rufft 0.1.0

A pure rust FFT library !
Documentation 
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//! Signal processing functions which operate on `Iterable` implemenentors. Named 
//! `itertools` after the `itertool` crate

pub mod complex;
use num_traits::{ Float, FloatConst, NumAssign };
use crate::traits::Iterable;

/// Clone and pad the real valued input collection with the floating 
/// point type `F` to the length `len`
pub fn pad<F, I>(x: &I, padding: F, len: usize) -> Result<I, ()> 
where
    F: Float + FloatConst + NumAssign + 'static,
    for<'c> I: Iterable<OwnedItem = F, Item<'c> = &'c F>,
{
    let n = x.iter().len();
    if len < n {
        return Err(());
    }
    let num_padding = len - n;
    let pad_iter = core::iter::repeat(padding).take(num_padding);
    Ok(I::from_iter(x.iter().cloned().chain(pad_iter)))
}

/// Clone and zero pad the real valued input collection to the length `len`
pub fn zero_pad<F, I>(n: usize, x: &I) -> Result<I, ()> 
where
    F: Float + FloatConst + NumAssign + 'static,
    for<'c> I: Iterable<OwnedItem = F, Item<'c> = &'c F>,
{
    Ok(pad(x, F::zero(), n)?)
}

/// Clone and pad the real valued input collection with floating point value `F`
/// to the nearest power of two length
pub fn pad_to_nearest_power_of_two<F, I>(x: &I, padding: F) -> Result<I, ()>
where
    F: Float + FloatConst + NumAssign + 'static,
    for<'c> I: Iterable<OwnedItem = F, Item<'c> = &'c F>,
    I: Clone
{
    let n = x.iter().len();
    if n.is_power_of_two() {
        Ok(x.clone())
    } else {
        Ok(pad(x, padding, n.next_power_of_two())?) // Pad to the nearest power of 2
    }
}

/// Clone and zero pad the real valued input collection to the nearest power 
/// of two length
pub fn zero_pad_to_nearest_power_of_two<F, I>(x: &I) -> Result<I, ()>
where
    F: Float + FloatConst + NumAssign + 'static,
    for<'c> I: Iterable<OwnedItem = F, Item<'c> = &'c F>,
    I: Clone
{
    pad_to_nearest_power_of_two(x, F::zero())
}