Actual source code: matusfft.c

  1: /*
  2:     Provides an implementation of the Unevenly Sampled FFT algorithm as a Mat.
  3:     Testing examples can be found in ~/src/mat/tests FIX: should these be moved to dm/da/tests?
  4: */

  6: #include <petsc/private/matimpl.h>
  7: #include <petscdmda.h>
  8: #include <fftw3.h>

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

 22: PetscErrorCode MatApply_USFFT_Private(Mat A, fftw_plan *plan, int direction, Vec x, Vec y)
 23: {
 24: #if 0
 25:   PetscScalar    *r_array, *y_array;
 26:   Mat_USFFT* = (Mat_USFFT*)(A->data);
 27: #endif

 29: #if 0
 30:   /* resample x to usfft->resample */
 31:   MatResample_USFFT_Private(A, x);

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

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

 79: #if 0
 80: PetscErrorCode MatUSFFT_ProjectOnBattleLemarie_Private(Vec x,double *r)
 81: /* Project onto the Battle-Lemarie function centered around r */
 82: {
 83:   PetscScalar    *x_array, *y_array;

 85:   return 0;
 86: } /* MatUSFFT_ProjectOnBattleLemarie_Private() */

 88: PetscErrorCode MatInterpolate_USFFT_Private(Vec x,Vec y)
 89: {
 90:   PetscScalar    *x_array, *y_array;

 92:   return 0;
 93: } /* MatInterpolate_USFFT_Private() */

 95: PetscErrorCode MatMult_SeqUSFFT(Mat A,Vec x,Vec y)
 96: {
 97:   Mat_USFFT      *usfft = (Mat_USFFT*)A->data;

 99:   /* NB: for now we use outdim for both x and y; this will change once a full USFFT is implemented */
100:   MatApply_USFFT_Private(A, &usfft->p_forward, FFTW_FORWARD, x,y);
101:   return 0;
102: }

104: PetscErrorCode MatMultTranspose_SeqUSFFT(Mat A,Vec x,Vec y)
105: {
106:   Mat_USFFT      *usfft = (Mat_USFFT*)A->data;

108:   /* NB: for now we use outdim for both x and y; this will change once a full USFFT is implemented */
109:   MatApply_USFFT_Private(usfft, &usfft->p_backward, FFTW_BACKWARD, x,y);
110:   return 0;
111: }

113: PetscErrorCode MatDestroy_SeqUSFFT(Mat A)
114: {
115:   Mat_USFFT      *usfft = (Mat_USFFT*)A->data;

117:   fftw_destroy_plan(usfft->p_forward);
118:   fftw_destroy_plan(usfft->p_backward);
119:   PetscFree(usfft->indim);
120:   PetscFree(usfft->outdim);
121:   PetscFree(usfft);
122:   PetscObjectChangeTypeName((PetscObject)A,0);
123:   return 0;
124: }

126: /*@C
127:       MatCreateSeqUSFFT - Creates a matrix object that provides sequential USFFT
128:   via the external package FFTW

130:    Collective

132:    Input Parameter:
133: .   da - geometry of the domain encoded by a `DMDA`

135:    Output Parameter:
136: .   A  - the matrix

138:   Options Database Key:
139: . -mat_usfft_plannerflags - set the FFTW planner flags

141:    Level: intermediate

143: .seealso: `Mat`, `Vec`, `DMDA`, `DM`
144: @*/
145: PetscErrorCode  MatCreateSeqUSFFT(Vec sampleCoords, DMDA freqDA, Mat *A)
146: {
147:   Mat_USFFT      *usfft;
148:   PetscInt       m,n,M,N,i;
149:   const char     *p_flags[]={"FFTW_ESTIMATE","FFTW_MEASURE","FFTW_PATIENT","FFTW_EXHAUSTIVE"};
150:   PetscBool      flg;
151:   PetscInt       p_flag;
152:   PetscInt       dof, dim, freqSizes[3];
153:   MPI_Comm       comm;
154:   PetscInt       size;

156:   PetscObjectGetComm((PetscObject)inda, &comm);
157:   MPI_Comm_size(comm, &size);
159:   PetscObjectGetComm((PetscObject)outda, &comm);
160:   MPI_Comm_size(comm, &size);
162:   MatCreate(comm,A);
163:   PetscNew(&usfft);
164:   (*A)->data   = (void*)usfft;
165:   usfft->inda  = inda;
166:   usfft->outda = outda;
167:   /* inda */
168:   DMDAGetInfo(usfft->inda, &ndim, dim+0, dim+1, dim+2, NULL, NULL, NULL, &dof, NULL, NULL, NULL);
171:   usfft->ndim   = ndim;
172:   usfft->dof    = dof;
173:   usfft->freqDA = freqDA;
174:   /* NB: we reverse the freq and resample DMDA sizes, since the DMDA ordering (natural on x-y-z, with x varying the fastest)
175:      is the order opposite of that assumed by FFTW: z varying the fastest */
176:   PetscMalloc1(usfft->ndim+1,&usfft->indim);
177:   for (i = usfft->ndim; i > 0; --i) usfft->indim[usfft->ndim-i] = dim[i-1];

179:   /* outda */
180:   DMDAGetInfo(usfft->outda, &ndim, dim+0, dim+1, dim+2, NULL, NULL, NULL, &dof, NULL, NULL, NULL);
183:   /* Store output dimensions */
184:   /* NB: we reverse the DMDA dimensions, since the DMDA ordering (natural on x-y-z, with x varying the fastest)
185:      is the order opposite of that assumed by FFTW: z varying the fastest */
186:   PetscMalloc1(usfft->ndim+1,&usfft->outdim);
187:   for (i = usfft->ndim; i > 0; --i) usfft->outdim[usfft->ndim-i] = dim[i-1];

189:   /* TODO: Use the new form of DMDACreate() */
190:   #if 0
191:   PetscCall(DMDACreate(comm,usfft->dim, DMDA_NONPERIODIC, DMDA_STENCIL_STAR, usfft->freqSizes[0], usfft->freqSizes[1], usfft->freqSizes[2],
192:                        PETSC_DECIDE, PETSC_DECIDE, PETSC_DECIDE, dof, 0, NULL, NULL, NULL,  0, &(usfft->resampleDA)));
193:   #endif
194:   DMDAGetVec(usfft->resampleDA, usfft->resample);

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

198:   /* CONTINUE: recalculate matrix sizes based on the connectivity "Sieve" */
199:   /* mat sizes */
200:   m = 1; n = 1;
201:   for (i=0; i<usfft->ndim; i++) {
204:     n *= usfft->indim[i];
205:     m *= usfft->outdim[i];
206:   }
207:   N        = n*usfft->dof;
208:   M        = m*usfft->dof;
209:   MatSetSizes(*A,M,N,M,N); /* "in size" is the number of columns, "out size" is the number of rows" */
210:   PetscObjectChangeTypeName((PetscObject)*A,MATSEQUSFFT);
211:   usfft->m = m; usfft->n = n; usfft->M = M; usfft->N = N;
212:   /* FFTW */
213:   usfft->p_forward  = 0;
214:   usfft->p_backward = 0;
215:   usfft->p_flag     = FFTW_ESTIMATE;
216:   /* set Mat ops */
217:   (*A)->ops->mult          = MatMult_SeqUSFFT;
218:   (*A)->ops->multtranspose = MatMultTranspose_SeqUSFFT;
219:   (*A)->assembled          = PETSC_TRUE;
220:   (*A)->ops->destroy       = MatDestroy_SeqUSFFT;
221:   /* get runtime options */
222:   PetscOptionsBegin(((PetscObject)(*A))->comm,((PetscObject)(*A))->prefix,"USFFT Options","Mat");
223:   PetscOptionsEList("-mat_usfft_fftw_plannerflags","Planner Flags","None",p_flags,4,p_flags[0],&p_flag,&flg);
224:   if (flg) usfft->p_flag = (unsigned)p_flag;
225:   PetscOptionsEnd();
226:   return 0;
227: } /* MatCreateSeqUSFFT() */

229: #endif