kiss_fftri()

void kiss_fftri	(	kiss_fftr_cfg	st,
		const kiss_fft_cpx *	freqdata,
		kiss_fft_scalar *	timedata )

Definition at line 123 of file kiss_fftr.c.

{
    /* input buffer timedata is stored row-wise */
    int k, ncfft;
 
    if (st->substate->inverse == 0) {
        fprintf (stderr, "kiss fft usage error: improper alloc\n");
        exit (1);
    }
 
    ncfft = st->substate->nfft;
 
    st->tmpbuf[0].r = freqdata[0].r + freqdata[ncfft].r;
    st->tmpbuf[0].i = freqdata[0].r - freqdata[ncfft].r;
    C_FIXDIV(st->tmpbuf[0],2);
 
    for (k = 1; k <= ncfft / 2; ++k) {
        kiss_fft_cpx fk, fnkc, fek, fok, tmp;
        fk = freqdata[k];
        fnkc.r = freqdata[ncfft - k].r;
        fnkc.i = -freqdata[ncfft - k].i;
        C_FIXDIV( fk , 2 );
        C_FIXDIV( fnkc , 2 );
 
        C_ADD (fek, fk, fnkc);
        C_SUB (tmp, fk, fnkc);
        C_MUL (fok, tmp, st->super_twiddles[k-1]);
        C_ADD (st->tmpbuf[k],     fek, fok);
        C_SUB (st->tmpbuf[ncfft - k], fek, fok);
#ifdef USE_SIMD        
        st->tmpbuf[ncfft - k].i *= _mm_set1_ps(-1.0);
#else
        st->tmpbuf[ncfft - k].i *= -1;
#endif
    }
    kiss_fft (st->substate, st->tmpbuf, (kiss_fft_cpx *) timedata);
}

References C_ADD, C_FIXDIV, C_MUL, C_SUB, kiss_fft_cpx::i, kiss_fft_state::inverse, kiss_fft(), kiss_fft_scalar, kiss_fft_state::nfft, kiss_fft_cpx::r, kiss_fftr_state::substate, kiss_fftr_state::super_twiddles, and kiss_fftr_state::tmpbuf.

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