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</pre><pre class="rust"><code><span class="attr">#[cfg(feature = <span class="string">"serde-serialize-no-std"</span>)]
</span><span class="kw">use </span>serde::{Deserialize, Serialize};
<span class="kw">use </span>num::One;
<span class="kw">use </span>simba::scalar::ClosedNeg;
<span class="kw">use </span><span class="kw">crate</span>::allocator::Allocator;
<span class="kw">use </span><span class="kw">crate</span>::base::{DefaultAllocator, Matrix, OVector, Scalar};
<span class="attr">#[cfg(any(feature = <span class="string">"std"</span>, feature = <span class="string">"alloc"</span>))]
</span><span class="kw">use </span><span class="kw">crate</span>::dimension::Dyn;
<span class="kw">use </span><span class="kw">crate</span>::dimension::{Const, Dim, DimName};
<span class="kw">use </span><span class="kw">crate</span>::storage::StorageMut;
<span class="doccomment">/// A sequence of row or column permutations.
</span><span class="attr">#[cfg_attr(feature = <span class="string">"serde-serialize-no-std"</span>, derive(Serialize, Deserialize))]
#[cfg_attr(
feature = <span class="string">"serde-serialize-no-std"</span>,
serde(bound(serialize = <span class="string">"DefaultAllocator: Allocator<(usize, usize), D>,
OVector<(usize, usize), D>: Serialize"</span>))
)]
#[cfg_attr(
feature = <span class="string">"serde-serialize-no-std"</span>,
serde(bound(deserialize = <span class="string">"DefaultAllocator: Allocator<(usize, usize), D>,
OVector<(usize, usize), D>: Deserialize<'de>"</span>))
)]
#[derive(Clone, Debug)]
</span><span class="kw">pub struct </span>PermutationSequence<D: Dim>
<span class="kw">where
</span>DefaultAllocator: Allocator<(usize, usize), D>,
{
len: usize,
ipiv: OVector<(usize, usize), D>,
}
<span class="kw">impl</span><D: Dim> Copy <span class="kw">for </span>PermutationSequence<D>
<span class="kw">where
</span>DefaultAllocator: Allocator<(usize, usize), D>,
OVector<(usize, usize), D>: Copy,
{
}
<span class="kw">impl</span><D: DimName> PermutationSequence<D>
<span class="kw">where
</span>DefaultAllocator: Allocator<(usize, usize), D>,
{
<span class="doccomment">/// Creates a new statically-allocated sequence of `D` identity permutations.
</span><span class="attr">#[inline]
</span><span class="kw">pub fn </span>identity() -> <span class="self">Self </span>{
<span class="self">Self</span>::identity_generic(D::name())
}
}
<span class="attr">#[cfg(any(feature = <span class="string">"std"</span>, feature = <span class="string">"alloc"</span>))]
</span><span class="kw">impl </span>PermutationSequence<Dyn>
<span class="kw">where
</span>DefaultAllocator: Allocator<(usize, usize), Dyn>,
{
<span class="doccomment">/// Creates a new dynamically-allocated sequence of `n` identity permutations.
</span><span class="attr">#[inline]
</span><span class="kw">pub fn </span>identity(n: usize) -> <span class="self">Self </span>{
<span class="self">Self</span>::identity_generic(Dyn(n))
}
}
<span class="kw">impl</span><D: Dim> PermutationSequence<D>
<span class="kw">where
</span>DefaultAllocator: Allocator<(usize, usize), D>,
{
<span class="doccomment">/// Creates a new sequence of D identity permutations.
</span><span class="attr">#[inline]
</span><span class="kw">pub fn </span>identity_generic(dim: D) -> <span class="self">Self </span>{
<span class="self">Self </span>{
len: <span class="number">0</span>,
<span class="comment">// TODO: using a uninitialized matrix would save some computation, but
// that loos difficult to setup with MaybeUninit.
</span>ipiv: Matrix::repeat_generic(dim, Const::<<span class="number">1</span>>, (<span class="number">0</span>, <span class="number">0</span>)),
}
}
<span class="doccomment">/// Adds the interchange of the row (or column) `i` with the row (or column) `i2` to this
/// sequence of permutations.
</span><span class="attr">#[inline]
</span><span class="kw">pub fn </span>append_permutation(<span class="kw-2">&mut </span><span class="self">self</span>, i: usize, i2: usize) {
<span class="kw">if </span>i != i2 {
<span class="macro">assert!</span>(
<span class="self">self</span>.len < <span class="self">self</span>.ipiv.len(),
<span class="string">"Maximum number of permutations exceeded."
</span>);
<span class="self">self</span>.ipiv[<span class="self">self</span>.len] = (i, i2);
<span class="self">self</span>.len += <span class="number">1</span>;
}
}
<span class="doccomment">/// Applies this sequence of permutations to the rows of `rhs`.
</span><span class="attr">#[inline]
</span><span class="kw">pub fn </span>permute_rows<T: Scalar, R2: Dim, C2: Dim, S2>(<span class="kw-2">&</span><span class="self">self</span>, rhs: <span class="kw-2">&mut </span>Matrix<T, R2, C2, S2>)
<span class="kw">where
</span>S2: StorageMut<T, R2, C2>,
{
<span class="kw">for </span>i <span class="kw">in </span><span class="self">self</span>.ipiv.rows_range(..<span class="self">self</span>.len).iter() {
rhs.swap_rows(i.<span class="number">0</span>, i.<span class="number">1</span>)
}
}
<span class="doccomment">/// Applies this sequence of permutations in reverse to the rows of `rhs`.
</span><span class="attr">#[inline]
</span><span class="kw">pub fn </span>inv_permute_rows<T: Scalar, R2: Dim, C2: Dim, S2>(<span class="kw-2">&</span><span class="self">self</span>, rhs: <span class="kw-2">&mut </span>Matrix<T, R2, C2, S2>)
<span class="kw">where
</span>S2: StorageMut<T, R2, C2>,
{
<span class="kw">for </span>i <span class="kw">in </span><span class="number">0</span>..<span class="self">self</span>.len {
<span class="kw">let </span>(i1, i2) = <span class="self">self</span>.ipiv[<span class="self">self</span>.len - i - <span class="number">1</span>];
rhs.swap_rows(i1, i2)
}
}
<span class="doccomment">/// Applies this sequence of permutations to the columns of `rhs`.
</span><span class="attr">#[inline]
</span><span class="kw">pub fn </span>permute_columns<T: Scalar, R2: Dim, C2: Dim, S2>(<span class="kw-2">&</span><span class="self">self</span>, rhs: <span class="kw-2">&mut </span>Matrix<T, R2, C2, S2>)
<span class="kw">where
</span>S2: StorageMut<T, R2, C2>,
{
<span class="kw">for </span>i <span class="kw">in </span><span class="self">self</span>.ipiv.rows_range(..<span class="self">self</span>.len).iter() {
rhs.swap_columns(i.<span class="number">0</span>, i.<span class="number">1</span>)
}
}
<span class="doccomment">/// Applies this sequence of permutations in reverse to the columns of `rhs`.
</span><span class="attr">#[inline]
</span><span class="kw">pub fn </span>inv_permute_columns<T: Scalar, R2: Dim, C2: Dim, S2>(
<span class="kw-2">&</span><span class="self">self</span>,
rhs: <span class="kw-2">&mut </span>Matrix<T, R2, C2, S2>,
) <span class="kw">where
</span>S2: StorageMut<T, R2, C2>,
{
<span class="kw">for </span>i <span class="kw">in </span><span class="number">0</span>..<span class="self">self</span>.len {
<span class="kw">let </span>(i1, i2) = <span class="self">self</span>.ipiv[<span class="self">self</span>.len - i - <span class="number">1</span>];
rhs.swap_columns(i1, i2)
}
}
<span class="doccomment">/// The number of non-identity permutations applied by this sequence.
</span><span class="attr">#[must_use]
</span><span class="kw">pub fn </span>len(<span class="kw-2">&</span><span class="self">self</span>) -> usize {
<span class="self">self</span>.len
}
<span class="doccomment">/// Returns true if the permutation sequence contains no elements.
</span><span class="attr">#[must_use]
</span><span class="kw">pub fn </span>is_empty(<span class="kw-2">&</span><span class="self">self</span>) -> bool {
<span class="self">self</span>.len() == <span class="number">0
</span>}
<span class="doccomment">/// The determinant of the matrix corresponding to this permutation.
</span><span class="attr">#[inline]
#[must_use]
</span><span class="kw">pub fn </span>determinant<T: One + ClosedNeg>(<span class="kw-2">&</span><span class="self">self</span>) -> T {
<span class="kw">if </span><span class="self">self</span>.len % <span class="number">2 </span>== <span class="number">0 </span>{
T::one()
} <span class="kw">else </span>{
-T::one()
}
}
}
</code></pre></div>
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