nalgebra/src/sparse/cs_matrix.rs
2019-03-23 14:33:47 +01:00

518 lines
15 KiB
Rust

use alga::general::ClosedAdd;
use num::Zero;
use std::iter;
use std::marker::PhantomData;
use std::ops::Range;
use std::slice;
use crate::allocator::Allocator;
use crate::sparse::cs_utils;
use crate::{
DefaultAllocator, Dim, Dynamic, Scalar, Vector, VectorN, U1
};
pub struct ColumnEntries<'a, N> {
curr: usize,
i: &'a [usize],
v: &'a [N],
}
impl<'a, N> ColumnEntries<'a, N> {
#[inline]
pub fn new(i: &'a [usize], v: &'a [N]) -> Self {
assert_eq!(i.len(), v.len());
Self { curr: 0, i, v }
}
}
impl<'a, N: Copy> Iterator for ColumnEntries<'a, N> {
type Item = (usize, N);
#[inline]
fn next(&mut self) -> Option<Self::Item> {
if self.curr >= self.i.len() {
None
} else {
let res = Some((unsafe { *self.i.get_unchecked(self.curr) }, unsafe {
*self.v.get_unchecked(self.curr)
}));
self.curr += 1;
res
}
}
}
// FIXME: this structure exists for now only because impl trait
// cannot be used for trait method return types.
/// Trait for iterable compressed-column matrix storage.
pub trait CsStorageIter<'a, N, R, C = U1> {
/// Iterator through all the rows of a specific columns.
///
/// The elements are given as a tuple (row_index, value).
type ColumnEntries: Iterator<Item = (usize, N)>;
/// Iterator through the row indices of a specific column.
type ColumnRowIndices: Iterator<Item = usize>;
/// Iterates through all the row indices of the j-th column.
fn column_row_indices(&'a self, j: usize) -> Self::ColumnRowIndices;
#[inline(always)]
/// Iterates through all the entries of the j-th column.
fn column_entries(&'a self, j: usize) -> Self::ColumnEntries;
}
/// Trait for mutably iterable compressed-column sparse matrix storage.
pub trait CsStorageIterMut<'a, N: 'a, R, C = U1> {
/// Mutable iterator through all the values of the sparse matrix.
type ValuesMut: Iterator<Item = &'a mut N>;
/// Mutable iterator through all the rows of a specific columns.
///
/// The elements are given as a tuple (row_index, value).
type ColumnEntriesMut: Iterator<Item = (usize, &'a mut N)>;
/// A mutable iterator through the values buffer of the sparse matrix.
fn values_mut(&'a mut self) -> Self::ValuesMut;
/// Iterates mutably through all the entries of the j-th column.
fn column_entries_mut(&'a mut self, j: usize) -> Self::ColumnEntriesMut;
}
/// Trait for compressed column sparse matrix storage.
pub trait CsStorage<N, R, C = U1>: for<'a> CsStorageIter<'a, N, R, C> {
/// The shape of the stored matrix.
fn shape(&self) -> (R, C);
/// Retrieve the i-th row index of the underlying row index buffer.
///
/// No bound-checking is performed.
unsafe fn row_index_unchecked(&self, i: usize) -> usize;
/// The i-th value on the contiguous value buffer of this storage.
///
/// No bound-checking is performed.
unsafe fn get_value_unchecked(&self, i: usize) -> &N;
/// The i-th value on the contiguous value buffer of this storage.
fn get_value(&self, i: usize) -> &N;
/// Retrieve the i-th row index of the underlying row index buffer.
fn row_index(&self, i: usize) -> usize;
/// The value indices for the `i`-th column.
fn column_range(&self, i: usize) -> Range<usize>;
/// The size of the value buffer (i.e. the entries known as possibly being non-zero).
fn len(&self) -> usize;
}
/// Trait for compressed column sparse matrix mutable storage.
pub trait CsStorageMut<N, R, C = U1>:
CsStorage<N, R, C> + for<'a> CsStorageIterMut<'a, N, R, C>
{
}
/// A storage of column-compressed sparse matrix based on a Vec.
#[derive(Clone, Debug, PartialEq)]
pub struct CsVecStorage<N: Scalar, R: Dim, C: Dim>
where DefaultAllocator: Allocator<usize, C>
{
pub(crate) shape: (R, C),
pub(crate) p: VectorN<usize, C>,
pub(crate) i: Vec<usize>,
pub(crate) vals: Vec<N>,
}
impl<N: Scalar, R: Dim, C: Dim> CsVecStorage<N, R, C>
where DefaultAllocator: Allocator<usize, C>
{
/// The value buffer of this storage.
pub fn values(&self) -> &[N] {
&self.vals
}
/// The column shifts buffer.
pub fn p(&self) -> &[usize] {
self.p.as_slice()
}
/// The row index buffers.
pub fn i(&self) -> &[usize] {
&self.i
}
}
impl<N: Scalar, R: Dim, C: Dim> CsVecStorage<N, R, C> where DefaultAllocator: Allocator<usize, C> {}
impl<'a, N: Scalar, R: Dim, C: Dim> CsStorageIter<'a, N, R, C> for CsVecStorage<N, R, C>
where DefaultAllocator: Allocator<usize, C>
{
type ColumnEntries = ColumnEntries<'a, N>;
type ColumnRowIndices = iter::Cloned<slice::Iter<'a, usize>>;
#[inline]
fn column_entries(&'a self, j: usize) -> Self::ColumnEntries {
let rng = self.column_range(j);
ColumnEntries::new(&self.i[rng.clone()], &self.vals[rng])
}
#[inline]
fn column_row_indices(&'a self, j: usize) -> Self::ColumnRowIndices {
let rng = self.column_range(j);
self.i[rng.clone()].iter().cloned()
}
}
impl<N: Scalar, R: Dim, C: Dim> CsStorage<N, R, C> for CsVecStorage<N, R, C>
where DefaultAllocator: Allocator<usize, C>
{
#[inline]
fn shape(&self) -> (R, C) {
self.shape
}
#[inline]
fn len(&self) -> usize {
self.vals.len()
}
#[inline]
fn row_index(&self, i: usize) -> usize {
self.i[i]
}
#[inline]
unsafe fn row_index_unchecked(&self, i: usize) -> usize {
*self.i.get_unchecked(i)
}
#[inline]
unsafe fn get_value_unchecked(&self, i: usize) -> &N {
self.vals.get_unchecked(i)
}
#[inline]
fn get_value(&self, i: usize) -> &N {
&self.vals[i]
}
#[inline]
fn column_range(&self, j: usize) -> Range<usize> {
let end = if j + 1 == self.p.len() {
self.len()
} else {
self.p[j + 1]
};
self.p[j]..end
}
}
impl<'a, N: Scalar, R: Dim, C: Dim> CsStorageIterMut<'a, N, R, C> for CsVecStorage<N, R, C>
where DefaultAllocator: Allocator<usize, C>
{
type ValuesMut = slice::IterMut<'a, N>;
type ColumnEntriesMut = iter::Zip<iter::Cloned<slice::Iter<'a, usize>>, slice::IterMut<'a, N>>;
#[inline]
fn values_mut(&'a mut self) -> Self::ValuesMut {
self.vals.iter_mut()
}
#[inline]
fn column_entries_mut(&'a mut self, j: usize) -> Self::ColumnEntriesMut {
let rng = self.column_range(j);
self.i[rng.clone()]
.iter()
.cloned()
.zip(self.vals[rng].iter_mut())
}
}
impl<N: Scalar, R: Dim, C: Dim> CsStorageMut<N, R, C> for CsVecStorage<N, R, C> where DefaultAllocator: Allocator<usize, C>
{}
/*
pub struct CsSliceStorage<'a, N: Scalar, R: Dim, C: DimAdd<U1>> {
shape: (R, C),
p: VectorSlice<usize, DimSum<C, U1>>,
i: VectorSlice<usize, Dynamic>,
vals: VectorSlice<N, Dynamic>,
}*/
/// A compressed sparse column matrix.
#[derive(Clone, Debug, PartialEq)]
pub struct CsMatrix<
N: Scalar,
R: Dim = Dynamic,
C: Dim = Dynamic,
S: CsStorage<N, R, C> = CsVecStorage<N, R, C>,
> {
pub(crate) data: S,
_phantoms: PhantomData<(N, R, C)>,
}
/// A column compressed sparse vector.
pub type CsVector<N, R = Dynamic, S = CsVecStorage<N, R, U1>> = CsMatrix<N, R, U1, S>;
impl<N: Scalar, R: Dim, C: Dim> CsMatrix<N, R, C>
where DefaultAllocator: Allocator<usize, C>
{
/// Creates a new compressed sparse column matrix with the specified dimension and
/// `nvals` possible non-zero values.
pub fn new_uninitialized_generic(nrows: R, ncols: C, nvals: usize) -> Self {
let mut i = Vec::with_capacity(nvals);
unsafe {
i.set_len(nvals);
}
i.shrink_to_fit();
let mut vals = Vec::with_capacity(nvals);
unsafe {
vals.set_len(nvals);
}
vals.shrink_to_fit();
CsMatrix {
data: CsVecStorage {
shape: (nrows, ncols),
p: VectorN::zeros_generic(ncols, U1),
i,
vals,
},
_phantoms: PhantomData,
}
}
/*
pub(crate) fn from_parts_generic(
nrows: R,
ncols: C,
p: VectorN<usize, C>,
i: Vec<usize>,
vals: Vec<N>,
) -> Self
where
N: Zero + ClosedAdd,
DefaultAllocator: Allocator<N, R>,
{
assert_eq!(ncols.value(), p.len(), "Invalid inptr size.");
assert_eq!(i.len(), vals.len(), "Invalid value size.");
// Check p.
for ptr in &p {
assert!(*ptr < i.len(), "Invalid inptr value.");
}
for ptr in p.as_slice().windows(2) {
assert!(ptr[0] <= ptr[1], "Invalid inptr ordering.");
}
// Check i.
for i in &i {
assert!(*i < nrows.value(), "Invalid row ptr value.")
}
let mut res = CsMatrix {
data: CsVecStorage {
shape: (nrows, ncols),
p,
i,
vals,
},
_phantoms: PhantomData,
};
// Sort and remove duplicates.
res.sort();
res.dedup();
res
}*/
}
/*
impl<N: Scalar + Zero + ClosedAdd> CsMatrix<N> {
pub(crate) fn from_parts(
nrows: usize,
ncols: usize,
p: Vec<usize>,
i: Vec<usize>,
vals: Vec<N>,
) -> Self
{
let nrows = Dynamic::new(nrows);
let ncols = Dynamic::new(ncols);
let p = DVector::from_data(VecStorage::new(ncols, U1, p));
Self::from_parts_generic(nrows, ncols, p, i, vals)
}
}
*/
impl<N: Scalar, R: Dim, C: Dim, S: CsStorage<N, R, C>> CsMatrix<N, R, C, S> {
pub(crate) fn from_data(data: S) -> Self {
CsMatrix {
data,
_phantoms: PhantomData,
}
}
/// The size of the data buffer.
pub fn len(&self) -> usize {
self.data.len()
}
/// The number of rows of this matrix.
pub fn nrows(&self) -> usize {
self.data.shape().0.value()
}
/// The number of rows of this matrix.
pub fn ncols(&self) -> usize {
self.data.shape().1.value()
}
/// The shape of this matrix.
pub fn shape(&self) -> (usize, usize) {
let (nrows, ncols) = self.data.shape();
(nrows.value(), ncols.value())
}
/// Whether this matrix is square or not.
pub fn is_square(&self) -> bool {
let (nrows, ncols) = self.data.shape();
nrows.value() == ncols.value()
}
/// Should always return `true`.
///
/// This method is generally used for debugging and should typically not be called in user code.
/// This checks that the row inner indices of this matrix are sorted. It takes `O(n)` time,
/// where n` is `self.len()`.
/// All operations of CSC matrices on nalgebra assume, and will return, sorted indices.
/// If at any time this `is_sorted` method returns `false`, then, something went wrong
/// and an issue should be open on the nalgebra repository with details on how to reproduce
/// this.
pub fn is_sorted(&self) -> bool {
for j in 0..self.ncols() {
let mut curr = None;
for idx in self.data.column_row_indices(j) {
if let Some(curr) = curr {
if idx <= curr {
return false;
}
}
curr = Some(idx);
}
}
true
}
/// Computes the transpose of this sparse matrix.
pub fn transpose(&self) -> CsMatrix<N, C, R>
where DefaultAllocator: Allocator<usize, R> {
let (nrows, ncols) = self.data.shape();
let nvals = self.len();
let mut res = CsMatrix::new_uninitialized_generic(ncols, nrows, nvals);
let mut workspace = Vector::zeros_generic(nrows, U1);
// Compute p.
for i in 0..nvals {
let row_id = self.data.row_index(i);
workspace[row_id] += 1;
}
let _ = cs_utils::cumsum(&mut workspace, &mut res.data.p);
// Fill the result.
for j in 0..ncols.value() {
for (row_id, value) in self.data.column_entries(j) {
let shift = workspace[row_id];
res.data.vals[shift] = value;
res.data.i[shift] = j;
workspace[row_id] += 1;
}
}
res
}
}
impl<N: Scalar, R: Dim, C: Dim, S: CsStorageMut<N, R, C>> CsMatrix<N, R, C, S> {
/// Iterator through all the mutable values of this sparse matrix.
#[inline]
pub fn values_mut(&mut self) -> impl Iterator<Item = &mut N> {
self.data.values_mut()
}
}
impl<N: Scalar, R: Dim, C: Dim> CsMatrix<N, R, C>
where DefaultAllocator: Allocator<usize, C>
{
pub(crate) fn sort(&mut self)
where DefaultAllocator: Allocator<N, R> {
// Size = R
let nrows = self.data.shape().0;
let mut workspace = unsafe { VectorN::new_uninitialized_generic(nrows, U1) };
self.sort_with_workspace(workspace.as_mut_slice());
}
pub(crate) fn sort_with_workspace(&mut self, workspace: &mut [N]) {
assert!(
workspace.len() >= self.nrows(),
"Workspace must be able to hold at least self.nrows() elements."
);
for j in 0..self.ncols() {
// Scatter the row in the workspace.
for (irow, val) in self.data.column_entries(j) {
workspace[irow] = val;
}
// Sort the index vector.
let range = self.data.column_range(j);
self.data.i[range.clone()].sort();
// Permute the values too.
for (i, irow) in range.clone().zip(self.data.i[range].iter().cloned()) {
self.data.vals[i] = workspace[irow];
}
}
}
// Remove dupliate entries on a sorted CsMatrix.
pub(crate) fn dedup(&mut self)
where N: Zero + ClosedAdd {
let mut curr_i = 0;
for j in 0..self.ncols() {
let range = self.data.column_range(j);
self.data.p[j] = curr_i;
if range.start != range.end {
let mut value = N::zero();
let mut irow = self.data.i[range.start];
for idx in range {
let curr_irow = self.data.i[idx];
if curr_irow == irow {
value += self.data.vals[idx];
} else {
self.data.i[curr_i] = irow;
self.data.vals[curr_i] = value;
value = self.data.vals[idx];
irow = curr_irow;
curr_i += 1;
}
}
// Handle the last entry.
self.data.i[curr_i] = irow;
self.data.vals[curr_i] = value;
curr_i += 1;
}
}
self.data.i.truncate(curr_i);
self.data.i.shrink_to_fit();
self.data.vals.truncate(curr_i);
self.data.vals.shrink_to_fit();
}
}