spectrograms/
sample.rs

1//! Sealed scalar trait abstracting the float precision used by the FFT backend.
2//!
3//! [`Sample`] is implemented for `f32` and `f64` only. It ties a concrete scalar
4//! type to the associated FFT plan types and constructors provided by the active
5//! backend (realfft or fftw), allowing the rest of the crate to be written
6//! generically over precision.
7
8use num_traits::{Float, FloatConst, NumAssign};
9
10use crate::SpectrogramResult;
11use crate::fft_backend::{C2cPlan, C2rPlan, C2rPlan2d, R2cPlan, R2cPlan2d};
12
13mod sealed {
14    pub trait Sealed {}
15    impl Sealed for f32 {}
16    impl Sealed for f64 {}
17}
18
19/// Sealed trait describing a float scalar the FFT backend can operate on.
20///
21/// Implemented for `f32` and `f64`. Each implementor exposes the backend's
22/// concrete plan types and constructors for those plans.
23pub trait Sample:
24    sealed::Sealed
25    + Float
26    + FloatConst
27    + NumAssign
28    + Copy
29    + Send
30    + Sync
31    + 'static
32    + core::fmt::Debug
33    + Default
34{
35    /// Real-to-complex 1D plan type for this scalar.
36    type R2cPlan: R2cPlan<Self>;
37    /// Complex-to-real 1D plan type for this scalar.
38    type C2rPlan: C2rPlan<Self>;
39    /// Complex-to-complex 1D plan type for this scalar.
40    type C2cPlan: C2cPlan<Self>;
41    /// Real-to-complex 2D plan type for this scalar.
42    type R2cPlan2d: R2cPlan2d<Self>;
43    /// Complex-to-real 2D plan type for this scalar.
44    type C2rPlan2d: C2rPlan2d<Self>;
45
46    /// Build a real-to-complex 1D FFT plan of length `n_fft`.
47    ///
48    /// # Errors
49    ///
50    /// Returns an error if the backend fails to construct the plan.
51    fn plan_r2c(n_fft: usize) -> SpectrogramResult<Self::R2cPlan>;
52
53    /// Build a complex-to-real 1D inverse FFT plan of length `n_fft`.
54    ///
55    /// # Errors
56    ///
57    /// Returns an error if the backend fails to construct the plan.
58    fn plan_c2r(n_fft: usize) -> SpectrogramResult<Self::C2rPlan>;
59
60    /// Build a complex-to-complex 1D FFT plan of length `n_fft`.
61    ///
62    /// # Errors
63    ///
64    /// Returns an error if the backend fails to construct the plan.
65    fn plan_c2c(n_fft: usize) -> SpectrogramResult<Self::C2cPlan>;
66
67    /// Build a real-to-complex 2D FFT plan of dimensions `nrows` x `ncols`.
68    ///
69    /// # Errors
70    ///
71    /// Returns an error if the backend fails to construct the plan.
72    fn plan_r2c_2d(nrows: usize, ncols: usize) -> SpectrogramResult<Self::R2cPlan2d>;
73
74    /// Build a complex-to-real 2D inverse FFT plan of dimensions `nrows` x `ncols`.
75    ///
76    /// # Errors
77    ///
78    /// Returns an error if the backend fails to construct the plan.
79    fn plan_c2r_2d(nrows: usize, ncols: usize) -> SpectrogramResult<Self::C2rPlan2d>;
80
81    /// Convert an `f64` constant/literal to this scalar (for PI-derived consts, casts).
82    fn from_f64(x: f64) -> Self;
83
84    /// Convert a `usize` (e.g. an index or length) to this scalar.
85    fn from_usize(n: usize) -> Self;
86}
spectrograms/sample.rs

spectrograms/
sample.rs
