mop-structs 0.0.10

//! CSR (Compressed Sparse Row) matrix.
//!
//! See [Wikipedia](https://en.wikipedia.org/wiki/Sparse_matrix).

#[cfg(feature = "rand")]
mod csr_matrix_rnd;
mod csr_matrix_row_constructor;
mod csr_matrix_row_iter_impls;
#[cfg(feature = "rayon")]
mod csr_matrix_row_par_iter_impls;

pub use self::{
  csr_matrix_row_constructor::CsrMatrixRowConstructor,
  csr_matrix_row_iter_impls::{CsrMatrixRowIter, CsrMatrixRowIterMut},
};
use crate::{
  dim::Dim,
  prelude::{Array, DynDenseStoMut, DynDenseStoRef, Matrix, StDenseStoMut, StDenseStoRef},
  utils::{are_in_upper_bound, does_not_have_duplicates},
  vec::{
    css::{CssSlice, CssSliceMut},
    VecArray,
  },
};
use core::ops::Range;

/// This structure can hold differents mixed types of indexed storages.
#[cfg_attr(
  feature = "serde1",
  derive(mop_common_deps::serde::Deserialize, mop_common_deps::serde::Serialize)
)]
#[derive(Clone, Copy, Debug, Default, Hash, PartialEq, PartialOrd)]
pub struct CsrMatrix<DS, US> {
  data: DS,
  dim: Dim<[usize; 2]>,
  indcs: US,
  ptrs: US,
}

pub type CsrMatrixArray<DA, UA> = CsrMatrix<DA, UA>;
#[cfg(feature = "std")]
pub type CsrMatrixVec<T> = CsrMatrix<Vec<T>, Vec<usize>>;
pub type CsrMatrixVecArray<DA, UA> = CsrMatrix<VecArray<DA>, VecArray<UA>>;
pub type CsrMatrixRef<'a, T> = CsrMatrix<&'a [T], &'a [usize]>;

#[cfg(feature = "std")]
impl<T> CsrMatrixVec<T> {
  #[cfg(feature = "rand")]
  pub fn new_rnd<F, R>(shape: [usize; 2], nnz: usize, rng: &mut R, cb: F) -> Self
  where
    F: FnMut(&mut R, [usize; 2]) -> T,
    R: mop_common_deps::rand::Rng,
  {
    let dim: Dim<[usize; 2]> = shape.into();
    let capacity = dim.rows() * dim.cols();
    assert!(nnz <= capacity);
    let mut cmr = self::csr_matrix_rnd::CsrMatrixRnd {
      data: Vec::with_capacity(nnz),
      dim: &dim,
      indcs: Vec::with_capacity(nnz),
      nnz,
      ptrs: Vec::with_capacity(dim.rows() + 1),
      rng,
    };
    cmr.fill_ptrs();
    cmr.fill_indcs();
    cmr.fill_data(cb);
    CsrMatrixVec::new([dim.rows(), dim.cols()], cmr.data, cmr.indcs, cmr.ptrs)
  }

  pub fn with_vec_capacity(shape: [usize; 2], nnz: usize) -> Self {
    let mut ptrs = Vec::with_capacity(shape[0] + 1);
    ptrs.push(0);
    CsrMatrix {
      data: Vec::with_capacity(nnz),
      dim: [0, shape[1]].into(),
      indcs: Vec::with_capacity(nnz),
      ptrs,
    }
  }
}

impl<DA, UA> CsrMatrixVecArray<DA, UA>
where
  DA: Array,
  UA: Array<Item = usize>,
{
  #[cfg(feature = "rand")]
  pub fn new_rnd<F, R>(shape: [usize; 2], nnz: usize, rng: &mut R, cb: F) -> Self
  where
    F: FnMut(&mut R, [usize; 2]) -> DA::Item,
    R: mop_common_deps::rand::Rng,
  {
    let dim: Dim<[usize; 2]> = shape.into();
    let capacity = dim.rows() * dim.cols();
    assert!(nnz <= capacity);
    let mut cmr = self::csr_matrix_rnd::CsrMatrixRnd {
      data: VecArray::<DA>::with_capacity(),
      dim: &dim,
      indcs: VecArray::<UA>::with_capacity(),
      nnz,
      ptrs: VecArray::<UA>::with_capacity(),
      rng,
    };
    cmr.fill_ptrs();
    cmr.fill_indcs();
    cmr.fill_data(cb);
    CsrMatrixVecArray::new([dim.rows(), dim.cols()], cmr.data, cmr.indcs, cmr.ptrs)
  }

  pub fn with_vec_array(cols: usize) -> Self {
    let mut ptrs_vec_array = VecArray::with_capacity();
    ptrs_vec_array.push(0);
    CsrMatrixVecArray {
      data: VecArray::with_capacity(),
      dim: [0, cols].into(),
      indcs: VecArray::with_capacity(),
      ptrs: ptrs_vec_array,
    }
  }
}

impl<DS, US> CsrMatrix<DS, US>
where
  DS: StDenseStoRef,
  US: StDenseStoRef<Item = usize>,
{
  /// Creates a new [`CsrMatrix`](CsrMatrix) from raw parameters.
  ///
  /// # Arguments
  ///
  /// * `shape` - An array containing the number of rows and columns.
  /// * `data` - The matrix data.
  /// * `indcs` - Each column index of its corresponding data.
  /// * `ptrs` - The length of each row.
  ///
  /// # Examples
  ///
  /// ```rust
  /// use mop_structs::matrix::csr_matrix::CsrMatrixArray;
  /// let _ = CsrMatrixArray::new([2, 4], [1, 2, 3], [0, 1, 2], [0, 3, 3]);
  /// ```
  ///
  /// # Assertions
  ///
  /// * The length of `data` must be equal the length of `indcs`.
  ///
  /// ```should_panic
  /// use mop_structs::matrix::csr_matrix::CsrMatrixRef;
  /// let _ = CsrMatrixRef::new([2, 4], &[1, 2, 3], &[], &[0, 3, 3]);
  /// ```
  ///
  /// * The length of `data` is greater than the number of rows times the number of columns.
  ///
  /// ```should_panic
  /// use mop_structs::matrix::csr_matrix::CsrMatrixRef;
  /// let _ = CsrMatrixRef::new(
  ///     [2, 4], &[1, 2, 3, 4, 5, 6, 7, 8, 9], &[0, 1, 2, 3, 0, 1, 2, 3, 0], &[0, 4, 8]
  /// );
  /// ```
  ///
  /// * The length of `ptrs` must be equal the number of rows plus 1.
  ///
  /// ```should_panic
  /// use mop_structs::matrix::csr_matrix::CsrMatrixRef;
  /// let _ = CsrMatrixRef::new([2, 4], &[1, 2, 3], &[0, 1, 2], &[0, 3, 3, 3, 3]);
  /// ```
  ///
  /// * Column indices must be less than the number of columns.
  ///
  /// ```should_panic
  /// use mop_structs::matrix::csr_matrix::CsrMatrixRef;
  /// let _ = CsrMatrixRef::new([2, 4], &[1, 2, 3], &[0, 1, 9], &[0, 3, 3]);
  /// ```
  ///
  /// * Column indices of a row must be unique.
  ///
  /// ```should_panic
  /// use mop_structs::matrix::csr_matrix::CsrMatrixRef;
  /// let _ = CsrMatrixRef::new([2, 4], &[1, 2, 3], &[0, 0, 0], &[0, 3, 3]);
  /// ```
  ///
  /// * Rows length must end with the nnz.
  ///
  /// ```should_panic
  /// use mop_structs::matrix::csr_matrix::CsrMatrixRef;
  /// let _ = CsrMatrixRef::new([2, 4], &[1, 2, 3], &[0, 1, 2], &[0, 3, 9]);
  /// ```
  ///
  /// * Rows length must be in ascending order.
  ///
  /// ```should_panic
  ///  use mop_structs::matrix::csr_matrix::CsrMatrixRef;
  ///  let _ = CsrMatrixRef::new([3, 4], &[1, 2, 3, 4], &[0, 0, 0, 1], &[0, 1, 0, 4]);
  /// ```
  pub fn new(shape: [usize; 2], data: DS, indcs: US, ptrs: US) -> Self {
    let dim: Dim<[usize; 2]> = shape.into();
    assert!(
      data.as_slice().len() == indcs.as_slice().len(),
      "The length of `data` must be equal the length of `indcs`."
    );
    assert!(
      data.as_slice().len() <= dim.rows() * dim.cols(),
      "The length of `data` must be less than the number of rows times the \
       number of columns."
    );
    assert!(
      ptrs.as_slice().len() == dim.rows() + 1,
      "The length of `ptrs` must be equal the number of rows plus 1."
    );
    assert!(
      are_in_upper_bound(indcs.as_slice(), &dim.cols()),
      "Column indices must be less than the number of columns."
    );
    assert!(
      ptrs
        .as_slice()
        .windows(2)
        .all(|x| does_not_have_duplicates(&indcs.as_slice()[x[0]..x[1]])),
      "Column indices of a row must be unique."
    );
    assert!(
      *ptrs.as_slice().last().unwrap() == data.as_slice().len(),
      "Rows length must end with the nnz."
    );
    assert!(
        ptrs.as_slice().windows(2).all(|x| x[0] <= x[1]),
        "Rows length must be in ascending order."
    );
    unsafe { Self::new_unchecked(shape, data, indcs, ptrs) }
  }

  /// A faster and unsafe version of [`new`](#method.new).
  pub unsafe fn new_unchecked(shape: [usize; 2], data: DS, indcs: US, ptrs: US) -> Self {
    CsrMatrix {
      data,
      dim: shape.into(),
      indcs,
      ptrs,
    }
  }

  /// Converts the inner storage to a generic immutable slice storage.
  ///
  /// # Examples
  ///
  /// ```rust
  /// use mop_structs::{
  ///     doc_tests::csr_matrix_array,
  ///     matrix::csr_matrix::CsrMatrixRef
  /// };
  /// assert_eq!(
  ///     csr_matrix_array().as_ref(),
  ///     CsrMatrixRef::new(
  ///         [4, 5],
  ///         &[1, 2, 3, 4, 5],
  ///         &[0, 2, 1, 3, 4],
  ///         &[0, 2, 4, 4, 5]
  ///     )
  /// );
  /// ```
  pub fn as_ref(&self) -> CsrMatrixRef<'_, DS::Item> {
    CsrMatrix::new(
      [self.dim.rows(), self.dim.cols()],
      self.data.as_slice(),
      self.indcs.as_slice(),
      self.ptrs.as_slice(),
    )
  }

  /// Returns an immutable reference to the data elements.
  ///
  /// # Examples
  ///
  /// ```rust
  /// use mop_structs::doc_tests::csr_matrix_array;
  /// let a = csr_matrix_array();
  /// assert_eq!(a.data(), &[1, 2, 3, 4, 5]);
  /// ```
  pub fn data(&self) -> &[DS::Item] {
    self.data.as_slice()
  }

  /// Returns an immutable reference to the column indices of the data elements.
  ///
  /// # Examples
  ///
  /// ```rust
  /// use mop_structs::doc_tests::csr_matrix_array;
  /// let a = csr_matrix_array();
  /// assert_eq!(a.indcs(), &[0, 2, 1, 3, 4]);
  /// ```
  pub fn indcs(&self) -> &[usize] {
    &self.indcs.as_slice()
  }

  /// Returns the Number of NonZero elements.
  ///
  /// # Examples
  ///
  /// ```rust
  /// use mop_structs::doc_tests::csr_matrix_array;
  /// assert_eq!(csr_matrix_array().nnz(), 5);
  /// ```
  #[inline]
  pub fn nnz(&self) -> usize {
    self.data().len()
  }

  /// Returns an immutable reference to the rows length.
  ///
  /// # Examples
  ///
  /// ```rust
  /// use mop_structs::doc_tests::csr_matrix_array;
  /// let a = csr_matrix_array();
  /// assert_eq!(a.ptrs(), &[0, 2, 4, 4, 5]);
  /// ```
  pub fn ptrs(&self) -> &[usize] {
    &self.ptrs.as_slice()
  }

  /// Returns an immutable reference to the row at the `row_idx` row.
  ///
  /// # Examples
  ///
  /// ```rust
  /// use mop_structs::{
  ///     doc_tests::csr_matrix_array,
  ///     vec::css::CssSlice
  /// };
  /// assert_eq!(
  ///     csr_matrix_array().row(0),
  ///     CssSlice::new(5, &[1, 2], &[0, 2])
  /// );
  /// ```
  ///
  /// # Assertions
  ///
  /// * `row_idx` must be less than the number of rows.
  ///
  /// ```should_panic
  /// use mop_structs::doc_tests::csr_matrix_array;
  /// let _ = csr_matrix_array().row(10);
  /// ```
  pub fn row(&self, row_idx: usize) -> CssSlice<'_, DS::Item> {
    let range = self.ptr_range_of_row(row_idx);
    CssSlice::new(
      self.dim.cols(),
      &self.data.as_slice()[range.clone()],
      &self.indcs.as_slice()[range],
    )
  }

  /// An iterator that returns immutable references of all rows.
  ///
  /// # Examples
  ///
  /// ```rust
  /// use mop_structs::{
  ///     doc_tests::csr_matrix_array,
  ///     vec::css::CssSlice
  /// };
  /// let mut a = csr_matrix_array();
  /// let mut li = a.row_iter();
  /// li.next();
  /// assert_eq!(li.next(), Some(CssSlice::new(5, &[3, 4], &[1, 3])));
  /// li.next();
  /// li.next();
  /// assert_eq!(li.next(), None);
  /// ```
  pub fn row_iter(&self) -> CsrMatrixRowIter<'_, DS::Item> {
    CsrMatrixRowIter::new(
      [self.rows(), self.cols()],
      self.data().as_ptr(),
      self.indcs(),
      self.ptrs(),
    )
  }

  /// An parallel iterator that returns immutable references of all rows.
  ///
  /// # Examples
  ///
  /// ```rust
  /// use mop_structs::{
  ///     doc_tests::csr_matrix_array,
  ///     prelude::*
  /// };
  /// let a = csr_matrix_array();
  /// a.row_par_iter().enumerate().for_each(|(idx, x)| assert_eq!(x, a.row(idx)));
  /// ```
  #[cfg(feature = "rayon")]
  pub fn row_par_iter(
    &self,
  ) -> crate::utils::ParallelIteratorWrapper<CsrMatrixRowIter<'_, DS::Item>> {
    crate::utils::ParallelIteratorWrapper(self.row_iter())
  }

  /// If any, returns an immutable reference to the element at the `row_idx` row and
  /// `col_idx` column.
  ///
  /// # Examples
  ///
  /// ```rust
  /// use mop_structs::doc_tests::csr_matrix_array;
  /// let a = csr_matrix_array();
  /// assert_eq!(a.value(0, 0), Some(&1));
  /// assert_eq!(a.value(1, 0), None);
  /// ```
  ///
  /// # Assertions
  ///
  /// * `row_idx` must be less than the number of rows and `col_idx` must be less
  /// than the number of columns.
  ///
  /// ```should_panic
  /// use mop_structs::doc_tests::csr_matrix_array;
  /// let _ = csr_matrix_array().value(10, 10);
  /// ```
  pub fn value(&self, row_idx: usize, col_idx: usize) -> Option<&DS::Item> {
    self
      .data_idx_of_coords(row_idx, col_idx)
      .map(|x| &self.data()[x])
  }

  #[inline]
  fn data_idx_of_coords(&self, row_idx: usize, col_idx: usize) -> Option<usize> {
    assert!(row_idx < self.rows() && col_idx < self.cols());
    let row_start_ptr = self.ptrs()[row_idx];
    let row_end_ptr = self.ptrs()[row_idx + 1];
    if let Ok(x) = self.indcs()[row_start_ptr..row_end_ptr].binary_search(&col_idx) {
      Some(row_start_ptr + x)
    } else {
      None
    }
  }

  #[inline]
  fn ptr_range_of_row(&self, row_idx: usize) -> Range<usize> {
    assert!(
      row_idx < self.dim.rows(),
      "`row_idx` must be less than the number of rows."
    );
    let lower_bound = self.ptrs()[row_idx] - self.ptrs()[0];
    let upper_bound = self.ptrs()[row_idx + 1] - self.ptrs()[0];
    lower_bound..upper_bound
  }
}

#[cfg(feature = "rand")]
impl<DS, US> CsrMatrix<DS, US>
where
  DS: StDenseStoRef,
  US: StDenseStoRef<Item = usize>,
{
}

impl<DS, US> CsrMatrix<DS, US>
where
  DS: StDenseStoMut,
  US: StDenseStoRef<Item = usize>,
{
  /// Returns an mutable reference to the data elements.
  ///
  /// # Examples
  ///
  /// ```rust
  /// use mop_structs::doc_tests::csr_matrix_array;
  /// let mut a = csr_matrix_array();
  /// assert_eq!(a.data_mut(), &mut [1, 2, 3, 4, 5]);
  /// ```
  pub fn data_mut(&mut self) -> &mut [DS::Item] {
    self.data.as_mut_slice()
  }

  /// In a single borrow of `Self`, returns borrows for the most imporant inner
  /// parts (&mut data, &indices and &pointers).
  pub fn parts_with_data_mut(&mut self) -> (&mut [DS::Item], &[usize], &[usize]) {
    (
      self.data.as_mut_slice(),
      self.indcs.as_slice(),
      self.ptrs.as_slice(),
    )
  }

  /// Returns an mutable reference to the row at the `row_idx` position.
  ///
  /// # Examples
  ///
  /// ```rust
  /// use mop_structs::{
  ///     doc_tests::csr_matrix_array,
  ///     vec::css::CssSliceMut
  /// };
  /// assert_eq!(
  ///     csr_matrix_array().row_mut(1),
  ///     CssSliceMut::new(5, &mut [3, 4], &[1, 3])
  /// );
  /// ```
  ///
  /// # Assertions
  ///
  /// * `row_idx` must be less than the number of rows.
  ///
  /// ```should_panic
  /// use mop_structs::doc_tests::csr_matrix_array;
  /// let _ = csr_matrix_array().row_mut(10);
  /// ```
  pub fn row_mut(&mut self, row_idx: usize) -> CssSliceMut<'_, DS::Item> {
    let range = self.ptr_range_of_row(row_idx);
    CssSliceMut::new(
      self.dim.cols(),
      &mut self.data.as_mut_slice()[range.clone()],
      &self.indcs.as_slice()[range],
    )
  }

  /// An iterator that returns mutable references of all rows.
  ///
  /// # Examples
  ///
  /// ```rust
  /// use mop_structs::{
  ///     doc_tests::csr_matrix_array,
  ///     vec::css::CssSliceMut
  /// };
  /// let mut a = csr_matrix_array();
  /// let mut li = a.row_iter_mut();
  /// li.next();
  /// assert_eq!(li.next(), Some(CssSliceMut::new(5, &mut [3, 4], &[1, 3])));
  /// li.next();
  /// li.next();
  /// assert_eq!(li.next(), None);
  /// ```
  pub fn row_iter_mut(&mut self) -> CsrMatrixRowIterMut<'_, DS::Item> {
    CsrMatrixRowIterMut::new(
      [self.rows(), self.cols()],
      self.data_mut().as_mut_ptr(),
      self.indcs(),
      self.ptrs(),
    )
  }

  /// An parallel iterator that returns mutable references of all rows.
  ///
  /// # Examples
  ///
  /// ```rust
  /// use mop_structs::{
  ///     doc_tests::csr_matrix_array,
  ///     prelude::*
  /// };
  /// let mut a = csr_matrix_array();
  /// a.row_par_iter_mut().for_each(|mut a| a.data_mut().iter_mut().for_each(|b| *b += 2));
  /// assert_eq!(a.data(), &[3, 4, 5, 6, 7]);
  /// ```
  #[cfg(feature = "rayon")]
  pub fn row_par_iter_mut(
    &mut self,
  ) -> crate::utils::ParallelIteratorWrapper<CsrMatrixRowIterMut<'_, DS::Item>> {
    crate::utils::ParallelIteratorWrapper(self.row_iter_mut())
  }

  pub fn split_at_mut(
    &mut self,
    row_idx: usize,
  ) -> (CssSliceMut<'_, DS::Item>, CssSliceMut<'_, DS::Item>) {
    assert!(row_idx <= self.rows());
    let split_at = self.ptrs()[row_idx];
    let (first_data, second_data) = self.data.as_mut_slice().split_at_mut(split_at);
    let first = CssSliceMut::new(
      self.dim.cols(),
      first_data,
      &self.indcs.as_slice()[0..split_at],
    );
    let second = CssSliceMut::new(
      self.dim.cols(),
      second_data,
      &self.indcs.as_slice()[split_at..],
    );
    (first, second)
  }

  /// If any, returns an mutable reference to the element at the `row_idx` row and
  /// `col_idx` column.
  ///
  /// # Examples
  ///
  /// ```rust
  /// use mop_structs::doc_tests::csr_matrix_array;
  /// let mut a = csr_matrix_array();
  /// assert_eq!(a.value_mut(0, 0), Some(&mut 1));
  /// assert_eq!(a.value_mut(1, 0), None);
  /// ```
  ///
  /// # Assertions
  ///
  /// * `row_idx` must be less than the number of rows and `col_idx` must be less
  /// than the number of columns.
  ///
  /// ```should_panic
  /// use mop_structs::doc_tests::csr_matrix_array;
  /// let _ = csr_matrix_array().value_mut(10, 10);
  /// ```
  pub fn value_mut(&mut self, row_idx: usize, col_idx: usize) -> Option<&mut DS::Item> {
    if let Some(x) = self.data_idx_of_coords(row_idx, col_idx) {
      Some(&mut self.data_mut()[x])
    } else {
      None
    }
  }

  /// Swaps two elements of two distinct coordinates.
  ///
  /// # Examples
  ///
  /// ```rust
  /// use mop_structs::doc_tests::csr_matrix_array;
  /// let mut a = csr_matrix_array();
  /// a.swap([0, 0], [3, 4]);
  /// assert_eq!(a.data(), &[5, 2, 3, 4, 1]);
  /// ```
  ///
  /// # Assertions
  ///
  /// * `a` row must be less than the number of rows and `a` column must be
  /// less than the number of columns.
  ///
  /// ```should_panic
  /// use mop_structs::doc_tests::csr_matrix_array;
  /// let _ = csr_matrix_array().swap([10, 10], [0, 0]);
  /// ```
  ///
  /// * `b` row must be less than the number of rows and `b` column must be
  /// less than the number of columns.
  ///
  /// ```should_panic
  /// use mop_structs::doc_tests::csr_matrix_array;
  /// let _ = csr_matrix_array().swap([0, 0], [10, 10]);
  /// ```
  ///
  /// * `a` or `b` coordinates must point to existing elements.
  ///
  /// ```should_panic
  /// use mop_structs::doc_tests::csr_matrix_array;
  /// let _ = csr_matrix_array().swap([1, 1], [2, 2]);
  /// ```
  pub fn swap(&mut self, a: [usize; 2], b: [usize; 2]) {
    let a_data_idx = self.data_idx_of_coords(a[0], a[1]).unwrap();
    let b_data_idx = self.data_idx_of_coords(b[0], b[1]).unwrap();
    self.data_mut().swap(a_data_idx, b_data_idx);
  }
}

impl<DS, US> CsrMatrix<DS, US>
where
  DS: DynDenseStoRef,
  US: DynDenseStoRef<Item = usize>,
{
  /// Returns the current rows capacity.
  ///
  /// # Examples
  ///
  /// ```rust
  /// use mop_structs::doc_tests::csr_matrix_vec_array;
  /// assert_eq!(csr_matrix_vec_array().rows_capacity(), 4);
  /// ```
  #[inline]
  pub fn rows_capacity(&self) -> usize {
    self.ptrs.capacity() - 1
  }
}

impl<DS, US> CsrMatrix<DS, US>
where
  DS: DynDenseStoMut,
  US: DynDenseStoMut<Item = usize>,
{
  /// Removes all values and sets the number of rows to zero but doesn't modify the
  /// number of columns.
  ///
  /// Note that this method has no effect on the allocated capacity.
  ///
  /// # Examples
  ///
  /// ```rust
  /// use mop_structs::{
  ///     doc_tests::csr_matrix_vec_array,
  ///     matrix::csr_matrix::CsrMatrixRef,
  ///     prelude::*
  /// };
  /// let mut a = csr_matrix_vec_array();
  /// a.clear();
  /// assert_eq!(a.as_ref(), CsrMatrixRef::new(
  ///     [0, a.cols()],
  ///     &[],
  ///     &[],
  ///     &[0]
  /// ));
  /// ```
  pub fn clear(&mut self) {
    self.data.clear();
    self.indcs.clear();
    self.ptrs.clear();
    self.ptrs.push(0);
    *self.dim.rows_mut() = 0;
  }

  pub fn extend(&mut self, other: &Self)
  where
    DS::Item: Copy,
    US::Item: Copy,
  {
    assert!(
      self.cols() == other.cols(),
      "The number of columns of `Self` must be equal the number of columns of `other`."
    );
    let mut current_ptr = *self.ptrs.as_slice().last().unwrap();
    let mut last_other_ptr = *other.ptrs().first().unwrap();
    other.ptrs().iter().skip(1).for_each(|&x| {
      current_ptr += x - last_other_ptr;
      last_other_ptr = x;
      self.ptrs.push(current_ptr);
    });
    self.data.extend(other.data());
    self.indcs.extend(other.indcs());
    *self.dim.rows_mut() += other.rows();
  }

  /// See [`CsrMatrixRowConstructor`](CsrMatrixRowConstructor) for more information.
  pub fn row_constructor(&mut self) -> CsrMatrixRowConstructor<'_, DS, US> {
    CsrMatrixRowConstructor::new(
      &mut self.dim,
      &mut self.data,
      &mut self.indcs,
      &mut self.ptrs,
    )
  }

  pub fn truncate(&mut self, until_row_idx: usize) {
    self.data.truncate(until_row_idx);
    self.indcs.truncate(until_row_idx);
    self.ptrs.truncate(until_row_idx + 1);
    *self.dim.rows_mut() = until_row_idx;
  }
}

impl<DS, US> Matrix for CsrMatrix<DS, US> {
  /// The number of columns.
  ///
  /// # Examples
  ///
  /// ```rust
  /// use mop_structs::{doc_tests::csr_matrix_array, prelude::*};
  /// assert_eq!(csr_matrix_array().cols(), 5);
  /// ```
  #[inline]
  fn cols(&self) -> usize {
    self.dim.cols()
  }

  /// The number of rows.
  ///
  /// # Examples
  ///
  /// ```rust
  /// use mop_structs::{doc_tests::csr_matrix_array, prelude::*};
  /// assert_eq!(csr_matrix_array().rows(), 4);
  /// ```
  #[inline]
  fn rows(&self) -> usize {
    self.dim.rows()
  }
}

#[cfg(all(feature = "quickcheck", feature = "rand"))]
use mop_common_deps::{
  quickcheck::{Arbitrary, Gen},
  rand::{
    distributions::{Distribution, Standard},
    Rng,
  },
};
#[cfg(all(feature = "quickcheck", feature = "rand"))]
impl<T> Arbitrary for CsrMatrixVec<T>
where
  Standard: Distribution<T>,
  T: Arbitrary,
{
  #[inline]
  fn arbitrary<G>(g: &mut G) -> Self
  where
    G: Gen,
  {
    let rows = g.gen_range(0, g.size());
    let cols = g.gen_range(0, g.size());
    let nnz = g.gen_range(0, rows * cols + 1);
    CsrMatrixVec::new_rnd([rows, cols], nnz, g, |g, _| g.gen())
  }
}