Precision - FFTW 3.2.1

d@0: d@0: d@0: Precision - FFTW 3.2.1 d@0: d@0: d@0: d@0: d@0: d@0: d@0: d@0: d@0: d@0: d@0: d@0: d@0: d@0:

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4.1.2 Precision

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d@0: You can install single and long-double precision versions of FFTW, d@0: which replace double with float and long double, d@0: respectively (see Installation and Customization). To use these d@0: interfaces, you: d@0: d@0:

Link to the single/long-double libraries; on Unix, -lfftw3f or d@0: -lfftw3l instead of (or in addition to) -lfftw3. (You d@0: can link to the different-precision libraries simultaneously.) d@0: d@0:
Include the same <fftw3.h> header file. d@0: d@0:
Replace all lowercase instances of `fftw_' with `fftwf_' or d@0: fftwl_ for single or long-double precision, respectively. d@0: (fftw_complex becomes fftwf_complex, fftw_execute d@0: becomes fftwf_execute, etcetera.) d@0: d@0:
Uppercase names, i.e. names beginning with `FFTW_', remain the d@0: same. d@0: d@0:
Replace double with float or long double for d@0: subroutine parameters. d@0: d@0:

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Depending upon your compiler and/or hardware, long double may not d@0: be any more precise than double (or may not be supported at all, d@0: although it is standard in C99). d@0: d@0: d@0: d@0: d@0: