topic Re: FFTInitAlloc arguments? in Intel® Integrated Performance Primitives

FFTInitAlloc arguments?

xorvax — Wed, 29 Dec 2004 04:21:43 GMT

I'd like to use FFT in my program (Delphi), but I don't know how to determinate arguments of FFTInitAlloc function (IppStatus ippiFFTInitAlloc_R_32s (IppiFFTSpec_R_32s** pFFTSpec,
int orderX, int orderY, int flag, IppHintAlgorithm hint)), especially - orderX, orderY. Some Delphi sample code how to use FFT.
thanks

Re: FFTInitAlloc arguments?

seiji-torigoe — Wed, 29 Dec 2004 08:54:08 GMT

Example 10-1 Fast Fourier Transform of a Real Image (p.10-12)
Maybe
ImageSize = 64 = 8 * 8; 8 := 2 * 2 * 2; orderX = 3; orderY =3; ???

Ex.

type IppHintAlgorithm = (
ippAlgHintNone,
ippAlgHintFast,
ippAlgHintAccurate
);

const IPP_FFT_DIV_FWD_BY_N = 1;
const IPP_FFT_DIV_INV_BY_N = 2;
const IPP_FFT_DIV_BY_SQRTN = 4;
const IPP_FFT_NODIV_BY_ANY = 8;

function ippiFFTInitAlloc_R_32f(
var pFFTSpec: Pointer;
orderX, orderY, flag: Integer;
hint: IppHintAlgorithm): Integer;
stdcall; external 'ippi20.dll';

function ippiFFTFwd_RToPack_32f_C1R(
pSrc: PSingle;
srcStep: Integer;
pDst: PSingle;
dstStep: Integer;
pFFTSpec: Pointer;
pBuffer: PByte): Integer;
stdcall; external 'ippi20.dll';

function ippiFFTFree_R_32f(pFFTSpec: Pointer): Integer;
stdcall; external 'ippi20.dll';

procedure TForm1.Button1Click(Sender: TObject);
var src, dst: array of Single;
var spec: Pointer;
begin
SetLength(src, 64); FillChar(src[0], 64*SizeOf(Single), 0);
SetLength(dst, 64);
src[0] := -3.0; src[9] := 1.0;
ippiFFTInitAlloc_R_32f(spec, 3, 3, IPP_FFT_DIV_INV_BY_N, ippAlgHintAccurate);
ippiFFTFwd_RToPack_32f_C1R(@src[0], 8*4, @dst[0], 8*4, spec, nil);
ippiFFTFree_R_32f(spec);
dst := nil;
src := nil;
end;

Message Edited by Seiji-Torigoe on 12-28-2004 04:58 PM

Re: FFTInitAlloc arguments?

xorvax — Fri, 31 Dec 2004 03:08:14 GMT

Could you explain me, please,whyyou usethese values:

const IPP_FFT_DIV_FWD_BY_N = 1;
const IPP_FFT_DIV_INV_BY_N = 2;
const IPP_FFT_DIV_BY_SQRTN = 4;
const IPP_FFT_NODIV_BY_ANY = 8; ???

Because it's defined:

Value of flag Argument Normalization Factors
Forward Transform Inverse Transform
IPP_FFT_DIV_FWD_BY_N 1/MN 1
IPP_FFT_DIV_INV_BY_N 1 1/MN
IPP_FFT_DIV_BY_SQRTN 1/sqrt(MN) 1/sqrt(MN)
IPP_FFT_NODIV_BY_ANY 1 1

thanks

Re: FFTInitAlloc arguments?

seiji-torigoe — Thu, 06 Jan 2005 10:15:10 GMT

I'm sorry.
As for fast Fourier transform, I am not familiar.
I only changed the sample of the manual into delphi.

Re: FFTInitAlloc arguments?

xorvax — Thu, 06 Jan 2005 18:06:32 GMT

Where can I find this Delphi manual?

Re: FFTInitAlloc arguments?

seiji-torigoe — Fri, 07 Jan 2005 09:36:48 GMT

???
The manual is "Ippiman.pdf"
The document Number is "A70805-014"
The page is "10-12"
The code is "Example 10-1 Fast Fourier Transform of a Real Image"
I only changed this.

Re: FFTInitAlloc arguments?

xorvax — Sun, 09 Jan 2005 21:16:24 GMT

OK. I thought that there is something another.