1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41

use crate::kernel::Kernel;
use crate::math::Real;
use na::RealField;

/// The Spiky smoothing kernel.
///
/// Refer to "Particle-Based Fluid Simulation for Interactive Applications", Müller et al.pub struct SpikyKernel;
#[derive(Copy, Clone, Debug)]
pub struct SpikyKernel;

impl Kernel for SpikyKernel {
    fn scalar_apply(r: Real, h: Real) -> Real {
        assert!(r >= na::zero::<Real>());

        #[cfg(feature = "dim2")]
        let normalizer = na::convert::<_, Real>(10.0) / (Real::pi() * h.powi(5));
        #[cfg(feature = "dim3")]
        let normalizer = na::convert::<_, Real>(15.0) / (Real::pi() * h.powi(6));

        if r <= h {
            normalizer * (h - r).powi(3)
        } else {
            na::zero::<Real>()
        }
    }

    fn scalar_apply_diff(r: Real, h: Real) -> Real {
        assert!(r >= na::zero::<Real>());

        #[cfg(feature = "dim2")]
        let normalizer = na::convert::<_, Real>(10.0) / (Real::pi() * h.powi(5));
        #[cfg(feature = "dim3")]
        let normalizer = na::convert::<_, Real>(15.0) / (Real::pi() * h.powi(6));

        if r <= h {
            -normalizer * (h - r).powi(2) * na::convert::<_, Real>(3.0)
        } else {
            na::zero::<Real>()
        }
    }
}