FFT_Controller Class Reference

#include <newmatap.h>

Static Public Member Functions
static bool	ar_1d_ft (int PTS, Real *X, Real *Y)
static bool	CanFactor (int PTS)

Static Public Attributes
static bool	OnlyOldFFT

Detailed Description

Definition at line 106 of file newmatap.h.

Member Function Documentation

ar_1d_ft()

bool FFT_Controller::ar_1d_ft ( int  PTS, Real *  X, Real *  Y  )

static

Definition at line 146 of file newfft.cpp.

References REPORT, and square().

Referenced by FFT().

{
//    ARBITRARY RADIX ONE DIMENSIONAL FOURIER TRANSFORM

   REPORT

   int  F,J,N,NF,P,PMAX,P_SYM,P_TWO,Q,R,TWO_GRP;

   // NP is maximum number of squared factors allows PTS up to 2**32 at least
   // NQ is number of not-squared factors - increase if we increase PMAX
   const int NP = 16, NQ = 10;
   SimpleIntArray PP(NP), QQ(NQ);

   TWO_GRP=16; PMAX=19;

   // PMAX is the maximum factor size
   // TWO_GRP is the maximum power of 2 handled as a single factor
   // Doesn't take advantage of combining powers of 2 when calculating
   // number of factors

   if (PTS<=1) return true;
   N=PTS; P_SYM=1; F=2; P=0; Q=0;

   // P counts the number of squared factors
   // Q counts the number of the rest
   // R = 0 for no non-squared factors; 1 otherwise

   // FACTOR holds all the factors - non-squared ones in the middle
   //   - length is 2*P+Q
   // SYM also holds all the factors but with the non-squared ones
   //   multiplied together - length is 2*P+R
   // PP holds the values of the squared factors - length is P
   // QQ holds the values of the rest - length is Q

   // P_SYM holds the product of the squared factors

   // find the factors - load into PP and QQ
   while (N > 1)
   {
      bool fail = true;
      for (J=F; J<=PMAX; J++)
         if (N % J == 0) { fail = false; F=J; break; }
      if (fail || P >= NP || Q >= NQ) return false; // can't factor
      N /= F;
      if (N % F != 0) QQ[Q++] = F;
      else { N /= F; PP[P++] = F; P_SYM *= F; }
   }

   R = (Q == 0) ? 0 : 1;  // R = 0 if no not-squared factors, 1 otherwise

   NF = 2*P + Q;
   SimpleIntArray FACTOR(NF + 1), SYM(2*P + R);
   FACTOR[NF] = 0;                // we need this in the "combine powers of 2"

   // load into SYM and FACTOR
   for (J=0; J<P; J++)
      { SYM[J]=FACTOR[J]=PP[P-1-J]; FACTOR[P+Q+J]=SYM[P+R+J]=PP[J]; }

   if (Q>0)
   {
      REPORT
      for (J=0; J<Q; J++) FACTOR[P+J]=QQ[J];
      SYM[P]=PTS/square(P_SYM);
   }

   // combine powers of 2
   P_TWO = 1;
   for (J=0; J < NF; J++)
   {
      if (FACTOR[J]!=2) continue;
      P_TWO=P_TWO*2; FACTOR[J]=1;
      if (P_TWO<TWO_GRP && FACTOR[J+1]==2) continue;
      FACTOR[J]=P_TWO; P_TWO=1;
   }

   if (P==0) R=0;
   if (Q<=1) Q=0;

   // do the analysis
   GR_1D_FT(PTS,NF,FACTOR,X,Y);                 // the transform
   GR_1D_FS(PTS,2*P+R,Q,SYM,P_SYM,QQ,X,Y);      // the reshuffling

   return true;

}

CanFactor()

bool FFT_Controller::CanFactor ( int  PTS )

static

Definition at line 988 of file newfft.cpp.

References REPORT.

Referenced by FFT().

{
   REPORT
   const int NP = 16, NQ = 10, PMAX=19;

   if (PTS<=1) { REPORT return true; }

   int N = PTS, F = 2, P = 0, Q = 0;

   while (N > 1)
   {
      bool fail = true;
      for (int J = F; J <= PMAX; J++)
         if (N % J == 0) { fail = false; F=J; break; }
      if (fail || P >= NP || Q >= NQ) { REPORT return false; }
      N /= F;
      if (N % F != 0) Q++; else { N /= F; P++; }
   }

   return true;    // can factorise

}

Member Data Documentation

OnlyOldFFT

bool FFT_Controller::OnlyOldFFT

static

Definition at line 109 of file newmatap.h.

Referenced by FFT().

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The documentation for this class was generated from the following files:

• newmatap.h
• newfft.cpp