xref: /petsc/src/mat/impls/sbaij/seq/relax.h (revision f3fe499b4cc4d64bf04aa4f5e4963dcc4eb56541)
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 
29   PetscFunctionBegin;
30   ierr = VecSet(zz,0.0);CHKERRQ(ierr);
31   ierr = VecGetArrayRead(xx,&x);CHKERRQ(ierr);
32   ierr = VecGetArray(zz,&z);CHKERRQ(ierr);
33 
34   v  = a->a;
35   for (i=0; i<mbs; i++) {
36     nz   = ai[i+1] - ai[i];  /* length of i_th row of A */
37     x1   = x[i];
38     sum  = v[0]*x1;          /* diagonal term */
39     for (j=1; j<nz; j++) {
40       ibt  = ib[j];
41       vj   = v[j];
42       sum += vj * x[ibt];   /* (strict upper triangular part of A)*x  */
43       z[ibt] += PetscConj(v[j]) * x1;    /* (strict lower triangular part of A)*x  */
44     }
45     z[i] += sum;
46     v    += nz;
47     ib   += nz;
48   }
49 
50   ierr = VecRestoreArrayRead(xx,&x);CHKERRQ(ierr);
51   ierr = VecRestoreArray(zz,&z);CHKERRQ(ierr);
52   ierr = PetscLogFlops(2.0*(2.0*a->nz - mbs) - mbs);CHKERRQ(ierr);
53   PetscFunctionReturn(0);
54 }
55 
56 #undef __FUNCT__
57 #define __FUNCT__ "MatMult_SeqSBAIJ_1"
58 #if defined(USESHORT)
59 PetscErrorCode MatMult_SeqSBAIJ_1_ushort(Mat A,Vec xx,Vec zz)
60 #else
61 PetscErrorCode MatMult_SeqSBAIJ_1(Mat A,Vec xx,Vec zz)
62 #endif
63 {
64   Mat_SeqSBAIJ         *a = (Mat_SeqSBAIJ*)A->data;
65   const PetscScalar    *x;
66   PetscScalar          *z,x1,sum;
67   const MatScalar      *v;
68   MatScalar            vj;
69   PetscErrorCode       ierr;
70   PetscInt             mbs=a->mbs,i,j,nz;
71   const PetscInt       *ai=a->i;
72 #if defined(USESHORT)
73   const unsigned short *ib=a->jshort;
74   unsigned short       ibt;
75 #else
76   const PetscInt       *ib=a->j;
77   PetscInt             ibt;
78 #endif
79 
80   PetscFunctionBegin;
81   ierr = VecSet(zz,0.0);CHKERRQ(ierr);
82   ierr = VecGetArrayRead(xx,&x);CHKERRQ(ierr);
83   ierr = VecGetArray(zz,&z);CHKERRQ(ierr);
84 
85   v  = a->a;
86   for (i=0; i<mbs; i++) {
87     nz   = ai[i+1] - ai[i];        /* length of i_th row of A */
88     x1   = x[i];
89     sum  = v[0]*x1;                /* diagonal term */
90     for (j=1; j<nz; j++) {
91       ibt = ib[j];
92       vj  = v[j];
93       z[ibt] += vj * x1;       /* (strict lower triangular part of A)*x  */
94       sum    += vj * x[ibt]; /* (strict upper triangular part of A)*x  */
95     }
96     z[i] += sum;
97     v    += nz;
98     ib   += nz;
99   }
100 
101   ierr = VecRestoreArrayRead(xx,&x);CHKERRQ(ierr);
102   ierr = VecRestoreArray(zz,&z);CHKERRQ(ierr);
103   ierr = PetscLogFlops(2.0*(2.0*a->nz - mbs) - mbs);CHKERRQ(ierr);
104   PetscFunctionReturn(0);
105 }
106 
107 #undef __FUNCT__
108 #define __FUNCT__ "MatSOR_SeqSBAIJ"
109 #if defined(USESHORT)
110 PetscErrorCode MatSOR_SeqSBAIJ_ushort(Mat A,Vec bb,PetscReal omega,MatSORType flag,PetscReal fshift,PetscInt its,PetscInt lits,Vec xx)
111 #else
112 PetscErrorCode MatSOR_SeqSBAIJ(Mat A,Vec bb,PetscReal omega,MatSORType flag,PetscReal fshift,PetscInt its,PetscInt lits,Vec xx)
113 #endif
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_COMM_SELF,PETSC_ERR_SUP,"No support yet for Eisenstat");
132 
133   its = its*lits;
134   if (its <= 0) SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONG,"Relaxation requires global its %D and local its %D both positive",its,lits);
135 
136   if (bs > 1) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_SUP,"SSOR for block size > 1 is not yet implemented");
137 
138   ierr = VecGetArray(xx,&x);CHKERRQ(ierr);
139   ierr = VecGetArrayRead(bb,&b);CHKERRQ(ierr);
140 
141   if (!a->idiagvalid) {
142     if (!a->idiag) {
143       ierr = PetscMalloc(m*sizeof(PetscScalar),&a->idiag);CHKERRQ(ierr);
144     }
145     for (i=0; i<a->mbs; i++) a->idiag[i] = 1.0/a->a[a->i[i]];
146     a->idiagvalid = PETSC_TRUE;
147   }
148 
149   if (!a->sor_work) {
150     ierr = PetscMalloc(m*sizeof(PetscScalar),&a->sor_work);CHKERRQ(ierr);
151   }
152   t = a->sor_work;
153 
154   aidiag = a->idiag;
155 
156   if (flag == SOR_APPLY_UPPER) {
157     /* apply (U + D/omega) to the vector */
158     PetscScalar d;
159     for (i=0; i<m; i++) {
160       d    = fshift + aa[ai[i]];
161       nz   = ai[i+1] - ai[i] - 1;
162       vj   = aj + ai[i] + 1;
163       v    = aa + ai[i] + 1;
164       sum  = b[i]*d/omega;
165       PetscSparseDensePlusDot(sum,b,v,vj,nz);
166       x[i] = sum;
167     }
168     ierr = PetscLogFlops(a->nz);CHKERRQ(ierr);
169   }
170 
171   if (flag & SOR_ZERO_INITIAL_GUESS) {
172     if (flag & SOR_FORWARD_SWEEP || flag & SOR_LOCAL_FORWARD_SWEEP){
173       ierr = PetscMemcpy(t,b,m*sizeof(PetscScalar));CHKERRQ(ierr);
174 
175       v  = aa + 1;
176       vj = aj + 1;
177       for (i=0; i<m; i++){
178         nz = ai[i+1] - ai[i] - 1;
179         tmp = - (x[i] = omega*t[i]*aidiag[i]);
180         for (j=0; j<nz; j++) {
181           t[vj[j]] += tmp*v[j];
182         }
183         v  += nz + 1;
184         vj += nz + 1;
185       }
186       ierr = PetscLogFlops(2*a->nz);CHKERRQ(ierr);
187     }
188 
189     if (flag & SOR_BACKWARD_SWEEP || flag & SOR_LOCAL_BACKWARD_SWEEP){
190       int nz2;
191       if (!(flag & SOR_FORWARD_SWEEP || flag & SOR_LOCAL_FORWARD_SWEEP)){
192 #if defined(PETSC_USE_BACKWARD_LOOP)
193 	v  = aa + ai[m] - 1;
194 	vj = aj + ai[m] - 1;
195 	for (i=m-1; i>=0; i--){
196           sum = b[i];
197 	  nz  = ai[i+1] - ai[i] - 1;
198           {PetscInt __i;for(__i=0;__i<nz;__i++) sum -= v[-__i] * x[vj[-__i]];}
199 #else
200 	v  = aa + ai[m-1] + 1;
201 	vj = aj + ai[m-1] + 1;
202 	nz = 0;
203 	for (i=m-1; i>=0; i--){
204           sum = b[i];
205 	  nz2 = ai[i] - ai[i-1] - 1;
206 	  PETSC_Prefetch(v-nz2-1,0,1);
207 	  PETSC_Prefetch(vj-nz2-1,0,1);
208 	  PetscSparseDenseMinusDot(sum,x,v,vj,nz);
209           nz   = nz2;
210 #endif
211           x[i] = omega*sum*aidiag[i];
212 	  v  -= nz + 1;
213 	  vj -= nz + 1;
214 	}
215 	ierr = PetscLogFlops(2*a->nz);CHKERRQ(ierr);
216       } else {
217         v  = aa + ai[m-1] + 1;
218 	vj = aj + ai[m-1] + 1;
219 	nz = 0;
220 	for (i=m-1; i>=0; i--){
221           sum = t[i];
222 	  nz2 = ai[i] - ai[i-1] - 1;
223 	  PETSC_Prefetch(v-nz2-1,0,1);
224 	  PETSC_Prefetch(vj-nz2-1,0,1);
225 	  PetscSparseDenseMinusDot(sum,x,v,vj,nz);
226           x[i] = (1-omega)*x[i] + omega*sum*aidiag[i];
227 	  nz  = nz2;
228 	  v  -= nz + 1;
229 	  vj -= nz + 1;
230 	}
231 	ierr = PetscLogFlops(2*a->nz);CHKERRQ(ierr);
232       }
233     }
234     its--;
235   }
236 
237   while (its--) {
238     /*
239        forward sweep:
240        for i=0,...,m-1:
241          sum[i] = (b[i] - U(i,:)x )/d[i];
242          x[i]   = (1-omega)x[i] + omega*sum[i];
243          b      = b - x[i]*U^T(i,:);
244 
245     */
246     if (flag & SOR_FORWARD_SWEEP || flag & SOR_LOCAL_FORWARD_SWEEP){
247       ierr = PetscMemcpy(t,b,m*sizeof(PetscScalar));CHKERRQ(ierr);
248 
249       for (i=0; i<m; i++){
250         v  = aa + ai[i] + 1; v1=v;
251         vj = aj + ai[i] + 1; vj1=vj;
252         nz = ai[i+1] - ai[i] - 1; nz1=nz;
253         sum = t[i];
254         ierr = PetscLogFlops(4.0*nz-2);CHKERRQ(ierr);
255         while (nz1--) sum -= (*v1++)*x[*vj1++];
256         x[i] = (1-omega)*x[i] + omega*sum*aidiag[i];
257         while (nz--) t[*vj++] -= x[i]*(*v++);
258       }
259     }
260 
261     if (flag & SOR_BACKWARD_SWEEP || flag & SOR_LOCAL_BACKWARD_SWEEP){
262       /*
263        backward sweep:
264        b = b - x[i]*U^T(i,:), i=0,...,n-2
265        for i=m-1,...,0:
266          sum[i] = (b[i] - U(i,:)x )/d[i];
267          x[i]   = (1-omega)x[i] + omega*sum[i];
268       */
269       /* if there was a forward sweep done above then I thing the next two for loops are not needed */
270       ierr = PetscMemcpy(t,b,m*sizeof(PetscScalar));CHKERRQ(ierr);
271 
272       for (i=0; i<m-1; i++){  /* update rhs */
273         v  = aa + ai[i] + 1;
274         vj = aj + ai[i] + 1;
275         nz = ai[i+1] - ai[i] - 1;
276         ierr = PetscLogFlops(2.0*nz-1);CHKERRQ(ierr);
277         while (nz--) t[*vj++] -= x[i]*(*v++);
278       }
279       for (i=m-1; i>=0; i--){
280         v  = aa + ai[i] + 1;
281         vj = aj + ai[i] + 1;
282         nz = ai[i+1] - ai[i] - 1;
283         ierr = PetscLogFlops(2.0*nz-1);CHKERRQ(ierr);
284         sum = t[i];
285         while (nz--) sum -= x[*vj++]*(*v++);
286         x[i] =   (1-omega)*x[i] + omega*sum*aidiag[i];
287       }
288     }
289   }
290 
291   ierr = VecRestoreArray(xx,&x);CHKERRQ(ierr);
292   ierr = VecRestoreArrayRead(bb,&b);CHKERRQ(ierr);
293   PetscFunctionReturn(0);
294 }
295