int main(int argc,char **argv)
{
Vec v,s,r,vecs[2]; /* vectors */
PetscInt i,start,end,n = 20;
PetscErrorCode ierr;
PetscScalar value;
PetscInitialize(&argc,&argv,(char*)0,help);
ierr = PetscOptionsGetInt(PETSC_NULL,"-n",&n,PETSC_NULL);CHKERRQ(ierr);
/*
Create multi-component vector with 2 components
*/
ierr = VecCreate(PETSC_COMM_WORLD,&v);CHKERRQ(ierr);
ierr = VecSetSizes(v,PETSC_DECIDE,n);CHKERRQ(ierr);
ierr = VecSetBlockSize(v,4);CHKERRQ(ierr);
ierr = VecSetFromOptions(v);CHKERRQ(ierr);
/*
Create double-component vectors
*/
ierr = VecCreate(PETSC_COMM_WORLD,&s);CHKERRQ(ierr);
ierr = VecSetSizes(s,PETSC_DECIDE,n/2);CHKERRQ(ierr);
ierr = VecSetBlockSize(s,2);CHKERRQ(ierr);
ierr = VecSetFromOptions(s);CHKERRQ(ierr);
ierr = VecDuplicate(s,&r);CHKERRQ(ierr);
vecs[0] = s;
vecs[1] = r;
/*
Set the vector values
*/
ierr = VecGetOwnershipRange(v,&start,&end);CHKERRQ(ierr);
for (i=start; i<end; i++) {
value = i;
ierr = VecSetValues(v,1,&i,&value,INSERT_VALUES);CHKERRQ(ierr);
}
/*
Get the components from the multi-component vector to the other vectors
*/
ierr = VecStrideGatherAll(v,vecs,INSERT_VALUES);CHKERRQ(ierr);
ierr = VecView(s,PETSC_VIEWER_STDOUT_WORLD);CHKERRQ(ierr);
ierr = VecView(r,PETSC_VIEWER_STDOUT_WORLD);CHKERRQ(ierr);
ierr = VecStrideScatterAll(vecs,v,ADD_VALUES);CHKERRQ(ierr);
ierr = VecView(v,PETSC_VIEWER_STDOUT_WORLD);CHKERRQ(ierr);
/*
Free work space. All PETSc objects should be destroyed when they
are no longer needed.
*/
ierr = VecDestroy(&v);CHKERRQ(ierr);
ierr = VecDestroy(&s);CHKERRQ(ierr);
ierr = VecDestroy(&r);CHKERRQ(ierr);
ierr = PetscFinalize();
return 0;
}
PetscInt main(PetscInt argc,char **args)
{
typedef enum {RANDOM, CONSTANT, TANH, NUM_FUNCS} FuncType;
const char *funcNames[NUM_FUNCS] = {"random", "constant", "tanh"};
Mat A, AA;
PetscMPIInt size;
PetscInt N,i, stencil=1,dof=3;
PetscInt dim[3] = {10,10,10}, ndim = 3;
Vec coords,x,y,z,xx, yy, zz;
Vec xxsplit[DOF], yysplit[DOF], zzsplit[DOF];
PetscReal h[3];
PetscScalar s;
PetscRandom rdm;
PetscReal norm, enorm;
PetscInt func;
FuncType function = TANH;
DM da, da1, coordsda;
PetscBool view_x = PETSC_FALSE, view_y = PETSC_FALSE, view_z = PETSC_FALSE;
PetscErrorCode ierr;
ierr = PetscInitialize(&argc,&args,(char *)0,help);CHKERRQ(ierr);
#if !defined(PETSC_USE_COMPLEX)
SETERRQ(PETSC_COMM_WORLD,PETSC_ERR_SUP, "This example requires complex numbers");
#endif
ierr = MPI_Comm_size(PETSC_COMM_WORLD, &size);CHKERRQ(ierr);
if (size != 1) SETERRQ(PETSC_COMM_WORLD,PETSC_ERR_SUP, "This is a uniprocessor example only!");
ierr = PetscOptionsBegin(PETSC_COMM_WORLD, PETSC_NULL, "USFFT Options", "ex27");CHKERRQ(ierr);
ierr = PetscOptionsEList("-function", "Function type", "ex27", funcNames, NUM_FUNCS, funcNames[function], &func, PETSC_NULL);CHKERRQ(ierr);
function = (FuncType) func;
ierr = PetscOptionsEnd();CHKERRQ(ierr);
ierr = PetscOptionsGetBool(PETSC_NULL,"-view_x",&view_x,PETSC_NULL);CHKERRQ(ierr);
ierr = PetscOptionsGetBool(PETSC_NULL,"-view_y",&view_y,PETSC_NULL);CHKERRQ(ierr);
ierr = PetscOptionsGetBool(PETSC_NULL,"-view_z",&view_z,PETSC_NULL);CHKERRQ(ierr);
ierr = PetscOptionsGetIntArray(PETSC_NULL,"-dim",dim,&ndim,PETSC_NULL);CHKERRQ(ierr);
// DMDA with the correct fiber dimension
ierr = DMDACreate3d(PETSC_COMM_SELF,DMDA_BOUNDARY_NONE,DMDA_BOUNDARY_NONE,DMDA_BOUNDARY_NONE,DMDA_STENCIL_STAR,
dim[0], dim[1], dim[2],
PETSC_DECIDE, PETSC_DECIDE, PETSC_DECIDE,
dof, stencil,
PETSC_NULL, PETSC_NULL, PETSC_NULL,
&da);
CHKERRQ(ierr);
// DMDA with fiber dimension 1 for split fields
ierr = DMDACreate3d(PETSC_COMM_SELF,DMDA_BOUNDARY_NONE,DMDA_BOUNDARY_NONE,DMDA_BOUNDARY_NONE,DMDA_STENCIL_STAR,
dim[0], dim[1], dim[2],
PETSC_DECIDE, PETSC_DECIDE, PETSC_DECIDE,
1, stencil,
PETSC_NULL, PETSC_NULL, PETSC_NULL,
&da1);
CHKERRQ(ierr);
// Coordinates
ierr = DMDAGetCoordinateDA(da, &coordsda);
ierr = DMGetGlobalVector(coordsda, &coords);CHKERRQ(ierr);
ierr = PetscObjectSetName((PetscObject) coords, "Grid coordinates");CHKERRQ(ierr);
for(i = 0, N = 1; i < 3; i++) {
h[i] = 1.0/dim[i];
PetscScalar *a;
ierr = VecGetArray(coords, &a);CHKERRQ(ierr);
PetscInt j,k,n = 0;
for(i = 0; i < 3; ++i) {
for(j = 0; j < dim[i]; ++j){
for(k = 0; k < 3; ++k) {
a[n] = j*h[i]; // coordinate along the j-th point in the i-th dimension
++n;
}
}
}
ierr = VecRestoreArray(coords, &a);CHKERRQ(ierr);
}
ierr = DMDASetCoordinates(da, coords);CHKERRQ(ierr);
ierr = VecDestroy(&coords);CHKERRQ(ierr);
// Work vectors
ierr = DMGetGlobalVector(da, &x);CHKERRQ(ierr);
ierr = PetscObjectSetName((PetscObject) x, "Real space vector");CHKERRQ(ierr);
ierr = DMGetGlobalVector(da, &xx);CHKERRQ(ierr);
ierr = PetscObjectSetName((PetscObject) xx, "Real space vector");CHKERRQ(ierr);
ierr = DMGetGlobalVector(da, &y);CHKERRQ(ierr);
ierr = PetscObjectSetName((PetscObject) y, "USFFT frequency space vector");CHKERRQ(ierr);
ierr = DMGetGlobalVector(da, &yy);CHKERRQ(ierr);
ierr = PetscObjectSetName((PetscObject) yy, "FFTW frequency space vector");CHKERRQ(ierr);
ierr = DMGetGlobalVector(da, &z);CHKERRQ(ierr);
ierr = PetscObjectSetName((PetscObject) z, "USFFT reconstructed vector");CHKERRQ(ierr);
ierr = DMGetGlobalVector(da, &zz);CHKERRQ(ierr);
ierr = PetscObjectSetName((PetscObject) zz, "FFTW reconstructed vector");CHKERRQ(ierr);
// Split vectors for FFTW
for(int ii = 0; ii < 3; ++ii) {
ierr = DMGetGlobalVector(da1, &xxsplit[ii]);CHKERRQ(ierr);
ierr = PetscObjectSetName((PetscObject) xxsplit[ii], "Real space split vector");CHKERRQ(ierr);
ierr = DMGetGlobalVector(da1, &yysplit[ii]);CHKERRQ(ierr);
ierr = PetscObjectSetName((PetscObject) yysplit[ii], "FFTW frequency space split vector");CHKERRQ(ierr);
ierr = DMGetGlobalVector(da1, &zzsplit[ii]);CHKERRQ(ierr);
ierr = PetscObjectSetName((PetscObject) zzsplit[ii], "FFTW reconstructed split vector");CHKERRQ(ierr);
}
ierr = PetscPrintf(PETSC_COMM_SELF, "%3-D: USFFT on vector of ");CHKERRQ(ierr);
for(i = 0, N = 1; i < 3; i++) {
ierr = PetscPrintf(PETSC_COMM_SELF, "dim[%d] = %d ",i,dim[i]);CHKERRQ(ierr);
N *= dim[i];
}
ierr = PetscPrintf(PETSC_COMM_SELF, "; total size %d \n",N);CHKERRQ(ierr);
if (function == RANDOM) {
ierr = PetscRandomCreate(PETSC_COMM_SELF, &rdm);CHKERRQ(ierr);
ierr = PetscRandomSetFromOptions(rdm);CHKERRQ(ierr);
ierr = VecSetRandom(x, rdm);CHKERRQ(ierr);
ierr = PetscRandomDestroy(&rdm);CHKERRQ(ierr);
}
else if (function == CONSTANT) {
ierr = VecSet(x, 1.0);CHKERRQ(ierr);
}
else if (function == TANH) {
PetscScalar *a;
ierr = VecGetArray(x, &a);CHKERRQ(ierr);
PetscInt j,k = 0;
for(i = 0; i < 3; ++i) {
for(j = 0; j < dim[i]; ++j) {
a[k] = tanh((j - dim[i]/2.0)*(10.0/dim[i]));
++k;
}
}
ierr = VecRestoreArray(x, &a);CHKERRQ(ierr);
}
if(view_x) {
ierr = VecView(x, PETSC_VIEWER_STDOUT_WORLD);CHKERRQ(ierr);
}
ierr = VecCopy(x,xx);CHKERRQ(ierr);
// Split xx
ierr = VecStrideGatherAll(xx,xxsplit, INSERT_VALUES);CHKERRQ(ierr); //YES! 'Gather' means 'split' (or maybe 'scatter'?)!
ierr = VecNorm(x,NORM_2,&norm);CHKERRQ(ierr);
ierr = PetscPrintf(PETSC_COMM_SELF, "|x|_2 = %g\n",norm);CHKERRQ(ierr);
/* create USFFT object */
ierr = MatCreateSeqUSFFT(da,da,&A);CHKERRQ(ierr);
/* create FFTW object */
ierr = MatCreateSeqFFTW(PETSC_COMM_SELF,3,dim,&AA);CHKERRQ(ierr);
/* apply USFFT and FFTW FORWARD "preemptively", so the fftw_plans can be reused on different vectors */
ierr = MatMult(A,x,z);CHKERRQ(ierr);
for(int ii = 0; ii < 3; ++ii) {
ierr = MatMult(AA,xxsplit[ii],zzsplit[ii]);CHKERRQ(ierr);
}
// Now apply USFFT and FFTW forward several (3) times
for (i=0; i<3; ++i){
ierr = MatMult(A,x,y);CHKERRQ(ierr);
for(int ii = 0; ii < 3; ++ii) {
ierr = MatMult(AA,xxsplit[ii],yysplit[ii]);CHKERRQ(ierr);
}
ierr = MatMultTranspose(A,y,z);CHKERRQ(ierr);
for(int ii = 0; ii < 3; ++ii) {
ierr = MatMult(AA,yysplit[ii],zzsplit[ii]);CHKERRQ(ierr);
}
}
// Unsplit yy
ierr = VecStrideScatterAll(yysplit, yy, INSERT_VALUES);CHKERRQ(ierr); //YES! 'Scatter' means 'collect' (or maybe 'gather'?)!
// Unsplit zz
ierr = VecStrideScatterAll(zzsplit, zz, INSERT_VALUES);CHKERRQ(ierr); //YES! 'Scatter' means 'collect' (or maybe 'gather'?)!
if(view_y) {
ierr = PetscPrintf(PETSC_COMM_WORLD, "y = \n");CHKERRQ(ierr);
ierr = VecView(y, PETSC_VIEWER_STDOUT_WORLD);CHKERRQ(ierr);
ierr = PetscPrintf(PETSC_COMM_WORLD, "yy = \n");CHKERRQ(ierr);
ierr = VecView(yy, PETSC_VIEWER_STDOUT_WORLD);CHKERRQ(ierr);
}
if(view_z) {
ierr = PetscPrintf(PETSC_COMM_WORLD, "z = \n");CHKERRQ(ierr);
ierr = VecView(z, PETSC_VIEWER_STDOUT_WORLD);CHKERRQ(ierr);
ierr = PetscPrintf(PETSC_COMM_WORLD, "zz = \n");CHKERRQ(ierr);
ierr = VecView(zz, PETSC_VIEWER_STDOUT_WORLD);CHKERRQ(ierr);
}
/* compare x and z. USFFT computes an unnormalized DFT, thus z = N*x */
s = 1.0/(PetscReal)N;
ierr = VecScale(z,s);CHKERRQ(ierr);
ierr = VecAXPY(x,-1.0,z);CHKERRQ(ierr);
ierr = VecNorm(x,NORM_1,&enorm);CHKERRQ(ierr);
ierr = PetscPrintf(PETSC_COMM_SELF, "|x-z| = %g\n",enorm);CHKERRQ(ierr);
/* compare xx and zz. FFTW computes an unnormalized DFT, thus zz = N*x */
s = 1.0/(PetscReal)N;
ierr = VecScale(zz,s);CHKERRQ(ierr);
ierr = VecAXPY(xx,-1.0,zz);CHKERRQ(ierr);
ierr = VecNorm(xx,NORM_1,&enorm);CHKERRQ(ierr);
ierr = PetscPrintf(PETSC_COMM_SELF, "|xx-zz| = %g\n",enorm);CHKERRQ(ierr);
/* compare y and yy: USFFT and FFTW results*/
ierr = VecNorm(y,NORM_2,&norm);CHKERRQ(ierr);
ierr = VecAXPY(y,-1.0,yy);CHKERRQ(ierr);
ierr = VecNorm(y,NORM_1,&enorm);CHKERRQ(ierr);
ierr = PetscPrintf(PETSC_COMM_SELF, "|y|_2 = %g\n",norm);CHKERRQ(ierr);
ierr = PetscPrintf(PETSC_COMM_SELF, "|y-yy| = %g\n",enorm);CHKERRQ(ierr);
/* compare z and zz: USFFT and FFTW results*/
ierr = VecNorm(z,NORM_2,&norm);CHKERRQ(ierr);
ierr = VecAXPY(z,-1.0,zz);CHKERRQ(ierr);
ierr = VecNorm(z,NORM_1,&enorm);CHKERRQ(ierr);
ierr = PetscPrintf(PETSC_COMM_SELF, "|z|_2 = %g\n",norm);CHKERRQ(ierr);
ierr = PetscPrintf(PETSC_COMM_SELF, "|z-zz| = %g\n",enorm);CHKERRQ(ierr);
/* free spaces */
ierr = DMRestoreGlobalVector(da,&x);CHKERRQ(ierr);
ierr = DMRestoreGlobalVector(da,&xx);CHKERRQ(ierr);
ierr = DMRestoreGlobalVector(da,&y);CHKERRQ(ierr);
ierr = DMRestoreGlobalVector(da,&yy);CHKERRQ(ierr);
ierr = DMRestoreGlobalVector(da,&z);CHKERRQ(ierr);
ierr = DMRestoreGlobalVector(da,&zz);CHKERRQ(ierr);
ierr = PetscFinalize();
return 0;
}
