Actual source code: matusfft.c

petsc-3.5.2 2014-09-08
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  2: /*
  3:     Provides an implementation of the Unevenly Sampled FFT algorithm as a Mat.
  4:     Testing examples can be found in ~/src/mat/examples/tests FIX: should these be moved to dm/da/examples/tests?
  5: */

  7: #include <petsc-private/matimpl.h>          /*I "petscmat.h" I*/
  8: #include <petscdmda.h>                  /*I "petscdmda.h"  I*/ /* Unlike equispaced FFT, USFFT requires geometric information encoded by a DMDA */
  9: #include <fftw3.h>

 11: typedef struct {
 12:   PetscInt  dim;
 13:   Vec       sampleCoords;
 14:   PetscInt  dof;
 15:   DM        freqDA;            /* frequency DMDA */
 16:   PetscInt  *freqSizes;        /* sizes of the frequency DMDA, one per each dim */
 17:   DM        resampleDa;        /* the Battle-Lemarie interpolant DMDA */
 18:   Vec       resample;          /* Vec of samples, one per dof per sample point */
 19:   fftw_plan p_forward,p_backward;
 20:   unsigned  p_flag;      /* planner flags, FFTW_ESTIMATE,FFTW_MEASURE, FFTW_PATIENT, FFTW_EXHAUSTIVE */
 21: } Mat_USFFT;


 26: PetscErrorCode MatApply_USFFT_Private(Mat A, fftw_plan *plan, int direction, Vec x,Vec y)
 27: {
 28: #if 0
 30:   PetscScalar    *r_array, *y_array;
 31:   Mat_USFFT* = (Mat_USFFT*)(A->data);
 32: #endif

 35: #if 0
 36:   /* resample x to usfft->resample */
 37:   MatResample_USFFT_Private(A, x);

 39:   /* NB: for now we use outdim for both x and y; this will change once a full USFFT is implemented */
 40:   VecGetArray(usfft->resample,&r_array);
 41:   VecGetArray(y,&y_array);
 42:   if (!*plan) { /* create a plan then execute it*/
 43:     if (usfft->dof == 1) {
 44: #if defined(PETSC_DEBUG_USFFT)
 45:       PetscPrintf(PetscObjectComm((PetscObject)A), "direction = %d, usfft->ndim = %d\n", direction, usfft->ndim);
 46:       for (int ii = 0; ii < usfft->ndim; ++ii) {
 47:         PetscPrintf(PetscObjectComm((PetscObject)A), "usfft->outdim[%d] = %d\n", ii, usfft->outdim[ii]);
 48:       }
 49: #endif

 51:       switch (usfft->dim) {
 52:       case 1:
 53:         *plan = fftw_plan_dft_1d(usfft->outdim[0],(fftw_complex*)x_array,(fftw_complex*)y_array,direction,usfft->p_flag);
 54:         break;
 55:       case 2:
 56:         *plan = fftw_plan_dft_2d(usfft->outdim[0],usfft->outdim[1],(fftw_complex*)x_array,(fftw_complex*)y_array,direction,usfft->p_flag);
 57:         break;
 58:       case 3:
 59:         *plan = fftw_plan_dft_3d(usfft->outdim[0],usfft->outdim[1],usfft->outdim[2],(fftw_complex*)x_array,(fftw_complex*)y_array,direction,usfft->p_flag);
 60:         break;
 61:       default:
 62:         *plan = fftw_plan_dft(usfft->ndim,usfft->outdim,(fftw_complex*)x_array,(fftw_complex*)y_array,direction,usfft->p_flag);
 63:         break;
 64:       }
 65:       fftw_execute(*plan);
 66:     } /* if (dof == 1) */
 67:     else { /* if (dof > 1) */
 68:       *plan = fftw_plan_many_dft(/*rank*/usfft->ndim, /*n*/usfft->outdim, /*howmany*/usfft->dof,
 69:                                  (fftw_complex*)x_array, /*nembed*/usfft->outdim, /*stride*/usfft->dof, /*dist*/1,
 70:                                  (fftw_complex*)y_array, /*nembed*/usfft->outdim, /*stride*/usfft->dof, /*dist*/1,
 71:                                  /*sign*/direction, /*flags*/usfft->p_flag);
 72:       fftw_execute(*plan);
 73:     } /* if (dof > 1) */
 74:   } /* if (!*plan) */
 75:   else {  /* if (*plan) */
 76:     /* use existing plan */
 77:     fftw_execute_dft(*plan,(fftw_complex*)x_array,(fftw_complex*)y_array);
 78:   }
 79:   VecRestoreArray(y,&y_array);
 80:   VecRestoreArray(x,&x_array);
 81: #endif
 82:   return(0);
 83: } /* MatApply_USFFT_Private() */

 85: #if 0
 88: PetscErrorCode Mat_USFFT_ProjectOnBattleLemarie_Private(Vec x,double *r)
 89: /* Project onto the Battle-Lemarie function centered around r */
 90: {
 92:   PetscScalar    *x_array, *y_array;

 95:   return(0);
 96: } /* Mat_USFFT_ProjectOnBattleLemarie_Private() */

100: PetscErrorCode MatInterpolate_USFFT_Private(Vec x,Vec y)
101: {
103:   PetscScalar    *x_array, *y_array;

106:   return(0);
107: } /* MatInterpolate_USFFT_Private() */


112: PetscErrorCode MatMult_SeqUSFFT(Mat A,Vec x,Vec y)
113: {
115:   Mat_USFFT      *usfft = (Mat_USFFT*)A->data;

118:   /* NB: for now we use outdim for both x and y; this will change once a full USFFT is implemented */
119:   MatApply_USFFT_Private(A, &usfft->p_forward, FFTW_FORWARD, x,y);
120:   return(0);
121: }

125: PetscErrorCode MatMultTranspose_SeqUSFFT(Mat A,Vec x,Vec y)
126: {
128:   Mat_USFFT      *usfft = (Mat_USFFT*)A->data;

131:   /* NB: for now we use outdim for both x and y; this will change once a full USFFT is implemented */
132:   MatApply_USFFT_Private(usfft, &usfft->p_backward, FFTW_BACKWARD, x,y);
133:   return(0);
134: }

138: PetscErrorCode MatDestroy_SeqUSFFT(Mat A)
139: {
140:   Mat_USFFT      *usfft = (Mat_USFFT*)A->data;

144:   fftw_destroy_plan(usfft->p_forward);
145:   fftw_destroy_plan(usfft->p_backward);
146:   PetscFree(usfft->indim);
147:   PetscFree(usfft->outdim);
148:   PetscFree(usfft);
149:   PetscObjectChangeTypeName((PetscObject)A,0);
150:   return(0);
151: } /* MatDestroy_SeqUSFFT() */


156: /*@C
157:       MatCreateSeqUSFFT - Creates a matrix object that provides sequential USFFT
158:   via the external package FFTW

160:    Collective on MPI_Comm

162:    Input Parameter:
163: +   da - geometry of the domain encoded by a DMDA

165:    Output Parameter:
166: .   A  - the matrix

168:   Options Database Keys:
169: + -mat_usfft_plannerflags - set the FFTW planner flags

171:    Level: intermediate

173: @*/
174: PetscErrorCode  MatCreateSeqUSFFT(Vec sampleCoords, DMDA freqDA, Mat *A)
175: {
177:   Mat_USFFT      *usfft;
178:   PetscInt       m,n,M,N,i;
179:   const char     *p_flags[]={"FFTW_ESTIMATE","FFTW_MEASURE","FFTW_PATIENT","FFTW_EXHAUSTIVE"};
180:   PetscBool      flg;
181:   PetscInt       p_flag;
182:   PetscInt       dof, dim, freqSizes[3];
183:   MPI_Comm       comm;
184:   PetscInt       size;

187:   PetscObjectGetComm((PetscObject)inda, &comm);
188:   MPI_Comm_size(comm, &size);
189:   if (size > 1) SETERRQ(comm,PETSC_ERR_USER, "Parallel DMDA (in) not yet supported by USFFT");
190:   PetscObjectGetComm((PetscObject)outda, &comm);
191:   MPI_Comm_size(comm, &size);
192:   if (size > 1) SETERRQ(comm,PETSC_ERR_USER, "Parallel DMDA (out) not yet supported by USFFT");
193:   MatCreate(comm,A);
194:   PetscNewLog(*A,&usfft);
195:   (*A)->data   = (void*)usfft;
196:   usfft->inda  = inda;
197:   usfft->outda = outda;
198:   /* inda */
199:   DMDAGetInfo(usfft->inda, &ndim, dim+0, dim+1, dim+2, NULL, NULL, NULL, &dof, NULL, NULL, NULL);
200:   if (ndim <= 0) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_USER,"ndim %d must be > 0",ndim);
201:   if (dof <= 0) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_USER,"dof %d must be > 0",dof);
202:   usfft->ndim   = ndim;
203:   usfft->dof    = dof;
204:   usfft->freqDA = freqDA;
205:   /* NB: we reverse the freq and resample DMDA sizes, since the DMDA ordering (natural on x-y-z, with x varying the fastest)
206:      is the order opposite of that assumed by FFTW: z varying the fastest */
207:   PetscMalloc1((usfft->ndim+1),&usfft->indim);
208:   for (i = usfft->ndim; i > 0; --i) usfft->indim[usfft->ndim-i] = dim[i-1];

210:   /* outda */
211:   DMDAGetInfo(usfft->outda, &ndim, dim+0, dim+1, dim+2, NULL, NULL, NULL, &dof, NULL, NULL, NULL);
212:   if (ndim != usfft->ndim) SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_USER,"in and out DMDA dimensions must match: %d != %d",usfft->ndim, ndim);
213:   if (dof != usfft->dof) SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_USER,"in and out DMDA dof must match: %d != %d",usfft->dof, dof);
214:   /* Store output dimensions */
215:   /* NB: we reverse the DMDA dimensions, since the DMDA ordering (natural on x-y-z, with x varying the fastest)
216:      is the order opposite of that assumed by FFTW: z varying the fastest */
217:   PetscMalloc1((usfft->ndim+1),&usfft->outdim);
218:   for (i = usfft->ndim; i > 0; --i) usfft->outdim[usfft->ndim-i] = dim[i-1];

220:   /* TODO: Use the new form of DMDACreate() */
221: #if 0
222:   DMDACreate(comm,usfft->dim, DMDA_NONPERIODIC, DMDA_STENCIL_STAR, usfft->freqSizes[0], usfft->freqSizes[1], usfft->freqSizes[2],
223:                     PETSC_DECIDE, PETSC_DECIDE, PETSC_DECIDE, dof, 0, NULL, NULL, NULL,  0, &(usfft->resampleDA));
224: #endif
225:   DMDAGetVec(usfft->resampleDA, usfft->resample);


228:   /* CONTINUE: Need to build the connectivity "Sieve" attaching sample points to the resample points they are close to */

230:   /* CONTINUE: recalculate matrix sizes based on the connectivity "Sieve" */
231:   /* mat sizes */
232:   m = 1; n = 1;
233:   for (i=0; i<usfft->ndim; i++) {
234:     if (usfft->indim[i] <= 0) SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_USER,"indim[%d]=%d must be > 0",i,usfft->indim[i]);
235:     if (usfft->outdim[i] <= 0) SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_USER,"outdim[%d]=%d must be > 0",i,usfft->outdim[i]);
236:     n *= usfft->indim[i];
237:     m *= usfft->outdim[i];
238:   }
239:   N        = n*usfft->dof;
240:   M        = m*usfft->dof;
241:   MatSetSizes(*A,M,N,M,N); /* "in size" is the number of columns, "out size" is the number of rows" */
242:   PetscObjectChangeTypeName((PetscObject)*A,MATSEQUSFFT);
243:   usfft->m = m; usfft->n = n; usfft->M = M; usfft->N = N;
244:   /* FFTW */
245:   usfft->p_forward  = 0;
246:   usfft->p_backward = 0;
247:   usfft->p_flag     = FFTW_ESTIMATE;
248:   /* set Mat ops */
249:   (*A)->ops->mult          = MatMult_SeqUSFFT;
250:   (*A)->ops->multtranspose = MatMultTranspose_SeqUSFFT;
251:   (*A)->assembled          = PETSC_TRUE;
252:   (*A)->ops->destroy       = MatDestroy_SeqUSFFT;
253:   /* get runtime options */
254:   PetscOptionsBegin(((PetscObject)(*A))->comm,((PetscObject)(*A))->prefix,"USFFT Options","Mat");
255:   PetscOptionsEList("-mat_usfft_fftw_plannerflags","Planner Flags","None",p_flags,4,p_flags[0],&p_flag,&flg);
256:   if (flg) usfft->p_flag = (unsigned)p_flag;
257:   PetscOptionsEnd();
258:   return(0);
259: } /* MatCreateSeqUSFFT() */

261: #endif