Date: 2015-10-02T22:13:54+00:00

Actual source code: matusfft.c
petsc-3.6.2 2015-10-02
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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