xref: /petsc/src/mat/impls/sbaij/seq/relax.h (revision eeffb40d691afbdd57a8091619e7ddd44ac5fdca)
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]; /* crash here running  './ex127 -n 1000' ??? */
47       vj   = v[j];
48       sum += vj * x[ibt];   /* (strict upper triangular part of A)*x  */
49 
50       vj = PetscConj(v[j]);
51       z[ibt] += vj * x1;    /* (strict lower triangular part of A)*x  */
52     }
53     z[i] += sum;
54     v    += nz;
55     ib   += nz;
56   }
57 
58   ierr = VecRestoreArray(xx,(PetscScalar**)&x);CHKERRQ(ierr);
59   ierr = VecRestoreArray(zz,&z);CHKERRQ(ierr);
60   ierr = PetscLogFlops(2.0*(2.0*a->nz - mbs) - mbs);CHKERRQ(ierr);
61   PetscFunctionReturn(0);
62 }
63 
64 #undef __FUNCT__
65 #define __FUNCT__ "MatMult_SeqSBAIJ_1"
66 PetscErrorCode PETSCMAP1(MatMult_SeqSBAIJ_1)(Mat A,Vec xx,Vec zz)
67 {
68   Mat_SeqSBAIJ         *a = (Mat_SeqSBAIJ*)A->data;
69   const PetscScalar    *x;
70   PetscScalar          *z,x1,sum;
71   const MatScalar      *v;
72   MatScalar            vj;
73   PetscErrorCode       ierr;
74   PetscInt             mbs=a->mbs,i,j,nz;
75   const PetscInt       *ai=a->i;
76 #if defined(USESHORT)
77   const unsigned short *ib=a->jshort;
78   unsigned short       ibt;
79 #else
80   const PetscInt       *ib=a->j;
81   PetscInt             ibt;
82 #endif
83 
84   PetscFunctionBegin;
85   ierr = VecSet(zz,0.0);CHKERRQ(ierr);
86   ierr = VecGetArray(xx,(PetscScalar**)&x);CHKERRQ(ierr);
87   ierr = VecGetArray(zz,&z);CHKERRQ(ierr);
88 
89   v  = a->a;
90   for (i=0; i<mbs; i++) {
91     nz   = ai[i+1] - ai[i];        /* length of i_th row of A */
92     x1   = x[i];
93     sum  = v[0]*x1;                /* diagonal term */
94     for (j=1; j<nz; j++) {
95       ibt = ib[j];
96       vj  = v[j];
97       z[ibt] += vj * x1;       /* (strict lower triangular part of A)*x  */
98       sum    += vj * x[ibt]; /* (strict upper triangular part of A)*x  */
99     }
100     z[i] += sum;
101     v    += nz;
102     ib   += nz;
103   }
104 
105   ierr = VecRestoreArray(xx,(PetscScalar**)&x);CHKERRQ(ierr);
106   ierr = VecRestoreArray(zz,&z);CHKERRQ(ierr);
107   ierr = PetscLogFlops(2.0*(2.0*a->nz - mbs) - mbs);CHKERRQ(ierr);
108   PetscFunctionReturn(0);
109 }
110 
111 #undef __FUNCT__
112 #define __FUNCT__ "MatSOR_SeqSBAIJ"
113 PetscErrorCode PETSCMAP1(MatSOR_SeqSBAIJ)(Mat A,Vec bb,PetscReal omega,MatSORType flag,PetscReal fshift,PetscInt its,PetscInt lits,Vec xx)
114 {
115   Mat_SeqSBAIJ         *a = (Mat_SeqSBAIJ*)A->data;
116   const MatScalar      *aa=a->a,*v,*v1,*aidiag;
117   PetscScalar          *x,*t,sum;
118   const PetscScalar    *b;
119   MatScalar            tmp;
120   PetscErrorCode       ierr;
121   PetscInt             m=a->mbs,bs=A->rmap->bs,j;
122   const PetscInt       *ai=a->i;
123 #if defined(USESHORT)
124   const unsigned short *aj=a->jshort,*vj,*vj1;
125 #else
126   const PetscInt       *aj=a->j,*vj,*vj1;
127 #endif
128   PetscInt             nz,nz1,i;
129 
130   PetscFunctionBegin;
131   if (flag & SOR_EISENSTAT) SETERRQ(PETSC_ERR_SUP,"No support yet for Eisenstat");
132 
133   its = its*lits;
134   if (its <= 0) SETERRQ2(PETSC_ERR_ARG_WRONG,"Relaxation requires global its %D and local its %D both positive",its,lits);
135 
136   if (bs > 1) SETERRQ(PETSC_ERR_SUP,"SSOR for block size > 1 is not yet implemented");
137 
138   ierr = VecGetArray(xx,&x);CHKERRQ(ierr);
139   if (xx != bb) {
140     ierr = VecGetArray(bb,(PetscScalar**)&b);CHKERRQ(ierr);
141   } else {
142     b = x;
143   }
144 
145   if (!a->idiagvalid) {
146     if (!a->idiag) {
147       ierr     = PetscMalloc(m*sizeof(PetscScalar),&a->idiag);CHKERRQ(ierr);
148     }
149     for (i=0; i<a->mbs; i++) a->idiag[i] = 1.0/a->a[a->i[i]];
150     a->idiagvalid = PETSC_TRUE;
151   }
152 
153   if (!a->sor_work) {
154     ierr = PetscMalloc(m*sizeof(PetscScalar),&a->sor_work);CHKERRQ(ierr);
155   }
156   t = a->sor_work;
157 
158   aidiag = a->idiag;
159 
160   if (flag == SOR_APPLY_UPPER) {
161     /* apply (U + D/omega) to the vector */
162     PetscScalar d;
163     for (i=0; i<m; i++) {
164       d    = fshift + aa[ai[i]];
165       nz   = ai[i+1] - ai[i] - 1;
166       vj   = aj + ai[i] + 1;
167       v    = aa + ai[i] + 1;
168       sum  = b[i]*d/omega;
169       PetscSparseDensePlusDot(sum,b,v,vj,nz);
170       x[i] = sum;
171     }
172     ierr = PetscLogFlops(a->nz);CHKERRQ(ierr);
173   }
174 
175   if (flag & SOR_ZERO_INITIAL_GUESS) {
176     if (flag & SOR_FORWARD_SWEEP || flag & SOR_LOCAL_FORWARD_SWEEP){
177       ierr = PetscMemcpy(t,b,m*sizeof(PetscScalar));CHKERRQ(ierr);
178 
179       v  = aa + 1;
180       vj = aj + 1;
181       for (i=0; i<m; i++){
182         nz = ai[i+1] - ai[i] - 1;
183         tmp = - (x[i] = omega*t[i]*aidiag[i]);
184         for (j=0; j<nz; j++) {
185           t[vj[j]] += tmp*v[j];
186         }
187         v  += nz + 1;
188         vj += nz + 1;
189       }
190       ierr = PetscLogFlops(2*a->nz);CHKERRQ(ierr);
191     }
192 
193     if (flag & SOR_BACKWARD_SWEEP || flag & SOR_LOCAL_BACKWARD_SWEEP){
194       int nz2;
195       if (!(flag & SOR_FORWARD_SWEEP || flag & SOR_LOCAL_FORWARD_SWEEP)){
196 #if defined(PETSC_USE_BACKWARD_LOOP)
197 	v  = aa + ai[m] - 1;
198 	vj = aj + ai[m] - 1;
199 	for (i=m-1; i>=0; i--){
200           sum = b[i];
201 	  nz  = ai[i+1] - ai[i] - 1;
202           {PetscInt __i;for(__i=0;__i<nz;__i++) sum -= v[-__i] * x[vj[-__i]];}
203 #else
204 	v  = aa + ai[m-1] + 1;
205 	vj = aj + ai[m-1] + 1;
206 	nz = 0;
207 	for (i=m-1; i>=0; i--){
208           sum = b[i];
209 	  nz2 = ai[i] - ai[i-1] - 1;
210 	  PETSC_Prefetch(v-nz2-1,0,1);
211 	  PETSC_Prefetch(vj-nz2-1,0,1);
212 	  PetscSparseDenseMinusDot(sum,x,v,vj,nz);
213           nz   = nz2;
214 #endif
215           x[i] = omega*sum*aidiag[i];
216 	  v  -= nz + 1;
217 	  vj -= nz + 1;
218 	}
219 	ierr = PetscLogFlops(2*a->nz);CHKERRQ(ierr);
220       } else {
221         v  = aa + ai[m-1] + 1;
222 	vj = aj + ai[m-1] + 1;
223 	nz = 0;
224 	for (i=m-1; i>=0; i--){
225           sum = t[i];
226 	  nz2 = ai[i] - ai[i-1] - 1;
227 	  PETSC_Prefetch(v-nz2-1,0,1);
228 	  PETSC_Prefetch(vj-nz2-1,0,1);
229 	  PetscSparseDenseMinusDot(sum,x,v,vj,nz);
230           x[i] = (1-omega)*x[i] + omega*sum*aidiag[i];
231 	  nz  = nz2;
232 	  v  -= nz + 1;
233 	  vj -= nz + 1;
234 	}
235 	ierr = PetscLogFlops(2*a->nz);CHKERRQ(ierr);
236       }
237     }
238     its--;
239   }
240 
241   while (its--) {
242     /*
243        forward sweep:
244        for i=0,...,m-1:
245          sum[i] = (b[i] - U(i,:)x )/d[i];
246          x[i]   = (1-omega)x[i] + omega*sum[i];
247          b      = b - x[i]*U^T(i,:);
248 
249     */
250     if (flag & SOR_FORWARD_SWEEP || flag & SOR_LOCAL_FORWARD_SWEEP){
251       ierr = PetscMemcpy(t,b,m*sizeof(PetscScalar));CHKERRQ(ierr);
252 
253       for (i=0; i<m; i++){
254         v  = aa + ai[i] + 1; v1=v;
255         vj = aj + ai[i] + 1; vj1=vj;
256         nz = ai[i+1] - ai[i] - 1; nz1=nz;
257         sum = t[i];
258         ierr = PetscLogFlops(4.0*nz-2);CHKERRQ(ierr);
259         while (nz1--) sum -= (*v1++)*x[*vj1++];
260         x[i] = (1-omega)*x[i] + omega*sum*aidiag[i];
261         while (nz--) t[*vj++] -= x[i]*(*v++);
262       }
263     }
264 
265     if (flag & SOR_BACKWARD_SWEEP || flag & SOR_LOCAL_BACKWARD_SWEEP){
266       /*
267        backward sweep:
268        b = b - x[i]*U^T(i,:), i=0,...,n-2
269        for i=m-1,...,0:
270          sum[i] = (b[i] - U(i,:)x )/d[i];
271          x[i]   = (1-omega)x[i] + omega*sum[i];
272       */
273       /* if there was a forward sweep done above then I thing the next two for loops are not needed */
274       ierr = PetscMemcpy(t,b,m*sizeof(PetscScalar));CHKERRQ(ierr);
275 
276       for (i=0; i<m-1; i++){  /* update rhs */
277         v  = aa + ai[i] + 1;
278         vj = aj + ai[i] + 1;
279         nz = ai[i+1] - ai[i] - 1;
280         ierr = PetscLogFlops(2.0*nz-1);CHKERRQ(ierr);
281         while (nz--) t[*vj++] -= x[i]*(*v++);
282       }
283       for (i=m-1; i>=0; i--){
284         v  = aa + ai[i] + 1;
285         vj = aj + ai[i] + 1;
286         nz = ai[i+1] - ai[i] - 1;
287         ierr = PetscLogFlops(2.0*nz-1);CHKERRQ(ierr);
288         sum = t[i];
289         while (nz--) sum -= x[*vj++]*(*v++);
290         x[i] =   (1-omega)*x[i] + omega*sum*aidiag[i];
291       }
292     }
293   }
294 
295   ierr = VecRestoreArray(xx,&x);CHKERRQ(ierr);
296   if (bb != xx) {
297     ierr = VecRestoreArray(bb,(PetscScalar**)&b);CHKERRQ(ierr);
298   }
299   PetscFunctionReturn(0);
300 }
301