Actual source code: matusfft.c


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

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

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

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

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

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

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

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

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

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

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

100:   /* NB: for now we use outdim for both x and y; this will change once a full USFFT is implemented */
101:   MatApply_USFFT_Private(A, &usfft->p_forward, FFTW_FORWARD, x,y);
102:   return 0;
103: }

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

109:   /* NB: for now we use outdim for both x and y; this will change once a full USFFT is implemented */
110:   MatApply_USFFT_Private(usfft, &usfft->p_backward, FFTW_BACKWARD, x,y);
111:   return 0;
112: }

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

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

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

131:    Collective

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

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

139:   Options Database Keys:
140: . -mat_usfft_plannerflags - set the FFTW planner flags

142:    Level: intermediate

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

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

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

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

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

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

230: #endif