xref: /petsc/src/mat/tests/ex18.c (revision c87ba875e4007ad659b117ea274f03d5f4cd5ea7) !
1 static char help[] = "Tests the use of MatZeroRowsColumns() for parallel matrices.\n\
2 Contributed-by: Stephan Kramer <s.kramer@imperial.ac.uk>\n\n";
3 
4 #include <petscmat.h>
5 
6 int main(int argc,char **args)
7 {
8   Mat            A;
9   Vec            x, rhs, y;
10   PetscInt       i,j,k,b,m = 3,n,nlocal=2,bs=1,Ii,J;
11   PetscInt       *boundary_nodes, nboundary_nodes, *boundary_indices;
12   PetscMPIInt    rank,size;
13   PetscErrorCode ierr;
14   PetscScalar    v,v0,v1,v2,a0=0.1,a,rhsval, *boundary_values,diag = 1.0;
15   PetscReal      norm;
16   char           convname[64];
17   PetscBool      upwind = PETSC_FALSE, nonlocalBC = PETSC_FALSE, zerorhs = PETSC_TRUE, convert = PETSC_FALSE;
18 
19   ierr = PetscInitialize(&argc,&args,(char*)0,help);if (ierr) return ierr;
20   ierr = MPI_Comm_rank(PETSC_COMM_WORLD,&rank);CHKERRQ(ierr);
21   ierr = MPI_Comm_size(PETSC_COMM_WORLD,&size);CHKERRQ(ierr);
22   n = nlocal*size;
23 
24   ierr = PetscOptionsGetInt(NULL,NULL, "-bs", &bs, NULL);CHKERRQ(ierr);
25   ierr = PetscOptionsGetBool(NULL,NULL, "-nonlocal_bc", &nonlocalBC, NULL);CHKERRQ(ierr);
26   ierr = PetscOptionsGetScalar(NULL,NULL, "-diag", &diag, NULL);CHKERRQ(ierr);
27   ierr = PetscOptionsGetString(NULL,NULL,"-convname",convname,sizeof(convname),&convert);CHKERRQ(ierr);
28   ierr = PetscOptionsGetBool(NULL,NULL, "-zerorhs", &zerorhs, NULL);CHKERRQ(ierr);
29 
30   ierr = MatCreate(PETSC_COMM_WORLD,&A);CHKERRQ(ierr);
31   ierr = MatSetSizes(A,PETSC_DECIDE,PETSC_DECIDE,m*n*bs,m*n*bs);CHKERRQ(ierr);
32   ierr = MatSetFromOptions(A);CHKERRQ(ierr);
33   ierr = MatSetUp(A);CHKERRQ(ierr);
34 
35   ierr = VecCreate(PETSC_COMM_WORLD, &rhs);CHKERRQ(ierr);
36   ierr = VecSetSizes(rhs, PETSC_DECIDE, m*n*bs);CHKERRQ(ierr);
37   ierr = VecSetFromOptions(rhs);CHKERRQ(ierr);
38   ierr = VecSetUp(rhs);CHKERRQ(ierr);
39 
40   rhsval = 0.0;
41   for (i=0; i<m; i++) {
42     for (j=nlocal*rank; j<nlocal*(rank+1); j++) {
43       a = a0;
44       for (b=0; b<bs; b++) {
45         /* let's start with a 5-point stencil diffusion term */
46         v = -1.0;  Ii = (j + n*i)*bs + b;
47         if (i>0)   {J = Ii - n*bs; ierr = MatSetValues(A,1,&Ii,1,&J,&v,ADD_VALUES);CHKERRQ(ierr);}
48         if (i<m-1) {J = Ii + n*bs; ierr = MatSetValues(A,1,&Ii,1,&J,&v,ADD_VALUES);CHKERRQ(ierr);}
49         if (j>0)   {J = Ii - 1*bs; ierr = MatSetValues(A,1,&Ii,1,&J,&v,ADD_VALUES);CHKERRQ(ierr);}
50         if (j<n-1) {J = Ii + 1*bs; ierr = MatSetValues(A,1,&Ii,1,&J,&v,ADD_VALUES);CHKERRQ(ierr);}
51         v = 4.0; ierr = MatSetValues(A,1,&Ii,1,&Ii,&v,ADD_VALUES);CHKERRQ(ierr);
52         if (upwind) {
53           /* now add a 2nd order upwind advection term to add a little asymmetry */
54           if (j>2) {
55             J = Ii-2*bs; v2 = 0.5*a; v1 = -2.0*a; v0 = 1.5*a;
56             ierr = MatSetValues(A,1,&Ii,1,&J,&v2,ADD_VALUES);CHKERRQ(ierr);
57           } else {
58             /* fall back to 1st order upwind */
59             v1 = -1.0*a; v0 = 1.0*a;
60           };
61           if (j>1) {J = Ii-1*bs; ierr = MatSetValues(A,1,&Ii,1,&J,&v1,ADD_VALUES);CHKERRQ(ierr);}
62           ierr = MatSetValues(A,1,&Ii,1,&Ii,&v0,ADD_VALUES);CHKERRQ(ierr);
63           a /= 10.; /* use a different velocity for the next component */
64           /* add a coupling to the previous and next components */
65           v = 0.5;
66           if (b>0) {J = Ii - 1; ierr = MatSetValues(A,1,&Ii,1,&J,&v,ADD_VALUES);CHKERRQ(ierr);}
67           if (b<bs-1) {J = Ii + 1; ierr = MatSetValues(A,1,&Ii,1,&J,&v,ADD_VALUES);CHKERRQ(ierr);}
68         }
69         /* make up some rhs */
70         ierr = VecSetValue(rhs, Ii, rhsval, INSERT_VALUES);CHKERRQ(ierr);
71         rhsval += 1.0;
72       }
73     }
74   }
75   ierr = MatAssemblyBegin(A,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
76   ierr = MatAssemblyEnd(A,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
77 
78   if (convert) { /* Test different Mat implementations */
79     Mat B;
80 
81     ierr = MatConvert(A,convname,MAT_INITIAL_MATRIX,&B);CHKERRQ(ierr);
82     ierr = MatDestroy(&A);CHKERRQ(ierr);
83     A    = B;
84   }
85 
86   ierr = VecAssemblyBegin(rhs);CHKERRQ(ierr);
87   ierr = VecAssemblyEnd(rhs);CHKERRQ(ierr);
88   /* set rhs to zero to simplify */
89   if (zerorhs) {
90     ierr = VecZeroEntries(rhs);CHKERRQ(ierr);
91   }
92 
93   if (nonlocalBC) {
94     /*version where boundary conditions are set by processes that don't necessarily own the nodes */
95     if (!rank) {
96       nboundary_nodes = size>m ? nlocal : m-size+nlocal;
97       ierr = PetscMalloc1(nboundary_nodes,&boundary_nodes);CHKERRQ(ierr);
98       k = 0;
99       for (i=size; i<m; i++,k++) {boundary_nodes[k] = n*i;};
100     } else if (rank < m) {
101       nboundary_nodes = nlocal+1;
102       ierr = PetscMalloc1(nboundary_nodes,&boundary_nodes);CHKERRQ(ierr);
103       boundary_nodes[0] = rank*n;
104       k = 1;
105     } else {
106       nboundary_nodes = nlocal;
107       ierr = PetscMalloc1(nboundary_nodes,&boundary_nodes);CHKERRQ(ierr);
108       k = 0;
109     }
110     for (j=nlocal*rank; j<nlocal*(rank+1); j++,k++) {boundary_nodes[k] = j;};
111   } else {
112     /*version where boundary conditions are set by the node owners only */
113     ierr = PetscMalloc1(m*n,&boundary_nodes);CHKERRQ(ierr);
114     k=0;
115     for (j=0; j<n; j++) {
116       Ii = j;
117       if (Ii>=rank*m*nlocal && Ii<(rank+1)*m*nlocal) boundary_nodes[k++] = Ii;
118     }
119     for (i=1; i<m; i++) {
120       Ii = n*i;
121       if (Ii>=rank*m*nlocal && Ii<(rank+1)*m*nlocal) boundary_nodes[k++] = Ii;
122     }
123     nboundary_nodes = k;
124   }
125 
126   ierr = VecDuplicate(rhs, &x);CHKERRQ(ierr);
127   ierr = VecZeroEntries(x);CHKERRQ(ierr);
128   ierr = PetscMalloc2(nboundary_nodes*bs,&boundary_indices,nboundary_nodes*bs,&boundary_values);CHKERRQ(ierr);
129   for (k=0; k<nboundary_nodes; k++) {
130     Ii = boundary_nodes[k]*bs;
131     v = 1.0*boundary_nodes[k];
132     for (b=0; b<bs; b++, Ii++) {
133       boundary_indices[k*bs+b] = Ii;
134       boundary_values[k*bs+b] = v;
135       ierr = PetscSynchronizedPrintf(PETSC_COMM_WORLD, "%d %D %f\n", rank, Ii, (double)PetscRealPart(v));CHKERRQ(ierr);
136       v += 0.1;
137     }
138   }
139   ierr = PetscSynchronizedFlush(PETSC_COMM_WORLD, NULL);CHKERRQ(ierr);
140   ierr = VecSetValues(x, nboundary_nodes*bs, boundary_indices, boundary_values, INSERT_VALUES);CHKERRQ(ierr);
141   ierr = VecAssemblyBegin(x);CHKERRQ(ierr);
142   ierr = VecAssemblyEnd(x);CHKERRQ(ierr);
143 
144   /* We can check the rhs returned by MatZeroColumns by computing y=rhs-A*x  and overwriting the boundary entries with boundary values */
145   ierr = VecDuplicate(x, &y);CHKERRQ(ierr);
146   ierr = MatMult(A, x, y);CHKERRQ(ierr);
147   ierr = VecAYPX(y, -1.0, rhs);CHKERRQ(ierr);
148   for (k=0; k<nboundary_nodes*bs; k++) boundary_values[k] *= diag;
149   ierr = VecSetValues(y, nboundary_nodes*bs, boundary_indices, boundary_values, INSERT_VALUES);CHKERRQ(ierr);
150   ierr = VecAssemblyBegin(y);CHKERRQ(ierr);
151   ierr = VecAssemblyEnd(y);CHKERRQ(ierr);
152 
153   ierr = PetscPrintf(PETSC_COMM_WORLD, "*** Matrix A and vector x:\n");CHKERRQ(ierr);
154   ierr = MatView(A, PETSC_VIEWER_STDOUT_WORLD);CHKERRQ(ierr);
155   ierr = VecView(x,PETSC_VIEWER_STDOUT_WORLD);CHKERRQ(ierr);
156 
157   ierr = MatZeroRowsColumns(A, nboundary_nodes*bs, boundary_indices, diag, x, rhs);CHKERRQ(ierr);
158   ierr = PetscPrintf(PETSC_COMM_WORLD, "*** Vector rhs returned by MatZeroRowsColumns\n");CHKERRQ(ierr);
159   ierr = VecView(rhs,PETSC_VIEWER_STDOUT_WORLD);CHKERRQ(ierr);
160   ierr = VecAXPY(y, -1.0, rhs);CHKERRQ(ierr);
161   ierr = VecNorm(y, NORM_INFINITY, &norm);CHKERRQ(ierr);
162   if (norm > 1.0e-10) {
163     ierr = PetscPrintf(PETSC_COMM_WORLD, "*** Difference between rhs and y, inf-norm: %f\n", (double)norm);CHKERRQ(ierr);
164     ierr = VecView(y,PETSC_VIEWER_STDOUT_WORLD);CHKERRQ(ierr);
165     SETERRQ(PETSC_COMM_WORLD, PETSC_ERR_PLIB, "Bug in MatZeroRowsColumns");
166   }
167 
168   ierr = PetscFree(boundary_nodes);CHKERRQ(ierr);
169   ierr = PetscFree2(boundary_indices,boundary_values);CHKERRQ(ierr);
170   ierr = VecDestroy(&x);CHKERRQ(ierr);
171   ierr = VecDestroy(&y);CHKERRQ(ierr);
172   ierr = VecDestroy(&rhs);CHKERRQ(ierr);
173   ierr = MatDestroy(&A);CHKERRQ(ierr);
174 
175   ierr = PetscFinalize();
176   return ierr;
177 }
178 
179 
180 /*TEST
181 
182    test:
183       suffix: 0
184 
185    test:
186       suffix: 1
187       nsize: 2
188 
189    test:
190       suffix: 10
191       nsize: 2
192       args: -bs 2 -nonlocal_bc
193 
194    test:
195       suffix: 11
196       nsize: 7
197       args: -bs 2 -nonlocal_bc
198 
199    test:
200       suffix: 12
201       args: -bs 2 -nonlocal_bc -mat_type baij
202 
203    test:
204       suffix: 13
205       nsize: 2
206       args: -bs 2 -nonlocal_bc -mat_type baij
207 
208    test:
209       suffix: 14
210       nsize: 7
211       args: -bs 2 -nonlocal_bc -mat_type baij
212 
213    test:
214       suffix: 2
215       nsize: 7
216 
217    test:
218       suffix: 3
219       args: -mat_type baij
220 
221    test:
222       suffix: 4
223       nsize: 2
224       args: -mat_type baij
225 
226    test:
227       suffix: 5
228       nsize: 7
229       args: -mat_type baij
230 
231    test:
232       suffix: 6
233       args: -bs 2 -mat_type baij
234 
235    test:
236       suffix: 7
237       nsize: 2
238       args: -bs 2 -mat_type baij
239 
240    test:
241       suffix: 8
242       nsize: 7
243       args: -bs 2 -mat_type baij
244 
245    test:
246       suffix: 9
247       args: -bs 2 -nonlocal_bc
248 
249    test:
250       suffix: 15
251       args: -bs 2 -nonlocal_bc -convname shell
252 
253    test:
254       suffix: 16
255       nsize: 2
256       args: -bs 2 -nonlocal_bc -convname shell
257 
258    test:
259       suffix: 17
260       args: -bs 2 -nonlocal_bc -convname dense
261 
262    testset:
263       suffix: full
264       nsize: {{1 3}separate output}
265       args: -diag {{0.12 -0.13}separate output} -convname {{aij shell baij}separate output} -zerorhs 0
266 TEST*/
267