1c4762a1bSJed Brown 2c4762a1bSJed Brown /* 3c4762a1bSJed Brown Simple example to show how PETSc programs can be run from MATLAB. 4c4762a1bSJed Brown See ex12.m. 5c4762a1bSJed Brown */ 6c4762a1bSJed Brown 7c4762a1bSJed Brown static char help[] = "Solves the one dimensional heat equation.\n\n"; 8c4762a1bSJed Brown 9c4762a1bSJed Brown #include <petscdm.h> 10c4762a1bSJed Brown #include <petscdmda.h> 11c4762a1bSJed Brown 12c4762a1bSJed Brown int main(int argc,char **argv) 13c4762a1bSJed Brown { 14c4762a1bSJed Brown PetscMPIInt rank,size; 15c4762a1bSJed Brown PetscInt M = 14,time_steps = 20,w=1,s=1,localsize,j,i,mybase,myend,globalsize; 16c4762a1bSJed Brown DM da; 17c4762a1bSJed Brown Vec global,local; 18c4762a1bSJed Brown PetscScalar *globalptr,*localptr; 19c4762a1bSJed Brown PetscReal h,k; 20c4762a1bSJed Brown 21*9566063dSJacob Faibussowitsch PetscCall(PetscInitialize(&argc,&argv,(char*)0,help)); 22*9566063dSJacob Faibussowitsch PetscCall(PetscOptionsGetInt(NULL,NULL,"-M",&M,NULL)); 23*9566063dSJacob Faibussowitsch PetscCall(PetscOptionsGetInt(NULL,NULL,"-time",&time_steps,NULL)); 24c4762a1bSJed Brown 25c4762a1bSJed Brown /* Set up the array */ 26*9566063dSJacob Faibussowitsch PetscCall(DMDACreate1d(PETSC_COMM_WORLD,DM_BOUNDARY_NONE,M,w,s,NULL,&da)); 27*9566063dSJacob Faibussowitsch PetscCall(DMSetFromOptions(da)); 28*9566063dSJacob Faibussowitsch PetscCall(DMSetUp(da)); 29*9566063dSJacob Faibussowitsch PetscCall(DMCreateGlobalVector(da,&global)); 30*9566063dSJacob Faibussowitsch PetscCallMPI(MPI_Comm_rank(PETSC_COMM_WORLD,&rank)); 31*9566063dSJacob Faibussowitsch PetscCallMPI(MPI_Comm_size(PETSC_COMM_WORLD,&size)); 32c4762a1bSJed Brown 33c4762a1bSJed Brown /* Make copy of local array for doing updates */ 34*9566063dSJacob Faibussowitsch PetscCall(DMCreateLocalVector(da,&local)); 35c4762a1bSJed Brown 36c4762a1bSJed Brown /* determine starting point of each processor */ 37*9566063dSJacob Faibussowitsch PetscCall(VecGetOwnershipRange(global,&mybase,&myend)); 38c4762a1bSJed Brown 39c4762a1bSJed Brown /* Initialize the Array */ 40*9566063dSJacob Faibussowitsch PetscCall(VecGetLocalSize (global,&globalsize)); 41*9566063dSJacob Faibussowitsch PetscCall(VecGetArray (global,&globalptr)); 42c4762a1bSJed Brown 43c4762a1bSJed Brown for (i=0; i<globalsize; i++) { 44c4762a1bSJed Brown j = i + mybase; 45c4762a1bSJed Brown 46c4762a1bSJed Brown globalptr[i] = PetscSinReal((PETSC_PI*j*6)/((PetscReal)M) + 1.2 * PetscSinReal((PETSC_PI*j*2)/((PetscReal)M))) * 4+4; 47c4762a1bSJed Brown } 48c4762a1bSJed Brown 49*9566063dSJacob Faibussowitsch PetscCall(VecRestoreArray(global,&localptr)); 50c4762a1bSJed Brown 51c4762a1bSJed Brown /* Assign Parameters */ 52c4762a1bSJed Brown h= 1.0/M; 53c4762a1bSJed Brown k= h*h/2.2; 54*9566063dSJacob Faibussowitsch PetscCall(VecGetLocalSize(local,&localsize)); 55c4762a1bSJed Brown 56c4762a1bSJed Brown for (j=0; j<time_steps; j++) { 57c4762a1bSJed Brown 58c4762a1bSJed Brown /* Global to Local */ 59*9566063dSJacob Faibussowitsch PetscCall(DMGlobalToLocalBegin(da,global,INSERT_VALUES,local)); 60*9566063dSJacob Faibussowitsch PetscCall(DMGlobalToLocalEnd(da,global,INSERT_VALUES,local)); 61c4762a1bSJed Brown 62c4762a1bSJed Brown /*Extract local array */ 63*9566063dSJacob Faibussowitsch PetscCall(VecGetArray(local,&localptr)); 64*9566063dSJacob Faibussowitsch PetscCall(VecGetArray (global,&globalptr)); 65c4762a1bSJed Brown 66c4762a1bSJed Brown /* Update Locally - Make array of new values */ 67c4762a1bSJed Brown /* Note: I don't do anything for the first and last entry */ 68c4762a1bSJed Brown for (i=1; i< localsize-1; i++) { 69c4762a1bSJed Brown globalptr[i-1] = localptr[i] + (k/(h*h)) * (localptr[i+1]-2.0*localptr[i]+localptr[i-1]); 70c4762a1bSJed Brown } 71c4762a1bSJed Brown 72*9566063dSJacob Faibussowitsch PetscCall(VecRestoreArray (global,&globalptr)); 73*9566063dSJacob Faibussowitsch PetscCall(VecRestoreArray(local,&localptr)); 74c4762a1bSJed Brown 75c4762a1bSJed Brown /* View Wave */ 76c4762a1bSJed Brown /* Set Up Display to Show Heat Graph */ 77c4762a1bSJed Brown #if defined(PETSC_USE_SOCKET_VIEWER) 78*9566063dSJacob Faibussowitsch PetscCall(VecView(global,PETSC_VIEWER_SOCKET_WORLD)); 79c4762a1bSJed Brown #endif 80c4762a1bSJed Brown } 81c4762a1bSJed Brown 82*9566063dSJacob Faibussowitsch PetscCall(VecDestroy(&local)); 83*9566063dSJacob Faibussowitsch PetscCall(VecDestroy(&global)); 84*9566063dSJacob Faibussowitsch PetscCall(DMDestroy(&da)); 85*9566063dSJacob Faibussowitsch PetscCall(PetscFinalize()); 86b122ec5aSJacob Faibussowitsch return 0; 87c4762a1bSJed Brown } 88