You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: permutable_kernel.rs
    path of file: ./repos/linfa/algorithms/linfa-svm/src
    
    the code of the file until where you have to start completion: use crate::Float;
use linfa_kernel::Kernel;
use ndarray::Array1;

pub trait Permutable<F: Float> {
    fn swap_indices(&mut self, i: usize, j: usize);
    fn distances(&self, idx: usize, length: usize) -> Vec<F>;
    fn self_distance(&self, idx: usize) -> F;
    fn inner(&self) -> &Kernel<F>;
    fn into_inner(self) -> Kernel<F>;
}

/// KernelView matrix with permutable columns
///
/// This struct wraps a kernel matrix with access indices. The working set c
    
    fn autotraits() {
        fn has_autotraits<T: Send + Sync + Sized + Unpin>() {}
        has_autotraits::<PermutableKernel<f64>>();
        has_autotraits::<PermutableKernelOneClass<f64>>();
        has_autotraits::<PermutableKernelRegression<f64>>();
    }

    #[test]
    fn test_permutable_kernel() {
        let dist = array![[1.0, 0.3, 0.1], [0.3, 1.0, 0.5], [0.1, 0.5, 1.0]];
        let targets = vec![true, true, true];
        let dist = Kernel {
            inner: KernelInner::Dense(dist),
            method: KernelMethod::Linear,
        };

        let mut kernel = PermutableKernel::new(dist, targets);

        assert_abs_diff_eq!(*kernel.distances(0, 3), [1.0, 0.3, 0.1]);
        assert_abs_diff_eq!(*kernel.distances(1, 3), [0.3, 1.0, 0.5]);
        assert_abs_diff_eq!(*kernel.distances(2, 3), [0.1, 0.5, 1.0]);

        // swap first two nodes
        kernel.swap_indices(0, 1);

        assert_abs_diff_eq!(*kernel.distances(0, 3), [1.0, 0.3, 0.5]);
        assert_abs_diff_eq!(*kernel.distances(1, 3), [0.3, 1.0, 0.1]);
        assert_abs_diff_eq!(*kernel.distances(2, 3), [0.5, 0.1, 1.0]);

        // swap second and third node
        kernel.swap_indices(1, 2);

        assert_abs_diff_eq!(*kernel.distances(0, 3), [1.0, 0.5, 0.3]);
        assert_abs_diff_eq!(*kernel.distances(1, 3), [0.5, 1.0, 0.1]);
        assert_abs_diff_eq!(*kernel.distances(2, 3), [0.3, 0.1, 1.0]);
    }
}