           rtmp_ptr[3] += uik[12]*u[0]+ uik[13]*u[1]+ uik[14]*u[2]+ uik[15]*u[3];
117 
118           rtmp_ptr[4] += uik[0]*u[4] + uik[1]*u[5] + uik[2]*u[6] + uik[3]*u[7];
119           rtmp_ptr[5] += uik[4]*u[4] + uik[5]*u[5] + uik[6]*u[6] + uik[7]*u[7];
120           rtmp_ptr[6] += uik[8]*u[4] + uik[9]*u[5] + uik[10]*u[6]+ uik[11]*u[7];
121           rtmp_ptr[7] += uik[12]*u[4]+ uik[13]*u[5]+ uik[14]*u[6]+ uik[15]*u[7];
122 
123           rtmp_ptr[8] += uik[0]*u[8] + uik[1]*u[9] + uik[2]*u[10] + uik[3]*u[11];
124           rtmp_ptr[9] += uik[4]*u[8] + uik[5]*u[9] + uik[6]*u[10] + uik[7]*u[11];
125           rtmp_ptr[10]+= uik[8]*u[8] + uik[9]*u[9] + uik[10]*u[10]+ uik[11]*u[11];
126           rtmp_ptr[11]+= uik[12]*u[8]+ uik[13]*u[9]+ uik[14]*u[10]+ uik[15]*u[11];
127 
128           rtmp_ptr[12]+= uik[0]*u[12] + uik[1]*u[13] + uik[2]*u[14] + uik[3]*u[15];
129           rtmp_ptr[13]+= uik[4]*u[12] + uik[5]*u[13] + uik[6]*u[14] + uik[7]*u[15];
130           rtmp_ptr[14]+= uik[8]*u[12] + uik[9]*u[13] + uik[10]*u[14]+ uik[11]*u[15];
131           rtmp_ptr[15]+= uik[12]*u[12]+ uik[13]*u[13]+ uik[14]*u[14]+ uik[15]*u[15];
132         }
133         ierr = PetscLogFlops(2.0*64.0*(jmax-jmin));CHKERRQ(ierr);
134 
135         /* ... add i to row list for next nonzero entry */
136         il[i] = jmin;             /* update il(i) in column k+1, ... mbs-1 */
137         j     = bj[jmin];
138         jl[i] = jl[j]; jl[j] = i; /* update jl */
139       }
140       i = nexti;
141     }
142 
143     /* save nonzero entries in k-th row of U ... */
144 
145     /* invert diagonal block */
146     diag = ba+k*16;
147     ierr = PetscMemcpy(diag,dk,16*sizeof(MatScalar));CHKERRQ(ierr);
148     if (pivotinblocks) {
149       ierr = PetscKernel_A_gets_inverse_A_4(diag,shift);CHKERRQ(ierr);
150     } else {
151       ierr = PetscKernel_A_gets_inverse_A_4_nopivot(diag);CHKERRQ(ierr);
152     }
153 
154     jmin = bi[k]; jmax = bi[k+1];
155     if (jmin < jmax) {
156       for (j=jmin; j<jmax; j++) {
157          vj = bj[j];           /* block col. index of U */
158          u   = ba + j*16;
159          rtmp_ptr = rtmp + vj*16;
160          for (k1=0; k1<16; k1++) {
161            *u++        = *rtmp_ptr;
162            *rtmp_ptr++ = 0.0;
163          }
164       }
165 
166       /* ... add k to row list for first nonzero entry in k-th row */
167       il[k] = jmin;
168       i     = bj[jmin];
169       jl[k] = jl[i]; jl[i] = k;
170     }
171   }
172 
173   ierr = PetscFree(rtmp);CHKERRQ(ierr);
174   ierr = PetscFree2(il,jl);CHKERRQ(ierr);
175   ierr = PetscFree2(dk,uik);CHKERRQ(ierr);
176 
177   C->ops->solve          = MatSolve_SeqSBAIJ_4_NaturalOrdering_inplace;
178   C->ops->solvetranspose = MatSolve_SeqSBAIJ_4_NaturalOrdering_inplace;
179   C->ops->forwardsolve   = MatForwardSolve_SeqSBAIJ_4_NaturalOrdering_inplace;
180   C->ops->backwardsolve  = MatBackwardSolve_SeqSBAIJ_4_NaturalOrdering_inplace;
181 
182   C->assembled = PETSC_TRUE;
183   C->preallocated = PETSC_TRUE;
184   ierr = PetscLogFlops(1.3333*64*b->mbs);CHKERRQ(ierr); /* from inverting diagonal blocks */
185   PetscFunctionReturn(0);
186 }
187