xref: /petsc/src/mat/impls/sbaij/seq/relax.h (revision 26e7fa26ff6a485bf12e845bcb80b878de68671e)
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 #if defined(USESHORT)
7 #define __FUNCT__ "MatMult_SeqSBAIJ_1_Hermitian_ushort"
8 PetscErrorCode MatMult_SeqSBAIJ_1_Hermitian_ushort(Mat A,Vec xx,Vec zz)
9 #else
10 #define __FUNCT__ "MatMult_SeqSBAIJ_1_Hermitian"
11 PetscErrorCode MatMult_SeqSBAIJ_1_Hermitian(Mat A,Vec xx,Vec zz)
12 #endif
13 {
14   Mat_SeqSBAIJ         *a = (Mat_SeqSBAIJ*)A->data;
15   const PetscScalar    *x;
16   PetscScalar          *z,x1,sum;
17   const MatScalar      *v;
18   MatScalar            vj;
19   PetscErrorCode       ierr;
20   PetscInt             mbs=a->mbs,i,j,nz;
21   const PetscInt       *ai=a->i;
22 #if defined(USESHORT)
23   const unsigned short *ib=a->jshort;
24   unsigned short       ibt;
25 #else
26   const PetscInt       *ib=a->j;
27   PetscInt             ibt;
28 #endif
29 
30   PetscFunctionBegin;
31   ierr = VecSet(zz,0.0);CHKERRQ(ierr);
32   ierr = VecGetArrayRead(xx,&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     x1   = x[i];
39     sum  = v[0]*x1;          /* diagonal term */
40     for (j=1; j<nz; j++) {
41       ibt  = ib[j];
42       vj   = v[j];
43       sum += vj * x[ibt];   /* (strict upper triangular part of A)*x  */
44       z[ibt] += PetscConj(v[j]) * x1;    /* (strict lower triangular part of A)*x  */
45     }
46     z[i] += sum;
47     v    += nz;
48     ib   += nz;
49   }
50 
51   ierr = VecRestoreArrayRead(xx,&x);CHKERRQ(ierr);
52   ierr = VecRestoreArray(zz,&z);CHKERRQ(ierr);
53   ierr = PetscLogFlops(2.0*(2.0*a->nz - mbs) - mbs);CHKERRQ(ierr);
54   PetscFunctionReturn(0);
55 }
56 
57 #undef __FUNCT__
58 #if defined(USESHORT)
59 #define __FUNCT__ "MatMult_SeqSBAIJ_1_ushort"
60 PetscErrorCode MatMult_SeqSBAIJ_1_ushort(Mat A,Vec xx,Vec zz)
61 #else
62 #define __FUNCT__ "MatMult_SeqSBAIJ_1"
63 PetscErrorCode MatMult_SeqSBAIJ_1(Mat A,Vec xx,Vec zz)
64 #endif
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 = VecGetArrayRead(xx,&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 = VecRestoreArrayRead(xx,&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 #if defined(USESHORT)
111 #define __FUNCT__ "MatSOR_SeqSBAIJ_ushort"
112 PetscErrorCode MatSOR_SeqSBAIJ_ushort(Mat A,Vec bb,PetscReal omega,MatSORType flag,PetscReal fshift,PetscInt its,PetscInt lits,Vec xx)
113 #else
114 #define __FUNCT__ "MatSOR_SeqSBAIJ"
115 PetscErrorCode MatSOR_SeqSBAIJ(Mat A,Vec bb,PetscReal omega,MatSORType flag,PetscReal fshift,PetscInt its,PetscInt lits,Vec xx)
116 #endif
117 {
118   Mat_SeqSBAIJ         *a = (Mat_SeqSBAIJ*)A->data;
119   const MatScalar      *aa=a->a,*v,*v1,*aidiag;
120   PetscScalar          *x,*t,sum;
121   const PetscScalar    *b;
122   MatScalar            tmp;
123   PetscErrorCode       ierr;
124   PetscInt             m=a->mbs,bs=A->rmap->bs,j;
125   const PetscInt       *ai=a->i;
126 #if defined(USESHORT)
127   const unsigned short *aj=a->jshort,*vj,*vj1;
128 #else
129   const PetscInt       *aj=a->j,*vj,*vj1;
130 #endif
131   PetscInt             nz,nz1,i;
132 
133   PetscFunctionBegin;
134   if (flag & SOR_EISENSTAT) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_SUP,"No support yet for Eisenstat");
135 
136   its = its*lits;
137   if (its <= 0) SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONG,"Relaxation requires global its %D and local its %D both positive",its,lits);
138 
139   if (bs > 1) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_SUP,"SSOR for block size > 1 is not yet implemented");
140 
141   ierr = VecGetArray(xx,&x);CHKERRQ(ierr);
142   ierr = VecGetArrayRead(bb,&b);CHKERRQ(ierr);
143 
144   if (!a->idiagvalid) {
145     if (!a->idiag) {
146       ierr = PetscMalloc(m*sizeof(PetscScalar),&a->idiag);CHKERRQ(ierr);
147     }
148     for (i=0; i<a->mbs; i++) a->idiag[i] = 1.0/a->a[a->i[i]];
149     a->idiagvalid = PETSC_TRUE;
150   }
151 
152   if (!a->sor_work) {
153     ierr = PetscMalloc(m*sizeof(PetscScalar),&a->sor_work);CHKERRQ(ierr);
154   }
155   t = a->sor_work;
156 
157   aidiag = a->idiag;
158 
159   if (flag == SOR_APPLY_UPPER) {
160     /* apply (U + D/omega) to the vector */
161     PetscScalar d;
162     for (i=0; i<m; i++) {
163       d    = fshift + aa[ai[i]];
164       nz   = ai[i+1] - ai[i] - 1;
165       vj   = aj + ai[i] + 1;
166       v    = aa + ai[i] + 1;
167       sum  = b[i]*d/omega;
168       PetscSparseDensePlusDot(sum,b,v,vj,nz);
169       x[i] = sum;
170     }
171     ierr = PetscLogFlops(a->nz);CHKERRQ(ierr);
172   }
173 
174   if (flag & SOR_ZERO_INITIAL_GUESS) {
175     if (flag & SOR_FORWARD_SWEEP || flag & SOR_LOCAL_FORWARD_SWEEP){
176       ierr = PetscMemcpy(t,b,m*sizeof(PetscScalar));CHKERRQ(ierr);
177 
178       v  = aa + 1;
179       vj = aj + 1;
180       for (i=0; i<m; i++){
181         nz = ai[i+1] - ai[i] - 1;
182         tmp = - (x[i] = omega*t[i]*aidiag[i]);
183         for (j=0; j<nz; j++) {
184           t[vj[j]] += tmp*v[j];
185         }
186         v  += nz + 1;
187         vj += nz + 1;
188       }
189       ierr = PetscLogFlops(2*a->nz);CHKERRQ(ierr);
190     }
191 
192     if (flag & SOR_BACKWARD_SWEEP || flag & SOR_LOCAL_BACKWARD_SWEEP){
193       int nz2;
194       if (!(flag & SOR_FORWARD_SWEEP || flag & SOR_LOCAL_FORWARD_SWEEP)){
195 #if defined(PETSC_USE_BACKWARD_LOOP)
196 	v  = aa + ai[m] - 1;
197 	vj = aj + ai[m] - 1;
198 	for (i=m-1; i>=0; i--){
199           sum = b[i];
200 	  nz  = ai[i+1] - ai[i] - 1;
201           {PetscInt __i;for(__i=0;__i<nz;__i++) sum -= v[-__i] * x[vj[-__i]];}
202 #else
203 	v  = aa + ai[m-1] + 1;
204 	vj = aj + ai[m-1] + 1;
205 	nz = 0;
206 	for (i=m-1; i>=0; i--){
207           sum = b[i];
208           nz2 = ai[i] - ai[i-1] - 1;
209           PETSC_Prefetch(v-nz2-1,0,PETSC_PREFETCH_HINT_NTA);
210           PETSC_Prefetch(vj-nz2-1,0,PETSC_PREFETCH_HINT_NTA);
211           PetscSparseDenseMinusDot(sum,x,v,vj,nz);
212           nz   = nz2;
213 #endif
214           x[i] = omega*sum*aidiag[i];
215 	  v  -= nz + 1;
216 	  vj -= nz + 1;
217 	}
218 	ierr = PetscLogFlops(2*a->nz);CHKERRQ(ierr);
219       } else {
220         v  = aa + ai[m-1] + 1;
221 	vj = aj + ai[m-1] + 1;
222 	nz = 0;
223 	for (i=m-1; i>=0; i--){
224           sum = t[i];
225 	  nz2 = ai[i] - ai[i-1] - 1;
226 	  PETSC_Prefetch(v-nz2-1,0,PETSC_PREFETCH_HINT_NTA);
227 	  PETSC_Prefetch(vj-nz2-1,0,PETSC_PREFETCH_HINT_NTA);
228 	  PetscSparseDenseMinusDot(sum,x,v,vj,nz);
229           x[i] = (1-omega)*x[i] + omega*sum*aidiag[i];
230 	  nz  = nz2;
231 	  v  -= nz + 1;
232 	  vj -= nz + 1;
233 	}
234 	ierr = PetscLogFlops(2*a->nz);CHKERRQ(ierr);
235       }
236     }
237     its--;
238   }
239 
240   while (its--) {
241     /*
242        forward sweep:
243        for i=0,...,m-1:
244          sum[i] = (b[i] - U(i,:)x )/d[i];
245          x[i]   = (1-omega)x[i] + omega*sum[i];
246          b      = b - x[i]*U^T(i,:);
247 
248     */
249     if (flag & SOR_FORWARD_SWEEP || flag & SOR_LOCAL_FORWARD_SWEEP){
250       ierr = PetscMemcpy(t,b,m*sizeof(PetscScalar));CHKERRQ(ierr);
251 
252       for (i=0; i<m; i++){
253         v  = aa + ai[i] + 1; v1=v;
254         vj = aj + ai[i] + 1; vj1=vj;
255         nz = ai[i+1] - ai[i] - 1; nz1=nz;
256         sum = t[i];
257         ierr = PetscLogFlops(4.0*nz-2);CHKERRQ(ierr);
258         while (nz1--) sum -= (*v1++)*x[*vj1++];
259         x[i] = (1-omega)*x[i] + omega*sum*aidiag[i];
260         while (nz--) t[*vj++] -= x[i]*(*v++);
261       }
262     }
263 
264     if (flag & SOR_BACKWARD_SWEEP || flag & SOR_LOCAL_BACKWARD_SWEEP){
265       /*
266        backward sweep:
267        b = b - x[i]*U^T(i,:), i=0,...,n-2
268        for i=m-1,...,0:
269          sum[i] = (b[i] - U(i,:)x )/d[i];
270          x[i]   = (1-omega)x[i] + omega*sum[i];
271       */
272       /* if there was a forward sweep done above then I thing the next two for loops are not needed */
273       ierr = PetscMemcpy(t,b,m*sizeof(PetscScalar));CHKERRQ(ierr);
274 
275       for (i=0; i<m-1; i++){  /* update rhs */
276         v  = aa + ai[i] + 1;
277         vj = aj + ai[i] + 1;
278         nz = ai[i+1] - ai[i] - 1;
279         ierr = PetscLogFlops(2.0*nz-1);CHKERRQ(ierr);
280         while (nz--) t[*vj++] -= x[i]*(*v++);
281       }
282       for (i=m-1; i>=0; i--){
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         sum = t[i];
288         while (nz--) sum -= x[*vj++]*(*v++);
289         x[i] =   (1-omega)*x[i] + omega*sum*aidiag[i];
290       }
291     }
292   }
293 
294   ierr = VecRestoreArray(xx,&x);CHKERRQ(ierr);
295   ierr = VecRestoreArrayRead(bb,&b);CHKERRQ(ierr);
296   PetscFunctionReturn(0);
297 }
298