Date: 2022-03-04T17:38:25+00:00

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
     27:   PetscScalar    *r_array, *y_array;
     28:   Mat_USFFT* = (Mat_USFFT*)(A->data);
     29: #endif

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

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

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

     82: #if 0
     83: PetscErrorCode MatUSFFT_ProjectOnBattleLemarie_Private(Vec x,double *r)
     84: /* Project onto the Battle-Lemarie function centered around r */
     85: {
     87:   PetscScalar    *x_array, *y_array;

     90:   return(0);
     91: } /* MatUSFFT_ProjectOnBattleLemarie_Private() */

     93: PetscErrorCode MatInterpolate_USFFT_Private(Vec x,Vec y)
     94: {
     96:   PetscScalar    *x_array, *y_array;

     99:   return(0);
    100: } /* MatInterpolate_USFFT_Private() */

    102: PetscErrorCode MatMult_SeqUSFFT(Mat A,Vec x,Vec y)
    103: {
    105:   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(A, &usfft->p_forward, FFTW_FORWARD, x,y);
    110:   return(0);
    111: }

    113: PetscErrorCode MatMultTranspose_SeqUSFFT(Mat A,Vec x,Vec y)
    114: {
    116:   Mat_USFFT      *usfft = (Mat_USFFT*)A->data;

    119:   /* NB: for now we use outdim for both x and y; this will change once a full USFFT is implemented */
    120:   MatApply_USFFT_Private(usfft, &usfft->p_backward, FFTW_BACKWARD, x,y);
    121:   return(0);
    122: }

    124: PetscErrorCode MatDestroy_SeqUSFFT(Mat A)
    125: {
    126:   Mat_USFFT      *usfft = (Mat_USFFT*)A->data;

    130:   fftw_destroy_plan(usfft->p_forward);
    131:   fftw_destroy_plan(usfft->p_backward);
    132:   PetscFree(usfft->indim);
    133:   PetscFree(usfft->outdim);
    134:   PetscFree(usfft);
    135:   PetscObjectChangeTypeName((PetscObject)A,0);
    136:   return(0);
    137: } /* MatDestroy_SeqUSFFT() */

    139: /*@C
    140:       MatCreateSeqUSFFT - Creates a matrix object that provides sequential USFFT
    141:   via the external package FFTW

    143:    Collective

    145:    Input Parameter:
    146: .   da - geometry of the domain encoded by a DMDA

    148:    Output Parameter:
    149: .   A  - the matrix

    151:   Options Database Keys:
    152: . -mat_usfft_plannerflags - set the FFTW planner flags

    154:    Level: intermediate

    156: @*/
    157: PetscErrorCode  MatCreateSeqUSFFT(Vec sampleCoords, DMDA freqDA, Mat *A)
    158: {
    160:   Mat_USFFT      *usfft;
    161:   PetscInt       m,n,M,N,i;
    162:   const char     *p_flags[]={"FFTW_ESTIMATE","FFTW_MEASURE","FFTW_PATIENT","FFTW_EXHAUSTIVE"};
    163:   PetscBool      flg;
    164:   PetscInt       p_flag;
    165:   PetscInt       dof, dim, freqSizes[3];
    166:   MPI_Comm       comm;
    167:   PetscInt       size;

    170:   PetscObjectGetComm((PetscObject)inda, &comm);
    171:   MPI_Comm_size(comm, &size);
    172:   if (size > 1) SETERRQ(comm,PETSC_ERR_USER, "Parallel DMDA (in) not yet supported by USFFT");
    173:   PetscObjectGetComm((PetscObject)outda, &comm);
    174:   MPI_Comm_size(comm, &size);
    175:   if (size > 1) SETERRQ(comm,PETSC_ERR_USER, "Parallel DMDA (out) not yet supported by USFFT");
    176:   MatCreate(comm,A);
    177:   PetscNewLog(*A,&usfft);
    178:   (*A)->data   = (void*)usfft;
    179:   usfft->inda  = inda;
    180:   usfft->outda = outda;
    181:   /* inda */
    182:   DMDAGetInfo(usfft->inda, &ndim, dim+0, dim+1, dim+2, NULL, NULL, NULL, &dof, NULL, NULL, NULL);
    183:   if (ndim <= 0) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_USER,"ndim %d must be > 0",ndim);
    184:   if (dof <= 0) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_USER,"dof %d must be > 0",dof);
    185:   usfft->ndim   = ndim;
    186:   usfft->dof    = dof;
    187:   usfft->freqDA = freqDA;
    188:   /* NB: we reverse the freq and resample DMDA sizes, since the DMDA ordering (natural on x-y-z, with x varying the fastest)
    189:      is the order opposite of that assumed by FFTW: z varying the fastest */
    190:   PetscMalloc1(usfft->ndim+1,&usfft->indim);
    191:   for (i = usfft->ndim; i > 0; --i) usfft->indim[usfft->ndim-i] = dim[i-1];

    193:   /* outda */
    194:   DMDAGetInfo(usfft->outda, &ndim, dim+0, dim+1, dim+2, NULL, NULL, NULL, &dof, NULL, NULL, NULL);
    195:   if (ndim != usfft->ndim) SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_USER,"in and out DMDA dimensions must match: %d != %d",usfft->ndim, ndim);
    196:   if (dof != usfft->dof) SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_USER,"in and out DMDA dof must match: %d != %d",usfft->dof, dof);
    197:   /* Store output dimensions */
    198:   /* NB: we reverse the DMDA dimensions, since the DMDA ordering (natural on x-y-z, with x varying the fastest)
    199:      is the order opposite of that assumed by FFTW: z varying the fastest */
    200:   PetscMalloc1(usfft->ndim+1,&usfft->outdim);
    201:   for (i = usfft->ndim; i > 0; --i) usfft->outdim[usfft->ndim-i] = dim[i-1];

    203:   /* TODO: Use the new form of DMDACreate() */
    204: #if 0
    205:   DMDACreate(comm,usfft->dim, DMDA_NONPERIODIC, DMDA_STENCIL_STAR, usfft->freqSizes[0], usfft->freqSizes[1], usfft->freqSizes[2],
    206:                     PETSC_DECIDE, PETSC_DECIDE, PETSC_DECIDE, dof, 0, NULL, NULL, NULL,  0, &(usfft->resampleDA));
    207: #endif
    208:   DMDAGetVec(usfft->resampleDA, usfft->resample);

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

    212:   /* CONTINUE: recalculate matrix sizes based on the connectivity "Sieve" */
    213:   /* mat sizes */
    214:   m = 1; n = 1;
    215:   for (i=0; i<usfft->ndim; i++) {
    216:     if (usfft->indim[i] <= 0) SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_USER,"indim[%d]=%d must be > 0",i,usfft->indim[i]);
    217:     if (usfft->outdim[i] <= 0) SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_USER,"outdim[%d]=%d must be > 0",i,usfft->outdim[i]);
    218:     n *= usfft->indim[i];
    219:     m *= usfft->outdim[i];
    220:   }
    221:   N        = n*usfft->dof;
    222:   M        = m*usfft->dof;
    223:   MatSetSizes(*A,M,N,M,N); /* "in size" is the number of columns, "out size" is the number of rows" */
    224:   PetscObjectChangeTypeName((PetscObject)*A,MATSEQUSFFT);
    225:   usfft->m = m; usfft->n = n; usfft->M = M; usfft->N = N;
    226:   /* FFTW */
    227:   usfft->p_forward  = 0;
    228:   usfft->p_backward = 0;
    229:   usfft->p_flag     = FFTW_ESTIMATE;
    230:   /* set Mat ops */
    231:   (*A)->ops->mult          = MatMult_SeqUSFFT;
    232:   (*A)->ops->multtranspose = MatMultTranspose_SeqUSFFT;
    233:   (*A)->assembled          = PETSC_TRUE;
    234:   (*A)->ops->destroy       = MatDestroy_SeqUSFFT;
    235:   /* get runtime options */
    236:   PetscOptionsBegin(((PetscObject)(*A))->comm,((PetscObject)(*A))->prefix,"USFFT Options","Mat");
    237:   PetscOptionsEList("-mat_usfft_fftw_plannerflags","Planner Flags","None",p_flags,4,p_flags[0],&p_flag,&flg);
    238:   if (flg) usfft->p_flag = (unsigned)p_flag;
    239:   PetscOptionsEnd();
    240:   return(0);
    241: } /* MatCreateSeqUSFFT() */

    243: #endif