xref: /petsc/src/mat/impls/sbaij/seq/relax.h (revision db81a22fc6a71a2fb932d0d72fd0961297e5f61a)
1 
2 /*
3     This is included by sbaij.c to generate unsigned short and regular versions of these two functions
4 */
5 #undef __FUNCT__
6 #define __FUNCT__ "MatMult_SeqSBAIJ_1_Hermitian"
7 #if defined(USESHORT)
8 PetscErrorCode MatMult_SeqSBAIJ_1_Hermitian_ushort(Mat A,Vec xx,Vec zz)
9 #else
10 PetscErrorCode MatMult_SeqSBAIJ_1_Hermitian(Mat A,Vec xx,Vec zz)
11 #endif
12 {
13   Mat_SeqSBAIJ         *a = (Mat_SeqSBAIJ*)A->data;
14   const PetscScalar    *x;
15   PetscScalar          *z,x1,sum;
16   const MatScalar      *v;
17   MatScalar            vj;
18   PetscErrorCode       ierr;
19   PetscInt             mbs=a->mbs,i,j,nz;
20   const PetscInt       *ai=a->i;
21 #if defined(USESHORT)
22   const unsigned short *ib=a->jshort;
23   unsigned short       ibt;
24 #else
25   const PetscInt       *ib=a->j;
26   PetscInt             ibt;
27 #endif
28   PetscInt             nonzerorow = 0;
29 
30   PetscFunctionBegin;
31   ierr = VecSet(zz,0.0);CHKERRQ(ierr);
32   ierr = VecGetArray(xx,(PetscScalar**)&x);CHKERRQ(ierr);
33   ierr = VecGetArray(zz,&z);CHKERRQ(ierr);
34 
35   v  = a->a;
36   for (i=0; i<mbs; i++) {
37     nz   = ai[i+1] - ai[i];  /* length of i_th row of A */
38     if (!nz) continue; /* Move to the next row if the current row is empty */
39     nonzerorow++;
40     x1   = x[i];
41     sum  = v[0]*x1;          /* diagonal term */
42     for (j=1; j<nz; j++) {
43       ibt  = ib[j];
44       vj   = v[j];
45       sum += vj * x[ibt];   /* (strict upper triangular part of A)*x  */
46       z[ibt] += PetscConj(v[j]) * x1;    /* (strict lower triangular part of A)*x  */
47     }
48     z[i] += sum;
49     v    += nz;
50     ib   += nz;
51   }
52 
53   ierr = VecRestoreArray(xx,(PetscScalar**)&x);CHKERRQ(ierr);
54   ierr = VecRestoreArray(zz,&z);CHKERRQ(ierr);
55   ierr = PetscLogFlops(2.0*(2.0*a->nz - nonzerorow) - nonzerorow);CHKERRQ(ierr);
56   PetscFunctionReturn(0);
57 }
58 
59 #undef __FUNCT__
60 #define __FUNCT__ "MatMult_SeqSBAIJ_1"
61 #if defined(USESHORT)
62 PetscErrorCode MatMult_SeqSBAIJ_1_ushort(Mat A,Vec xx,Vec zz)
63 #else
64 PetscErrorCode MatMult_SeqSBAIJ_1(Mat A,Vec xx,Vec zz)
65 #endif
66 {
67   Mat_SeqSBAIJ         *a = (Mat_SeqSBAIJ*)A->data;
68   const PetscScalar    *x;
69   PetscScalar          *z,x1,sum;
70   const MatScalar      *v;
71   MatScalar            vj;
72   PetscErrorCode       ierr;
73   PetscInt             mbs=a->mbs,i,j,nz;
74   const PetscInt       *ai=a->i;
75 #if defined(USESHORT)
76   const unsigned short *ib=a->jshort;
77   unsigned short       ibt;
78 #else
79   const PetscInt       *ib=a->j;
80   PetscInt             ibt;
81 #endif
82   PetscInt             nonzerorow=0;
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     if (!nz) continue; /* Move to the next row if the current row is empty */
93     nonzerorow++;
94     x1   = x[i];
95     sum  = v[0]*x1;                /* diagonal term */
96     for (j=1; j<nz; j++) {
97       ibt = ib[j];
98       vj  = v[j];
99       z[ibt] += vj * x1;       /* (strict lower triangular part of A)*x  */
100       sum    += vj * x[ibt]; /* (strict upper triangular part of A)*x  */
101     }
102     z[i] += sum;
103     v    += nz;
104     ib   += nz;
105   }
106 
107   ierr = VecRestoreArray(xx,(PetscScalar**)&x);CHKERRQ(ierr);
108   ierr = VecRestoreArray(zz,&z);CHKERRQ(ierr);
109   ierr = PetscLogFlops(2.0*(2.0*a->nz - nonzerorow) - nonzerorow);CHKERRQ(ierr);
110   PetscFunctionReturn(0);
111 }
112 
113 #undef __FUNCT__
114 #define __FUNCT__ "MatSOR_SeqSBAIJ"
115 #if defined(USESHORT)
116 PetscErrorCode MatSOR_SeqSBAIJ_ushort(Mat A,Vec bb,PetscReal omega,MatSORType flag,PetscReal fshift,PetscInt its,PetscInt lits,Vec xx)
117 #else
118 PetscErrorCode MatSOR_SeqSBAIJ(Mat A,Vec bb,PetscReal omega,MatSORType flag,PetscReal fshift,PetscInt its,PetscInt lits,Vec xx)
119 #endif
120 {
121   Mat_SeqSBAIJ         *a = (Mat_SeqSBAIJ*)A->data;
122   const MatScalar      *aa=a->a,*v,*v1,*aidiag;
123   PetscScalar          *x,*t,sum;
124   const PetscScalar    *b;
125   MatScalar            tmp;
126   PetscErrorCode       ierr;
127   PetscInt             m=a->mbs,bs=A->rmap->bs,j;
128   const PetscInt       *ai=a->i;
129 #if defined(USESHORT)
130   const unsigned short *aj=a->jshort,*vj,*vj1;
131 #else
132   const PetscInt       *aj=a->j,*vj,*vj1;
133 #endif
134   PetscInt             nz,nz1,i;
135 
136   PetscFunctionBegin;
137   if (flag & SOR_EISENSTAT) SETERRQ(PETSC_ERR_SUP,"No support yet for Eisenstat");
138 
139   its = its*lits;
140   if (its <= 0) SETERRQ2(PETSC_ERR_ARG_WRONG,"Relaxation requires global its %D and local its %D both positive",its,lits);
141 
142   if (bs > 1) SETERRQ(PETSC_ERR_SUP,"SSOR for block size > 1 is not yet implemented");
143 
144   ierr = VecGetArray(xx,&x);CHKERRQ(ierr);
145   if (xx != bb) {
146     ierr = VecGetArray(bb,(PetscScalar**)&b);CHKERRQ(ierr);
147   } else {
148     b = x;
149   }
150 
151   if (!a->idiagvalid) {
152     if (!a->idiag) {
153       ierr = PetscMalloc(m*sizeof(PetscScalar),&a->idiag);CHKERRQ(ierr);
154     }
155     for (i=0; i<a->mbs; i++) a->idiag[i] = 1.0/a->a[a->i[i]];
156     a->idiagvalid = PETSC_TRUE;
157   }
158 
159   if (!a->sor_work) {
160     ierr = PetscMalloc(m*sizeof(PetscScalar),&a->sor_work);CHKERRQ(ierr);
161   }
162   t = a->sor_work;
163 
164   aidiag = a->idiag;
165 
166   if (flag == SOR_APPLY_UPPER) {
167     /* apply (U + D/omega) to the vector */
168     PetscScalar d;
169     for (i=0; i<m; i++) {
170       d    = fshift + aa[ai[i]];
171       nz   = ai[i+1] - ai[i] - 1;
172       vj   = aj + ai[i] + 1;
173       v    = aa + ai[i] + 1;
174       sum  = b[i]*d/omega;
175       PetscSparseDensePlusDot(sum,b,v,vj,nz);
176       x[i] = sum;
177     }
178     ierr = PetscLogFlops(a->nz);CHKERRQ(ierr);
179   }
180 
181   if (flag & SOR_ZERO_INITIAL_GUESS) {
182     if (flag & SOR_FORWARD_SWEEP || flag & SOR_LOCAL_FORWARD_SWEEP){
183       ierr = PetscMemcpy(t,b,m*sizeof(PetscScalar));CHKERRQ(ierr);
184 
185       v  = aa + 1;
186       vj = aj + 1;
187       for (i=0; i<m; i++){
188         nz = ai[i+1] - ai[i] - 1;
189         tmp = - (x[i] = omega*t[i]*aidiag[i]);
190         for (j=0; j<nz; j++) {
191           t[vj[j]] += tmp*v[j];
192         }
193         v  += nz + 1;
194         vj += nz + 1;
195       }
196       ierr = PetscLogFlops(2*a->nz);CHKERRQ(ierr);
197     }
198 
199     if (flag & SOR_BACKWARD_SWEEP || flag & SOR_LOCAL_BACKWARD_SWEEP){
200       int nz2;
201       if (!(flag & SOR_FORWARD_SWEEP || flag & SOR_LOCAL_FORWARD_SWEEP)){
202 #if defined(PETSC_USE_BACKWARD_LOOP)
203 	v  = aa + ai[m] - 1;
204 	vj = aj + ai[m] - 1;
205 	for (i=m-1; i>=0; i--){
206           sum = b[i];
207 	  nz  = ai[i+1] - ai[i] - 1;
208           {PetscInt __i;for(__i=0;__i<nz;__i++) sum -= v[-__i] * x[vj[-__i]];}
209 #else
210 	v  = aa + ai[m-1] + 1;
211 	vj = aj + ai[m-1] + 1;
212 	nz = 0;
213 	for (i=m-1; i>=0; i--){
214           sum = b[i];
215 	  nz2 = ai[i] - ai[i-1] - 1;
216 	  PETSC_Prefetch(v-nz2-1,0,1);
217 	  PETSC_Prefetch(vj-nz2-1,0,1);
218 	  PetscSparseDenseMinusDot(sum,x,v,vj,nz);
219           nz   = nz2;
220 #endif
221           x[i] = omega*sum*aidiag[i];
222 	  v  -= nz + 1;
223 	  vj -= nz + 1;
224 	}
225 	ierr = PetscLogFlops(2*a->nz);CHKERRQ(ierr);
226       } else {
227         v  = aa + ai[m-1] + 1;
228 	vj = aj + ai[m-1] + 1;
229 	nz = 0;
230 	for (i=m-1; i>=0; i--){
231           sum = t[i];
232 	  nz2 = ai[i] - ai[i-1] - 1;
233 	  PETSC_Prefetch(v-nz2-1,0,1);
234 	  PETSC_Prefetch(vj-nz2-1,0,1);
235 	  PetscSparseDenseMinusDot(sum,x,v,vj,nz);
236           x[i] = (1-omega)*x[i] + omega*sum*aidiag[i];
237 	  nz  = nz2;
238 	  v  -= nz + 1;
239 	  vj -= nz + 1;
240 	}
241 	ierr = PetscLogFlops(2*a->nz);CHKERRQ(ierr);
242       }
243     }
244     its--;
245   }
246 
247   while (its--) {
248     /*
249        forward sweep:
250        for i=0,...,m-1:
251          sum[i] = (b[i] - U(i,:)x )/d[i];
252          x[i]   = (1-omega)x[i] + omega*sum[i];
253          b      = b - x[i]*U^T(i,:);
254 
255     */
256     if (flag & SOR_FORWARD_SWEEP || flag & SOR_LOCAL_FORWARD_SWEEP){
257       ierr = PetscMemcpy(t,b,m*sizeof(PetscScalar));CHKERRQ(ierr);
258 
259       for (i=0; i<m; i++){
260         v  = aa + ai[i] + 1; v1=v;
261         vj = aj + ai[i] + 1; vj1=vj;
262         nz = ai[i+1] - ai[i] - 1; nz1=nz;
263         sum = t[i];
264         ierr = PetscLogFlops(4.0*nz-2);CHKERRQ(ierr);
265         while (nz1--) sum -= (*v1++)*x[*vj1++];
266         x[i] = (1-omega)*x[i] + omega*sum*aidiag[i];
267         while (nz--) t[*vj++] -= x[i]*(*v++);
268       }
269     }
270 
271     if (flag & SOR_BACKWARD_SWEEP || flag & SOR_LOCAL_BACKWARD_SWEEP){
272       /*
273        backward sweep:
274        b = b - x[i]*U^T(i,:), i=0,...,n-2
275        for i=m-1,...,0:
276          sum[i] = (b[i] - U(i,:)x )/d[i];
277          x[i]   = (1-omega)x[i] + omega*sum[i];
278       */
279       /* if there was a forward sweep done above then I thing the next two for loops are not needed */
280       ierr = PetscMemcpy(t,b,m*sizeof(PetscScalar));CHKERRQ(ierr);
281 
282       for (i=0; i<m-1; i++){  /* update rhs */
283         v  = aa + ai[i] + 1;
284         vj = aj + ai[i] + 1;
285         nz = ai[i+1] - ai[i] - 1;
286         ierr = PetscLogFlops(2.0*nz-1);CHKERRQ(ierr);
287         while (nz--) t[*vj++] -= x[i]*(*v++);
288       }
289       for (i=m-1; i>=0; i--){
290         v  = aa + ai[i] + 1;
291         vj = aj + ai[i] + 1;
292         nz = ai[i+1] - ai[i] - 1;
293         ierr = PetscLogFlops(2.0*nz-1);CHKERRQ(ierr);
294         sum = t[i];
295         while (nz--) sum -= x[*vj++]*(*v++);
296         x[i] =   (1-omega)*x[i] + omega*sum*aidiag[i];
297       }
298     }
299   }
300 
301   ierr = VecRestoreArray(xx,&x);CHKERRQ(ierr);
302   if (bb != xx) {
303     ierr = VecRestoreArray(bb,(PetscScalar**)&b);CHKERRQ(ierr);
304   }
305   PetscFunctionReturn(0);
306 }
307