xref: /petsc/src/mat/impls/sbaij/seq/relax.h (revision 84df9cb40eca90ea9b18a456fab7a4ecc7f6c1a4)
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   PetscInt             nonzerorow = 0;
30 
31   PetscFunctionBegin;
32   ierr = VecSet(zz,0.0);CHKERRQ(ierr);
33   ierr = VecGetArrayRead(xx,&x);CHKERRQ(ierr);
34   ierr = VecGetArray(zz,&z);CHKERRQ(ierr);
35 
36   v  = a->a;
37   for (i=0; i<mbs; i++) {
38     nz   = ai[i+1] - ai[i];  /* length of i_th row of A */
39     if (!nz) continue; /* Move to the next row if the current row is empty */
40     nonzerorow++;
41     x1   = x[i];
42     sum  = v[0]*x1;          /* diagonal term */
43     for (j=1; j<nz; j++) {
44       ibt  = ib[j];
45       vj   = v[j];
46       sum += vj * x[ibt];   /* (strict upper triangular part of A)*x  */
47       z[ibt] += PetscConj(v[j]) * x1;    /* (strict lower triangular part of A)*x  */
48     }
49     z[i] += sum;
50     v    += nz;
51     ib   += nz;
52   }
53 
54   ierr = VecRestoreArrayRead(xx,&x);CHKERRQ(ierr);
55   ierr = VecRestoreArray(zz,&z);CHKERRQ(ierr);
56   ierr = PetscLogFlops(2.0*(2.0*a->nz - nonzerorow) - nonzerorow);CHKERRQ(ierr);
57   PetscFunctionReturn(0);
58 }
59 
60 #undef __FUNCT__
61 #if defined(USESHORT)
62 #define __FUNCT__ "MatMult_SeqSBAIJ_1_ushort"
63 PetscErrorCode MatMult_SeqSBAIJ_1_ushort(Mat A,Vec xx,Vec zz)
64 #else
65 #define __FUNCT__ "MatMult_SeqSBAIJ_1"
66 PetscErrorCode MatMult_SeqSBAIJ_1(Mat A,Vec xx,Vec zz)
67 #endif
68 {
69   Mat_SeqSBAIJ         *a = (Mat_SeqSBAIJ*)A->data;
70   const PetscScalar    *x;
71   PetscScalar          *z,x1,sum;
72   const MatScalar      *v;
73   MatScalar            vj;
74   PetscErrorCode       ierr;
75   PetscInt             mbs=a->mbs,i,j,nz;
76   const PetscInt       *ai=a->i;
77 #if defined(USESHORT)
78   const unsigned short *ib=a->jshort;
79   unsigned short       ibt;
80 #else
81   const PetscInt       *ib=a->j;
82   PetscInt             ibt;
83 #endif
84   PetscInt             nonzerorow=0;
85 
86   PetscFunctionBegin;
87   ierr = VecSet(zz,0.0);CHKERRQ(ierr);
88   ierr = VecGetArrayRead(xx,&x);CHKERRQ(ierr);
89   ierr = VecGetArray(zz,&z);CHKERRQ(ierr);
90 
91   v  = a->a;
92   for (i=0; i<mbs; i++) {
93     nz   = ai[i+1] - ai[i];        /* length of i_th row of A */
94     if (!nz) continue; /* Move to the next row if the current row is empty */
95     nonzerorow++;
96     x1   = x[i];
97     sum  = v[0]*x1;                /* diagonal term */
98     PetscPrefetchBlock(ib+nz,nz,0,PETSC_PREFETCH_HINT_NTA); /* Indices for the next row (assumes same size as this one) */
99     PetscPrefetchBlock(v+nz,nz,0,PETSC_PREFETCH_HINT_NTA);  /* Entries for the next row */
100     for (j=1; j<nz; j++) {
101       ibt = ib[j];
102       vj  = v[j];
103       z[ibt] += vj * x1;       /* (strict lower triangular part of A)*x  */
104       sum    += vj * x[ibt]; /* (strict upper triangular part of A)*x  */
105     }
106     z[i] += sum;
107     v    += nz;
108     ib   += nz;
109   }
110 
111   ierr = VecRestoreArrayRead(xx,&x);CHKERRQ(ierr);
112   ierr = VecRestoreArray(zz,&z);CHKERRQ(ierr);
113   ierr = PetscLogFlops(2.0*(2.0*a->nz - nonzerorow) - nonzerorow);CHKERRQ(ierr);
114   PetscFunctionReturn(0);
115 }
116 
117 #undef __FUNCT__
118 #if defined(USESHORT)
119 #define __FUNCT__ "MatSOR_SeqSBAIJ_ushort"
120 PetscErrorCode MatSOR_SeqSBAIJ_ushort(Mat A,Vec bb,PetscReal omega,MatSORType flag,PetscReal fshift,PetscInt its,PetscInt lits,Vec xx)
121 #else
122 #define __FUNCT__ "MatSOR_SeqSBAIJ"
123 PetscErrorCode MatSOR_SeqSBAIJ(Mat A,Vec bb,PetscReal omega,MatSORType flag,PetscReal fshift,PetscInt its,PetscInt lits,Vec xx)
124 #endif
125 {
126   Mat_SeqSBAIJ         *a = (Mat_SeqSBAIJ*)A->data;
127   const MatScalar      *aa=a->a,*v,*v1,*aidiag;
128   PetscScalar          *x,*t,sum;
129   const PetscScalar    *b;
130   MatScalar            tmp;
131   PetscErrorCode       ierr;
132   PetscInt             m=a->mbs,bs=A->rmap->bs,j;
133   const PetscInt       *ai=a->i;
134 #if defined(USESHORT)
135   const unsigned short *aj=a->jshort,*vj,*vj1;
136 #else
137   const PetscInt       *aj=a->j,*vj,*vj1;
138 #endif
139   PetscInt             nz,nz1,i;
140 
141   PetscFunctionBegin;
142   if (flag & SOR_EISENSTAT) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_SUP,"No support yet for Eisenstat");
143 
144   its = its*lits;
145   if (its <= 0) SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONG,"Relaxation requires global its %D and local its %D both positive",its,lits);
146 
147   if (bs > 1) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_SUP,"SSOR for block size > 1 is not yet implemented");
148 
149   ierr = VecGetArray(xx,&x);CHKERRQ(ierr);
150   ierr = VecGetArrayRead(bb,&b);CHKERRQ(ierr);
151 
152   if (!a->idiagvalid) {
153     if (!a->idiag) {
154       ierr = PetscMalloc(m*sizeof(PetscScalar),&a->idiag);CHKERRQ(ierr);
155     }
156     for (i=0; i<a->mbs; i++) a->idiag[i] = 1.0/a->a[a->i[i]];
157     a->idiagvalid = PETSC_TRUE;
158   }
159 
160   if (!a->sor_work) {
161     ierr = PetscMalloc(m*sizeof(PetscScalar),&a->sor_work);CHKERRQ(ierr);
162   }
163   t = a->sor_work;
164 
165   aidiag = a->idiag;
166 
167   if (flag == SOR_APPLY_UPPER) {
168     /* apply (U + D/omega) to the vector */
169     PetscScalar d;
170     for (i=0; i<m; i++) {
171       d    = fshift + aa[ai[i]];
172       nz   = ai[i+1] - ai[i] - 1;
173       vj   = aj + ai[i] + 1;
174       v    = aa + ai[i] + 1;
175       sum  = b[i]*d/omega;
176       PetscSparseDensePlusDot(sum,b,v,vj,nz);
177       x[i] = sum;
178     }
179     ierr = PetscLogFlops(a->nz);CHKERRQ(ierr);
180   }
181 
182   if (flag & SOR_ZERO_INITIAL_GUESS) {
183     if (flag & SOR_FORWARD_SWEEP || flag & SOR_LOCAL_FORWARD_SWEEP){
184       ierr = PetscMemcpy(t,b,m*sizeof(PetscScalar));CHKERRQ(ierr);
185 
186       v  = aa + 1;
187       vj = aj + 1;
188       for (i=0; i<m; i++){
189         nz = ai[i+1] - ai[i] - 1;
190         tmp = - (x[i] = omega*t[i]*aidiag[i]);
191         for (j=0; j<nz; j++) {
192           t[vj[j]] += tmp*v[j];
193         }
194         v  += nz + 1;
195         vj += nz + 1;
196       }
197       ierr = PetscLogFlops(2*a->nz);CHKERRQ(ierr);
198     }
199 
200     if (flag & SOR_BACKWARD_SWEEP || flag & SOR_LOCAL_BACKWARD_SWEEP){
201       int nz2;
202       if (!(flag & SOR_FORWARD_SWEEP || flag & SOR_LOCAL_FORWARD_SWEEP)){
203 #if defined(PETSC_USE_BACKWARD_LOOP)
204 	v  = aa + ai[m] - 1;
205 	vj = aj + ai[m] - 1;
206 	for (i=m-1; i>=0; i--){
207           sum = b[i];
208 	  nz  = ai[i+1] - ai[i] - 1;
209           {PetscInt __i;for(__i=0;__i<nz;__i++) sum -= v[-__i] * x[vj[-__i]];}
210 #else
211 	v  = aa + ai[m-1] + 1;
212 	vj = aj + ai[m-1] + 1;
213 	nz = 0;
214 	for (i=m-1; i>=0; i--){
215           sum = b[i];
216           nz2 = ai[i] - ai[i-1] - 1;
217           PETSC_Prefetch(v-nz2-1,0,PETSC_PREFETCH_HINT_NTA);
218           PETSC_Prefetch(vj-nz2-1,0,PETSC_PREFETCH_HINT_NTA);
219           PetscSparseDenseMinusDot(sum,x,v,vj,nz);
220           nz   = nz2;
221 #endif
222           x[i] = omega*sum*aidiag[i];
223 	  v  -= nz + 1;
224 	  vj -= nz + 1;
225 	}
226 	ierr = PetscLogFlops(2*a->nz);CHKERRQ(ierr);
227       } else {
228         v  = aa + ai[m-1] + 1;
229 	vj = aj + ai[m-1] + 1;
230 	nz = 0;
231 	for (i=m-1; i>=0; i--){
232           sum = t[i];
233 	  nz2 = ai[i] - ai[i-1] - 1;
234 	  PETSC_Prefetch(v-nz2-1,0,PETSC_PREFETCH_HINT_NTA);
235 	  PETSC_Prefetch(vj-nz2-1,0,PETSC_PREFETCH_HINT_NTA);
236 	  PetscSparseDenseMinusDot(sum,x,v,vj,nz);
237           x[i] = (1-omega)*x[i] + omega*sum*aidiag[i];
238 	  nz  = nz2;
239 	  v  -= nz + 1;
240 	  vj -= nz + 1;
241 	}
242 	ierr = PetscLogFlops(2*a->nz);CHKERRQ(ierr);
243       }
244     }
245     its--;
246   }
247 
248   while (its--) {
249     /*
250        forward sweep:
251        for i=0,...,m-1:
252          sum[i] = (b[i] - U(i,:)x )/d[i];
253          x[i]   = (1-omega)x[i] + omega*sum[i];
254          b      = b - x[i]*U^T(i,:);
255 
256     */
257     if (flag & SOR_FORWARD_SWEEP || flag & SOR_LOCAL_FORWARD_SWEEP){
258       ierr = PetscMemcpy(t,b,m*sizeof(PetscScalar));CHKERRQ(ierr);
259 
260       for (i=0; i<m; i++){
261         v  = aa + ai[i] + 1; v1=v;
262         vj = aj + ai[i] + 1; vj1=vj;
263         nz = ai[i+1] - ai[i] - 1; nz1=nz;
264         sum = t[i];
265         ierr = PetscLogFlops(4.0*nz-2);CHKERRQ(ierr);
266         while (nz1--) sum -= (*v1++)*x[*vj1++];
267         x[i] = (1-omega)*x[i] + omega*sum*aidiag[i];
268         while (nz--) t[*vj++] -= x[i]*(*v++);
269       }
270     }
271 
272     if (flag & SOR_BACKWARD_SWEEP || flag & SOR_LOCAL_BACKWARD_SWEEP){
273       /*
274        backward sweep:
275        b = b - x[i]*U^T(i,:), i=0,...,n-2
276        for i=m-1,...,0:
277          sum[i] = (b[i] - U(i,:)x )/d[i];
278          x[i]   = (1-omega)x[i] + omega*sum[i];
279       */
280       /* if there was a forward sweep done above then I thing the next two for loops are not needed */
281       ierr = PetscMemcpy(t,b,m*sizeof(PetscScalar));CHKERRQ(ierr);
282 
283       for (i=0; i<m-1; i++){  /* update rhs */
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         while (nz--) t[*vj++] -= x[i]*(*v++);
289       }
290       for (i=m-1; i>=0; i--){
291         v  = aa + ai[i] + 1;
292         vj = aj + ai[i] + 1;
293         nz = ai[i+1] - ai[i] - 1;
294         ierr = PetscLogFlops(2.0*nz-1);CHKERRQ(ierr);
295         sum = t[i];
296         while (nz--) sum -= x[*vj++]*(*v++);
297         x[i] =   (1-omega)*x[i] + omega*sum*aidiag[i];
298       }
299     }
300   }
301 
302   ierr = VecRestoreArray(xx,&x);CHKERRQ(ierr);
303   ierr = VecRestoreArrayRead(bb,&b);CHKERRQ(ierr);
304   PetscFunctionReturn(0);
305 }
306