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See the recommended documentation of this function

Ajuda Scilab >> FFTW > fftw_flags

fftw_flags

set computation method of fast fourier transform of the fftw function

Calling Sequence

[a,[S]]=fftw_flags([x1;x2;...])

Arguments

[x1;x2;...]

Matrix of string or integers. Entry to switch the method of fft computation for fftw.

a

Integer. Give the current value of the flag of the fftw function.

S

String matrix. Give the string value of the fftw flag.

Description

This function enables the change of the unsigned flags parameter of the fftw_plan_guru_split_dft function that is used in fftw function.

Default value is FFTW_ESTIMATE

Accepted entries are :

  • FFTW_MEASURE or 0

  • FFTW_DESTROY_INPUT or 1

  • FFTW_UNALIGNED or 2

  • FFTW_CONSERVE_MEMORY or 4

  • FFTW_EXHAUSTIVE or 8

  • FFTW_PRESERVE_INPUT or 16

  • FFTW_PATIENT or 32

  • FFTW_ESTIMATE or 64

  • FFTW_ESTIMATE_PATIENT or 128

  • FFTW_BELIEVE_PCOST or 256

  • FFTW_NO_DFT_R2HC or 512

  • FFTW_NO_NONTHREADED or 1024

  • FFTW_NO_BUFFERING or 2048

  • FFTW_NO_INDIRECT_OP or 4096

  • FFTW_ALLOW_LARGE_GENERIC or 8192

  • FFTW_NO_RANK_SPLITS or 16384

  • FFTW_NO_VRANK_SPLITS or 32768

  • FFTW_NO_VRECURSE or 65536

  • FFTW_NO_SIMD or 131072

  • FFTW_NO_SLOW or 262144

  • FFTW_NO_FIXED_RADIX_LARGE_N or 524288

  • FFTW_ALLOW_PRUNING or 1048576

Rmk : when using FFTW_MEASURE/FFTW_PATIENT/FFTW_EXHAUSTIVE you must call two times fftw. (first call for initialisation, second and others calls for computation)

Examples

//return the integer value of the flag
fftw_flags()

//change flags
fftw_flags(["FFTW_MEASURE";"FFTW_CONSERVE_MEMORY"]);

//change flags and display current value of fftw flags (both integer and strings)
[a,S]=fftw_flags("FFTW_PATIENT")

See Also

  • fftw — Fast fourier transform based on the fftw library
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Last updated:
Thu May 12 11:45:24 CEST 2011