xref: /petsc/src/mat/impls/sbaij/seq/relax.h (revision 753ebd1d069d7a4e86ed47ccb83df941bd1fb5db)
1 
2 /*
3     This is included by sbaij.c to generate unsigned short and regular versions of these two functions
4 */
5 #undef  USHORT
6 #if defined(USESHORT)
7 #define USHORT _ushort
8 #else
9 #define USHORT
10 #endif
11 #define PETSCMAP1_a(a,b)  a ## b
12 #define PETSCMAP1_b(a,b)  PETSCMAP1_a(a,b)
13 #define PETSCMAP1(a)      PETSCMAP1_b(a,USHORT)
14 
15 #undef __FUNCT__
16 #define __FUNCT__ "MatMult_SeqSBAIJ_1_Hermitian"
17 PetscErrorCode PETSCMAP1(MatMult_SeqSBAIJ_1_Hermitian)(Mat A,Vec xx,Vec zz)
18 {
19   Mat_SeqSBAIJ         *a = (Mat_SeqSBAIJ*)A->data;
20   const PetscScalar    *x;
21   PetscScalar          *z,x1,sum;
22   const MatScalar      *v;
23   MatScalar            vj;
24   PetscErrorCode       ierr;
25   PetscInt             mbs=a->mbs,i,j,nz;
26   const PetscInt       *ai=a->i;
27 #if defined(USESHORT)
28   const unsigned short *ib=a->jshort;
29   unsigned short       ibt;
30 #else
31   const PetscInt       *ib=a->j;
32   PetscInt             ibt;
33 #endif
34 
35   PetscFunctionBegin;
36   ierr = VecSet(zz,0.0);CHKERRQ(ierr);
37   ierr = VecGetArray(xx,(PetscScalar**)&x);CHKERRQ(ierr);
38   ierr = VecGetArray(zz,&z);CHKERRQ(ierr);
39 
40   v  = a->a;
41   for (i=0; i<mbs; i++) {
42     nz   = ai[i+1] - ai[i];  /* length of i_th row of A */
43     x1   = x[i];
44     sum  = v[0]*x1;          /* diagonal term */
45     for (j=1; j<nz; j++) {
46       ibt  = ib[j];
47       vj   = v[j];
48       sum += vj * x[ibt];   /* (strict upper triangular part of A)*x  */
49       z[ibt] += PetscConj(v[j]) * x1;    /* (strict lower triangular part of A)*x  */
50     }
51     z[i] += sum;
52     v    += nz;
53     ib   += nz;
54   }
55 
56   ierr = VecRestoreArray(xx,(PetscScalar**)&x);CHKERRQ(ierr);
57   ierr = VecRestoreArray(zz,&z);CHKERRQ(ierr);
58   ierr = PetscLogFlops(2.0*(2.0*a->nz - mbs) - mbs);CHKERRQ(ierr);
59   PetscFunctionReturn(0);
60 }
61 
62 #undef __FUNCT__
63 #define __FUNCT__ "MatMult_SeqSBAIJ_1"
64 PetscErrorCode PETSCMAP1(MatMult_SeqSBAIJ_1)(Mat A,Vec xx,Vec zz)
65 {
66   Mat_SeqSBAIJ         *a = (Mat_SeqSBAIJ*)A->data;
67   const PetscScalar    *x;
68   PetscScalar          *z,x1,sum;
69   const MatScalar      *v;
70   MatScalar            vj;
71   PetscErrorCode       ierr;
72   PetscInt             mbs=a->mbs,i,j,nz;
73   const PetscInt       *ai=a->i;
74 #if defined(USESHORT)
75   const unsigned short *ib=a->jshort;
76   unsigned short       ibt;
77 #else
78   const PetscInt       *ib=a->j;
79   PetscInt             ibt;
80 #endif
81 
82   PetscFunctionBegin;
83   ierr = VecSet(zz,0.0);CHKERRQ(ierr);
84   ierr = VecGetArray(xx,(PetscScalar**)&x);CHKERRQ(ierr);
85   ierr = VecGetArray(zz,&z);CHKERRQ(ierr);
86 
87   v  = a->a;
88   for (i=0; i<mbs; i++) {
89     nz   = ai[i+1] - ai[i];        /* length of i_th row of A */
90     x1   = x[i];
91     sum  = v[0]*x1;                /* diagonal term */
92     for (j=1; j<nz; j++) {
93       ibt = ib[j];
94       vj  = v[j];
95       z[ibt] += vj * x1;       /* (strict lower triangular part of A)*x  */
96       sum    += vj * x[ibt]; /* (strict upper triangular part of A)*x  */
97     }
98     z[i] += sum;
99     v    += nz;
100     ib   += nz;
101   }
102 
103   ierr = VecRestoreArray(xx,(PetscScalar**)&x);CHKERRQ(ierr);
104   ierr = VecRestoreArray(zz,&z);CHKERRQ(ierr);
105   ierr = PetscLogFlops(2.0*(2.0*a->nz - mbs) - mbs);CHKERRQ(ierr);
106   PetscFunctionReturn(0);
107 }
108 
109 #undef __FUNCT__
110 #define __FUNCT__ "MatSOR_SeqSBAIJ"
111 PetscErrorCode PETSCMAP1(MatSOR_SeqSBAIJ)(Mat A,Vec bb,PetscReal omega,MatSORType flag,PetscReal fshift,PetscInt its,PetscInt lits,Vec xx)
112 {
113   Mat_SeqSBAIJ         *a = (Mat_SeqSBAIJ*)A->data;
114   const MatScalar      *aa=a->a,*v,*v1,*aidiag;
115   PetscScalar          *x,*t,sum;
116   const PetscScalar    *b;
117   MatScalar            tmp;
118   PetscErrorCode       ierr;
119   PetscInt             m=a->mbs,bs=A->rmap->bs,j;
120   const PetscInt       *ai=a->i;
121 #if defined(USESHORT)
122   const unsigned short *aj=a->jshort,*vj,*vj1;
123 #else
124   const PetscInt       *aj=a->j,*vj,*vj1;
125 #endif
126   PetscInt             nz,nz1,i;
127 
128   PetscFunctionBegin;
129   if (flag & SOR_EISENSTAT) SETERRQ(PETSC_ERR_SUP,"No support yet for Eisenstat");
130 
131   its = its*lits;
132   if (its <= 0) SETERRQ2(PETSC_ERR_ARG_WRONG,"Relaxation requires global its %D and local its %D both positive",its,lits);
133 
134   if (bs > 1) SETERRQ(PETSC_ERR_SUP,"SSOR for block size > 1 is not yet implemented");
135 
136   ierr = VecGetArray(xx,&x);CHKERRQ(ierr);
137   if (xx != bb) {
138     ierr = VecGetArray(bb,(PetscScalar**)&b);CHKERRQ(ierr);
139   } else {
140     b = x;
141   }
142 
143   if (!a->idiagvalid) {
144     if (!a->idiag) {
145       ierr     = PetscMalloc(m*sizeof(PetscScalar),&a->idiag);CHKERRQ(ierr);
146     }
147     for (i=0; i<a->mbs; i++) a->idiag[i] = 1.0/a->a[a->i[i]];
148     a->idiagvalid = PETSC_TRUE;
149   }
150 
151   if (!a->sor_work) {
152     ierr = PetscMalloc(m*sizeof(PetscScalar),&a->sor_work);CHKERRQ(ierr);
153   }
154   t = a->sor_work;
155 
156   aidiag = a->idiag;
157 
158   if (flag == SOR_APPLY_UPPER) {
159     /* apply (U + D/omega) to the vector */
160     PetscScalar d;
161     for (i=0; i<m; i++) {
162       d    = fshift + aa[ai[i]];
163       nz   = ai[i+1] - ai[i] - 1;
164       vj   = aj + ai[i] + 1;
165       v    = aa + ai[i] + 1;
166       sum  = b[i]*d/omega;
167       PetscSparseDensePlusDot(sum,b,v,vj,nz);
168       x[i] = sum;
169     }
170     ierr = PetscLogFlops(a->nz);CHKERRQ(ierr);
171   }
172 
173   if (flag & SOR_ZERO_INITIAL_GUESS) {
174     if (flag & SOR_FORWARD_SWEEP || flag & SOR_LOCAL_FORWARD_SWEEP){
175       ierr = PetscMemcpy(t,b,m*sizeof(PetscScalar));CHKERRQ(ierr);
176 
177       v  = aa + 1;
178       vj = aj + 1;
179       for (i=0; i<m; i++){
180         nz = ai[i+1] - ai[i] - 1;
181         tmp = - (x[i] = omega*t[i]*aidiag[i]);
182         for (j=0; j<nz; j++) {
183           t[vj[j]] += tmp*v[j];
184         }
185         v  += nz + 1;
186         vj += nz + 1;
187       }
188       ierr = PetscLogFlops(2*a->nz);CHKERRQ(ierr);
189     }
190 
191     if (flag & SOR_BACKWARD_SWEEP || flag & SOR_LOCAL_BACKWARD_SWEEP){
192       int nz2;
193       if (!(flag & SOR_FORWARD_SWEEP || flag & SOR_LOCAL_FORWARD_SWEEP)){
194 #if defined(PETSC_USE_BACKWARD_LOOP)
195 	v  = aa + ai[m] - 1;
196 	vj = aj + ai[m] - 1;
197 	for (i=m-1; i>=0; i--){
198           sum = b[i];
199 	  nz  = ai[i+1] - ai[i] - 1;
200           {PetscInt __i;for(__i=0;__i<nz;__i++) sum -= v[-__i] * x[vj[-__i]];}
201 #else
202 	v  = aa + ai[m-1] + 1;
203 	vj = aj + ai[m-1] + 1;
204 	nz = 0;
205 	for (i=m-1; i>=0; i--){
206           sum = b[i];
207 	  nz2 = ai[i] - ai[i-1] - 1;
208 	  PETSC_Prefetch(v-nz2-1,0,1);
209 	  PETSC_Prefetch(vj-nz2-1,0,1);
210 	  PetscSparseDenseMinusDot(sum,x,v,vj,nz);
211           nz   = nz2;
212 #endif
213           x[i] = omega*sum*aidiag[i];
214 	  v  -= nz + 1;
215 	  vj -= nz + 1;
216 	}
217 	ierr = PetscLogFlops(2*a->nz);CHKERRQ(ierr);
218       } else {
219         v  = aa + ai[m-1] + 1;
220 	vj = aj + ai[m-1] + 1;
221 	nz = 0;
222 	for (i=m-1; i>=0; i--){
223           sum = t[i];
224 	  nz2 = ai[i] - ai[i-1] - 1;
225 	  PETSC_Prefetch(v-nz2-1,0,1);
226 	  PETSC_Prefetch(vj-nz2-1,0,1);
227 	  PetscSparseDenseMinusDot(sum,x,v,vj,nz);
228           x[i] = (1-omega)*x[i] + omega*sum*aidiag[i];
229 	  nz  = nz2;
230 	  v  -= nz + 1;
231 	  vj -= nz + 1;
232 	}
233 	ierr = PetscLogFlops(2*a->nz);CHKERRQ(ierr);
234       }
235     }
236     its--;
237   }
238 
239   while (its--) {
240     /*
241        forward sweep:
242        for i=0,...,m-1:
243          sum[i] = (b[i] - U(i,:)x )/d[i];
244          x[i]   = (1-omega)x[i] + omega*sum[i];
245          b      = b - x[i]*U^T(i,:);
246 
247     */
248     if (flag & SOR_FORWARD_SWEEP || flag & SOR_LOCAL_FORWARD_SWEEP){
249       ierr = PetscMemcpy(t,b,m*sizeof(PetscScalar));CHKERRQ(ierr);
250 
251       for (i=0; i<m; i++){
252         v  = aa + ai[i] + 1; v1=v;
253         vj = aj + ai[i] + 1; vj1=vj;
254         nz = ai[i+1] - ai[i] - 1; nz1=nz;
255         sum = t[i];
256         ierr = PetscLogFlops(4.0*nz-2);CHKERRQ(ierr);
257         while (nz1--) sum -= (*v1++)*x[*vj1++];
258         x[i] = (1-omega)*x[i] + omega*sum*aidiag[i];
259         while (nz--) t[*vj++] -= x[i]*(*v++);
260       }
261     }
262 
263     if (flag & SOR_BACKWARD_SWEEP || flag & SOR_LOCAL_BACKWARD_SWEEP){
264       /*
265        backward sweep:
266        b = b - x[i]*U^T(i,:), i=0,...,n-2
267        for i=m-1,...,0:
268          sum[i] = (b[i] - U(i,:)x )/d[i];
269          x[i]   = (1-omega)x[i] + omega*sum[i];
270       */
271       /* if there was a forward sweep done above then I thing the next two for loops are not needed */
272       ierr = PetscMemcpy(t,b,m*sizeof(PetscScalar));CHKERRQ(ierr);
273 
274       for (i=0; i<m-1; i++){  /* update rhs */
275         v  = aa + ai[i] + 1;
276         vj = aj + ai[i] + 1;
277         nz = ai[i+1] - ai[i] - 1;
278         ierr = PetscLogFlops(2.0*nz-1);CHKERRQ(ierr);
279         while (nz--) t[*vj++] -= x[i]*(*v++);
280       }
281       for (i=m-1; i>=0; i--){
282         v  = aa + ai[i] + 1;
283         vj = aj + ai[i] + 1;
284         nz = ai[i+1] - ai[i] - 1;
285         ierr = PetscLogFlops(2.0*nz-1);CHKERRQ(ierr);
286         sum = t[i];
287         while (nz--) sum -= x[*vj++]*(*v++);
288         x[i] =   (1-omega)*x[i] + omega*sum*aidiag[i];
289       }
290     }
291   }
292 
293   ierr = VecRestoreArray(xx,&x);CHKERRQ(ierr);
294   if (bb != xx) {
295     ierr = VecRestoreArray(bb,(PetscScalar**)&b);CHKERRQ(ierr);
296   }
297   PetscFunctionReturn(0);
298 }
299