From 0ed67d047065343817bdcde62cfaf928a8c88519 Mon Sep 17 00:00:00 2001
From: Jack Wrenn <me@jswrenn.com>
Date: Tue, 13 Nov 2018 16:17:00 -0500
Subject: [PATCH] Implement `Extend<Vector<_,_,_>>` for `Matrix`.

Extend a `Matrix` with columns drawn from an iterator of `Vector`s.
---
 src/base/edition.rs    | 63 ++++++++++++++++++++++++++++++++++++++++++
 src/base/matrix_vec.rs | 30 +++++++++++++++++++-
 2 files changed, 92 insertions(+), 1 deletion(-)

diff --git a/src/base/edition.rs b/src/base/edition.rs
index 4384da39..28230752 100644
--- a/src/base/edition.rs
+++ b/src/base/edition.rs
@@ -772,3 +772,66 @@ where
         self.data.extend(iter);
     }
 }
+
+impl<N, R, S, RV, SV> Extend<Vector<N, RV, SV>> for Matrix<N, R, Dynamic, S>
+where
+    N: Scalar,
+    R: Dim,
+    S: Extend<Vector<N, RV, SV>>,
+    RV: Dim,
+    SV: Storage<N, RV>
+{
+    /// Extends the number of columns of a `Matrix` with `Vector`s
+    /// from a given iterator.
+    ///
+    /// # Example
+    /// ```
+    /// # use nalgebra::{DMatrix, Vector3, Matrix3x4};
+    ///
+    /// let data = vec![0, 1, 2,          // column 1
+    ///                 3, 4, 5];         // column 2
+    ///
+    /// let mut matrix = DMatrix::from_vec(3, 2, data);
+    ///
+    /// matrix.extend(
+    ///   vec![Vector3::new(6,  7,  8),   // column 3
+    ///        Vector3::new(9, 10, 11)]); // column 4
+    ///
+    /// assert!(matrix.eq(&Matrix3x4::new(0, 3, 6,  9,
+    ///                                   1, 4, 7, 10,
+    ///                                   2, 5, 8, 11)));
+    /// ```
+    ///
+    /// # Panics
+    /// This function panics if the dimension of each `Vector` yielded
+    /// by the given iterator is not equal to the number of rows of
+    /// this `Matrix`.
+    ///
+    /// ```should_panic
+    /// # use nalgebra::{DMatrix, Vector2, Matrix3x4};
+    /// let mut matrix =
+    ///   DMatrix::from_vec(3, 2,
+    ///                     vec![0, 1, 2,   // column 1
+    ///                          3, 4, 5]); // column 2
+    ///
+    /// // The following panics because this matrix can only be extended with 3-dimensional vectors.
+    /// matrix.extend(
+    ///   vec![Vector2::new(6,  7)]); // too few dimensions!
+    /// ```
+    ///
+    /// ```should_panic
+    /// # use nalgebra::{DMatrix, Vector4, Matrix3x4};
+    /// let mut matrix =
+    ///   DMatrix::from_vec(3, 2,
+    ///                     vec![0, 1, 2,   // column 1
+    ///                          3, 4, 5]); // column 2
+    ///
+    /// // The following panics because this matrix can only be extended with 3-dimensional vectors.
+    /// matrix.extend(
+    ///   vec![Vector4::new(6, 7, 8, 9)]); // too few dimensions!
+    /// ```
+    fn extend<I: IntoIterator<Item=Vector<N, RV, SV>>>(&mut self, iter: I)
+    {
+        self.data.extend(iter);
+    }
+}
diff --git a/src/base/matrix_vec.rs b/src/base/matrix_vec.rs
index b821afdb..080ce16e 100644
--- a/src/base/matrix_vec.rs
+++ b/src/base/matrix_vec.rs
@@ -9,7 +9,7 @@ use base::allocator::Allocator;
 use base::default_allocator::DefaultAllocator;
 use base::dimension::{Dim, DimName, Dynamic, U1};
 use base::storage::{ContiguousStorage, ContiguousStorageMut, Owned, Storage, StorageMut};
-use base::Scalar;
+use base::{Scalar, Vector};
 
 #[cfg(feature = "abomonation-serialize")]
 use abomonation::Abomonation;
@@ -259,6 +259,34 @@ impl<N, R: Dim> Extend<N> for MatrixVec<N, R, Dynamic>
     }
 }
 
+impl<N, R, RV, SV> Extend<Vector<N, RV, SV>> for MatrixVec<N, R, Dynamic>
+where
+    N: Scalar,
+    R: Dim,
+    RV: Dim,
+    SV: Storage<N, RV>
+{
+    /// Extends the number of columns of the `MatrixVec` with vectors
+    /// from the given iterator.
+    ///
+    /// # Panics
+    /// This function panics if the number of rows of each `Vector`
+    /// yielded by the iterator is not equal to the number of rows
+    /// of this `MatrixVec`.
+    fn extend<I: IntoIterator<Item=Vector<N, RV, SV>>>(&mut self, iter: I)
+    {
+        let nrows = self.nrows.value();
+        let iter = iter.into_iter();
+        let (lower, _upper) = iter.size_hint();
+        self.data.reserve(nrows * lower);
+        for vector in iter {
+            assert_eq!(nrows, vector.shape().0);
+            self.data.extend(vector.iter());
+        }
+        self.ncols = Dynamic::new(self.data.len() / nrows);
+    }
+}
+
 impl<N> Extend<N> for MatrixVec<N, Dynamic, U1>
 {
     /// Extends the number of rows of the `MatrixVec` with elements