Initial draft for into_row_iter and into_column_iter

https://github.com/dimforge/nalgebra/issues/834

src/base/allocator.rs

@@ -18,7 +18,7 @@ use crate::base::{DefaultAllocator, Scalar};
 /// same `Buffer` type.
 pub trait Allocator<N: Scalar, R: Dim, C: Dim = U1>: Any + Sized {
     /// The type of buffer this allocator can instanciate.
-    type Buffer: ContiguousStorageMut<N, R, C> + Clone;
+    type Buffer: ContiguousStorageMut<N, R, C> + Clone + IntoIterator<Item=N>;
 
     /// Allocates a buffer with the given number of rows and columns without initializing its content.
     unsafe fn allocate_uninitialized(nrows: R, ncols: C) -> Self::Buffer;

src/base/array_storage.rs

@@ -46,6 +46,20 @@ where
     data: GenericArray<N, Prod<R::Value, C::Value>>,
 }
 
+impl<N, R, C> IntoIterator for ArrayStorage<N, R, C>
+where
+    R: DimName,
+    C: DimName,
+    R::Value: Mul<C::Value>,
+    Prod<R::Value, C::Value>: ArrayLength<N>,
+{
+    type Item = N;
+    type IntoIter = <GenericArray<N, Prod<R::Value, C::Value>> as IntoIterator>::IntoIter;
+    fn into_iter(self) -> Self::IntoIter {
+        self.data.into_iter()
+    }
+}
+
 #[deprecated(note = "renamed to `ArrayStorage`")]
 /// Renamed to [ArrayStorage].
 pub type MatrixArray<N, R, C> = ArrayStorage<N, R, C>;

src/base/conversion.rs

@@ -21,7 +21,7 @@ use crate::base::dimension::{
     Dim, DimName, U1, U10, U11, U12, U13, U14, U15, U16, U2, U3, U4, U5, U6, U7, U8, U9,
 };
 use crate::base::iter::{MatrixIter, MatrixIterMut};
-use crate::base::storage::{ContiguousStorage, ContiguousStorageMut, Storage, StorageMut};
+use crate::base::storage::{ContiguousStorage, ContiguousStorageMut, Storage, StorageMut, Owned};
 use crate::base::{
     ArrayStorage, DVectorSlice, DVectorSliceMut, DefaultAllocator, Matrix, MatrixMN, MatrixSlice,
     MatrixSliceMut, Scalar,
@@ -86,6 +86,17 @@ where
     }
 }
 
+impl<N: Scalar, R: Dim, C: Dim> IntoIterator for Matrix<N, R, C, Owned<N, R, C>>
+    where DefaultAllocator: Allocator<N, R, C>
+{
+    type Item = N;
+    type IntoIter = <Owned<N, R, C> as IntoIterator>::IntoIter;
+
+    #[inline]
+    fn into_iter(self) -> Self::IntoIter {
+        <Owned<N, R, C> as IntoIterator>::into_iter(self.data)
+    }
+}
 impl<'a, N: Scalar, R: Dim, C: Dim, S: Storage<N, R, C>> IntoIterator for &'a Matrix<N, R, C, S> {
     type Item = &'a N;
     type IntoIter = MatrixIter<'a, N, R, C, S>;

src/base/iter.rs

@@ -3,9 +3,9 @@
 use std::marker::PhantomData;
 use std::mem;
 
-use crate::base::dimension::{Dim, U1};
-use crate::base::storage::{Storage, StorageMut};
-use crate::base::{Matrix, MatrixSlice, MatrixSliceMut, Scalar};
+use crate::base::dimension::{Dim, U1, Dynamic};
+use crate::base::storage::{Storage, StorageMut, Owned};
+use crate::base::{Matrix, MatrixSlice, MatrixSliceMut, Scalar, Vector, RowVector};
 
 macro_rules! iterator {
     (struct $Name:ident for $Storage:ident.$ptr: ident -> $Ptr:ty, $Ref:ty, $SRef: ty) => {
@@ -237,6 +237,58 @@ impl<'a, N: Scalar, R: Dim, C: Dim, S: 'a + StorageMut<N, R, C>> ExactSizeIterat
     }
 }
 
+/// An owned iterator through the rows of a matrix.
+pub struct OwnedRowIter<N: Scalar> {
+    rows: std::vec::IntoIter<RowVector<N, Dynamic, Owned<N, U1, Dynamic>>>,
+}
+
+impl<N: Scalar> OwnedRowIter<N> {
+    pub(crate) fn new(mat: Matrix<N, Dynamic, Dynamic, Owned<N, Dynamic, Dynamic>>) -> Self {
+        let ncols = mat.ncols();
+        let nrows = mat.nrows();
+        let mut rows: Vec<Vec<N>> = vec![Vec::with_capacity(ncols); nrows];
+        let mut i = 0;
+        for item in mat.into_iter() {
+            rows[i % nrows].push(item);
+            i += 1;
+        }
+        let rows: Vec<RowVector<N, Dynamic, Owned<N, U1, Dynamic>>> =
+            rows.into_iter()
+                .map(|row| RowVector::<N, Dynamic, Owned<N, U1, Dynamic>>::from_iterator_generic(
+                        U1::from_usize(1), Dynamic::from_usize(ncols), row.into_iter()))
+                .collect();
+        OwnedRowIter { rows: rows.into_iter() }
+    }
+}
+
+impl<N: Scalar> Iterator for OwnedRowIter<N> {
+    type Item = RowVector<N, Dynamic, Owned<N, U1, Dynamic>>;
+
+    #[inline]
+    fn next(&mut self) -> Option<Self::Item> {
+        self.rows.next()
+    }
+
+    #[inline]
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        self.rows.size_hint()
+    }
+
+    #[inline]
+    fn count(self) -> usize {
+        self.rows.count()
+    }
+}
+
+impl<N: Scalar> ExactSizeIterator
+    for OwnedRowIter<N>
+{
+    #[inline]
+    fn len(&self) -> usize {
+        self.rows.len()
+    }
+}
+
 /*
  *
  * Column iterators.
@@ -350,3 +402,59 @@ impl<'a, N: Scalar, R: Dim, C: Dim, S: 'a + StorageMut<N, R, C>> ExactSizeIterat
         self.ncols() - self.curr
     }
 }
+
+/// An owned iterator through the rows of a matrix.
+pub struct OwnedColumnIter<N: Scalar> {
+    cols: std::vec::IntoIter<Vector<N, Dynamic, Owned<N, Dynamic, U1>>>,
+}
+
+impl<N: Scalar> OwnedColumnIter<N> {
+    pub(crate) fn new(mat: Matrix<N, Dynamic, Dynamic, Owned<N, Dynamic, Dynamic>>) -> Self {
+        let ncols = mat.ncols();
+        let nrows = mat.nrows();
+        let mut cols: Vec<Vec<N>> = vec![Vec::with_capacity(nrows); ncols];
+        let mut i = 0;
+        for item in mat.into_iter() {
+            cols[i / nrows].push(item);
+            i += 1;
+        }
+        let cols: Vec<Vector<N, Dynamic, Owned<N, Dynamic, U1>>> =
+            cols.into_iter()
+                .map(|col|
+                    Vector::<N, Dynamic, Owned<N, Dynamic, U1>>::from_iterator_generic(
+                        Dynamic::from_usize(nrows),
+                        U1::from_usize(1),
+                        col.into_iter()
+                    )
+                )
+                .collect();
+        OwnedColumnIter { cols: cols.into_iter() }
+    }
+}
+
+impl<N: Scalar> Iterator for OwnedColumnIter<N> {
+    type Item = Vector<N, Dynamic, Owned<N, Dynamic, U1>>;
+
+    #[inline]
+    fn next(&mut self) -> Option<Self::Item> {
+        self.cols.next()
+    }
+
+    #[inline]
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        self.cols.size_hint()
+    }
+
+    #[inline]
+    fn count(self) -> usize {
+        self.cols.count()
+    }
+}
+
+impl<N: Scalar> ExactSizeIterator
+    for OwnedColumnIter<N> {
+    #[inline]
+    fn len(&self) -> usize {
+        self.cols.len()
+    }
+}

src/base/matrix.rs

@@ -21,12 +21,12 @@ use simba::simd::SimdPartialOrd;
 
 use crate::base::allocator::{Allocator, SameShapeAllocator, SameShapeC, SameShapeR};
 use crate::base::constraint::{DimEq, SameNumberOfColumns, SameNumberOfRows, ShapeConstraint};
-use crate::base::dimension::{Dim, DimAdd, DimSum, IsNotStaticOne, U1, U2, U3};
+use crate::base::dimension::{Dim, DimAdd, DimSum, IsNotStaticOne, U1, U2, U3, Dynamic};
 use crate::base::iter::{
-    ColumnIter, ColumnIterMut, MatrixIter, MatrixIterMut, RowIter, RowIterMut,
+    ColumnIter, ColumnIterMut, OwnedColumnIter, MatrixIter, MatrixIterMut, RowIter, RowIterMut, OwnedRowIter,
 };
 use crate::base::storage::{
-    ContiguousStorage, ContiguousStorageMut, Owned, SameShapeStorage, Storage, StorageMut,
+    ContiguousStorage, ContiguousStorageMut, SameShapeStorage, Storage, StorageMut, Owned
 };
 use crate::base::{DefaultAllocator, MatrixMN, MatrixN, Scalar, Unit, VectorN};
 use crate::SimdComplexField;
@@ -859,6 +859,45 @@ impl<N: Scalar, R: Dim, C: Dim, S: Storage<N, R, C>> Matrix<N, R, C, S> {
     }
 }
 
+impl<N: Scalar> Matrix<N, Dynamic, Dynamic, Owned<N, Dynamic, Dynamic>> {
+    /// Move rows of this matrix into an owned iterator.
+    ///
+    /// # Example
+    /// ```
+    /// # use nalgebra::DMatrix;
+    /// let values = vec![1, 4, 2, 5, 3, 6].into_iter();
+    /// let mut a = DMatrix::from_iterator(2, 3, values);
+    /// let c = a.clone();
+    /// for (i, row) in a.into_row_iter().enumerate() {
+    ///     for (v1, &v2) in row.into_iter().zip(c.row(i).iter()) {
+    ///         assert_eq!(v1, v2)
+    ///     }
+    /// }
+    /// ```
+    #[inline]
+    pub fn into_row_iter(self) -> OwnedRowIter<N> {
+        OwnedRowIter::new(self)
+    }
+
+    /// Move columns of this matrix into an owned iterator.
+    /// # Example
+    /// ```
+    /// # use nalgebra::DMatrix;
+    /// let values = vec![1, 4, 2, 5, 3, 6].into_iter();
+    /// let mut a = DMatrix::from_iterator(2, 3, values);
+    /// let c = a.clone();
+    /// for (i, column) in a.into_column_iter().enumerate() {
+    ///     for (v1, &v2) in column.into_iter().zip(c.column(i).iter()) {
+    ///         assert_eq!(v1, v2)
+    ///     }
+    /// }
+    /// ```
+    #[inline]
+    pub fn into_column_iter(self) -> OwnedColumnIter<N> {
+        OwnedColumnIter::new(self)
+    }
+}
+
 /// # Iteration on components, rows, and columns
 impl<N: Scalar, R: Dim, C: Dim, S: Storage<N, R, C>> Matrix<N, R, C, S> {
     /// Iterates through this matrix coordinates in column-major order.

src/base/vec_storage.rs

@@ -31,6 +31,18 @@ pub struct VecStorage<N, R: Dim, C: Dim> {
     ncols: C,
 }
 
+impl<N, R, C> IntoIterator for VecStorage<N, R, C>
+where
+    R: Dim,
+    C: Dim,
+{
+    type Item = N;
+    type IntoIter = <Vec<N> as IntoIterator>::IntoIter;
+    fn into_iter(self) -> Self::IntoIter {
+        self.data.into_iter()
+    }
+}
+
 #[deprecated(note = "renamed to `VecStorage`")]
 /// Renamed to [VecStorage].
 pub type MatrixVec<N, R, C> = VecStorage<N, R, C>;