Actual source code: ex30.c
1: static char help[] = "Tests Sliced operations\n\n";
3: #include petscda.h
7: int main(int argc,char *argv[])
8: {
9: char mat_type[256] = "aij"; /* default matrix type */
11: MPI_Comm comm;
12: PetscMPIInt rank,size;
13: Sliced slice;
14: PetscInt i,bs=1,N=5,n,m,rstart,ghosts[2],*d_nnz,*o_nnz,dfill[4]={1,0,0,1},ofill[4]={1,1,1,1};
15: PetscReal alpha=1,K=1,rho0=1,u0=0,sigma=0.2;
16: PetscTruth useblock=PETSC_TRUE;
17: PetscScalar *xx;
18: Mat A;
19: Vec x,b,lf;
21: PetscInitialize(&argc,&argv,0,help);
22: comm = PETSC_COMM_WORLD;
23: MPI_Comm_size(comm,&size);
24: MPI_Comm_rank(comm,&rank);
26: PetscOptionsBegin(comm,0,"Options for Sliced test",0);
27: {
28: PetscOptionsInt("-n","Global number of nodes","",N,&N,PETSC_NULL);
29: PetscOptionsInt("-bs","Block size (1 or 2)","",bs,&bs,PETSC_NULL);
30: if (bs != 1) {
31: if (bs != 2) SETERRQ(1,"Block size must be 1 or 2");
32: PetscOptionsReal("-alpha","Inverse time step for wave operator","",alpha,&alpha,PETSC_NULL);
33: PetscOptionsReal("-K","Bulk modulus of compressibility","",K,&K,PETSC_NULL);
34: PetscOptionsReal("-rho0","Reference density","",rho0,&rho0,PETSC_NULL);
35: PetscOptionsReal("-u0","Reference velocity","",u0,&u0,PETSC_NULL);
36: PetscOptionsReal("-sigma","Width of Gaussian density perturbation","",sigma,&sigma,PETSC_NULL);
37: PetscOptionsTruth("-block","Use block matrix assembly","",useblock,&useblock,PETSC_NULL);
38: }
39: PetscOptionsString("-sliced_mat_type","Matrix type to use (aij or baij)","",mat_type,mat_type,sizeof mat_type,PETSC_NULL);
40: }
41: PetscOptionsEnd();
43: /* Split ownership, set up periodic grid in 1D */
44: n = PETSC_DECIDE;
45: PetscSplitOwnership(comm,&n,&N);
46: rstart = 0;
47: MPI_Scan(&n,&rstart,1,MPIU_INT,MPI_SUM,comm);
48: rstart -= n;
49: ghosts[0] = (N+rstart-1)%N;
50: ghosts[1] = (rstart+n)%N;
52: SlicedCreate(comm,&slice);
53: SlicedSetGhosts(slice,bs,n,2,ghosts);
54: PetscMalloc2(n,PetscInt,&d_nnz,n,PetscInt,&o_nnz);
55: for (i=0; i<n; i++) {
56: if (size > 1 && (i==0 || i==n-1)) {
57: d_nnz[i] = 2;
58: o_nnz[i] = 1;
59: } else {
60: d_nnz[i] = 3;
61: o_nnz[i] = 0;
62: }
63: }
64: SlicedSetPreallocation(slice,0,d_nnz,0,o_nnz); /* Currently does not copy X_nnz so we can't free them until after SlicedGetMatrix */
66: if (!useblock) {SlicedSetBlockFills(slice,dfill,ofill);} /* Irrelevant for baij formats */
67: SlicedGetMatrix(slice,mat_type,&A);
68: PetscFree2(d_nnz,o_nnz);
69: MatSetOption(A,MAT_NEW_NONZERO_ALLOCATION_ERR,PETSC_TRUE);
71: SlicedCreateGlobalVector(slice,&x);
72: VecDuplicate(x,&b);
74: VecGhostGetLocalForm(x,&lf);
75: VecGetSize(lf,&m);
76: if (m != (n+2)*bs) SETERRQ2(1,"size of local form %D, expected %D",m,(n+2)*bs);
77: VecGetArray(lf,&xx);
78: for (i=0; i<n; i++) {
79: PetscInt row[2],col[9],im,ip;
80: PetscScalar v[12];
81: const PetscReal xref = 2.0*(rstart+i)/N - 1; /* [-1,1] */
82: const PetscReal h = 1.0/N; /* grid spacing */
83: im = (i==0) ? n : i-1;
84: ip = (i==n-1) ? n+1 : i+1;
85: switch (bs) {
86: case 1: /* Laplacian with periodic boundaries */
87: col[0] = im; col[1] = i; col[2] = ip;
88: v[0] = -h; v[1] = 2*h; v[2] = -h;
89: MatSetValuesLocal(A,1,&i,3,col,v,INSERT_VALUES);
90: xx[i] = sin(xref*PETSC_PI);
91: break;
92: case 2: /* Linear acoustic wave operator in variables [rho, u], central differences, periodic, timestep 1/alpha */
93: v[0] = -0.5*u0; v[1] = -0.5*K; v[2] = alpha; v[3] = 0; v[4] = 0.5*u0; v[5] = 0.5*K;
94: v[6] = -0.5/rho0; v[7] = -0.5*u0; v[8] = 0; v[9] = alpha; v[10] = 0.5/rho0; v[11] = 0.5*u0;
95: if (useblock) {
96: row[0] = i; col[0] = im; col[1] = i; col[2] = ip;
97: MatSetValuesBlockedLocal(A,1,row,3,col,v,INSERT_VALUES);
98: } else {
99: row[0] = 2*i; row[1] = 2*i+1;
100: col[0] = 2*im; col[1] = 2*im+1; col[2] = 2*i; col[3] = 2*ip; col[4] = 2*ip+1;
101: v[3] = v[4]; v[4] = v[5]; /* pack values in first row */
102: MatSetValuesLocal(A,1,row,5,col,v,INSERT_VALUES);
103: col[2] = 2*i+1;
104: v[8] = v[9]; v[9] = v[10]; v[10] = v[11]; /* pack values in second row */
105: MatSetValuesLocal(A,1,row+1,5,col,v+6,INSERT_VALUES);
106: }
107: /* Set current state (gaussian density perturbation) */
108: xx[2*i] = 0.2*exp(-PetscSqr(xref)/(2*PetscSqr(sigma)));
109: xx[2*i+1] = 0;
110: break;
111: default: SETERRQ1(1,"not implemented for block size %D",bs);
112: }
113: }
114: VecRestoreArray(lf,&xx);
115: VecGhostRestoreLocalForm(x,&lf);
116: MatAssemblyBegin(A,MAT_FINAL_ASSEMBLY);
117: MatAssemblyEnd(A,MAT_FINAL_ASSEMBLY);
119: MatMult(A,x,b);
120: MatView(A,PETSC_VIEWER_STDOUT_WORLD);
121: VecView(x,PETSC_VIEWER_STDOUT_WORLD);
122: VecView(b,PETSC_VIEWER_STDOUT_WORLD);
124: /* Update the ghosted values, view the result on rank 0. */
125: VecGhostUpdateBegin(b,INSERT_VALUES,SCATTER_FORWARD);
126: VecGhostUpdateEnd(b,INSERT_VALUES,SCATTER_FORWARD);
127: if (!rank) {
128: VecGhostGetLocalForm(b,&lf);
129: PetscViewerASCIIPrintf(PETSC_VIEWER_STDOUT_SELF,"Local form of b on rank 0, last two nodes are ghost nodes\n");
130: VecView(lf,PETSC_VIEWER_STDOUT_SELF);
131: VecGhostRestoreLocalForm(b,&lf);
132: }
134: SlicedDestroy(slice);
135: VecDestroy(x);
136: VecDestroy(b);
137: MatDestroy(A);
138: PetscFinalize();
139: return 0;
140: }