ndarray/
impl_dyn.rs

1// Copyright 2018 bluss and ndarray developers.
2//
3// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
4// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
5// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
6// option. This file may not be copied, modified, or distributed
7// except according to those terms.
8
9//! Methods for dynamic-dimensional arrays.
10use crate::imp_prelude::*;
11
12/// # Methods for Dynamic-Dimensional Arrays
13impl<A> LayoutRef<A, IxDyn>
14{
15    /// Insert new array axis of length 1 at `axis`, modifying the shape and
16    /// strides in-place.
17    ///
18    /// **Panics** if the axis is out of bounds.
19    ///
20    /// ```
21    /// use ndarray::{Axis, arr2, arr3};
22    ///
23    /// let mut a = arr2(&[[1, 2, 3], [4, 5, 6]]).into_dyn();
24    /// assert_eq!(a.shape(), &[2, 3]);
25    ///
26    /// a.insert_axis_inplace(Axis(1));
27    /// assert_eq!(a, arr3(&[[[1, 2, 3]], [[4, 5, 6]]]).into_dyn());
28    /// assert_eq!(a.shape(), &[2, 1, 3]);
29    /// ```
30    #[track_caller]
31    pub fn insert_axis_inplace(&mut self, axis: Axis)
32    {
33        assert!(axis.index() <= self.ndim());
34        self.0.dim = self._dim().insert_axis(axis);
35        self.0.strides = self._strides().insert_axis(axis);
36    }
37
38    /// Collapses the array to `index` along the axis and removes the axis,
39    /// modifying the shape and strides in-place.
40    ///
41    /// **Panics** if `axis` or `index` is out of bounds.
42    ///
43    /// ```
44    /// use ndarray::{Axis, arr1, arr2};
45    ///
46    /// let mut a = arr2(&[[1, 2, 3], [4, 5, 6]]).into_dyn();
47    /// assert_eq!(a.shape(), &[2, 3]);
48    ///
49    /// a.index_axis_inplace(Axis(1), 1);
50    /// assert_eq!(a, arr1(&[2, 5]).into_dyn());
51    /// assert_eq!(a.shape(), &[2]);
52    /// ```
53    #[track_caller]
54    pub fn index_axis_inplace(&mut self, axis: Axis, index: usize)
55    {
56        self.collapse_axis(axis, index);
57        self.0.dim = self._dim().remove_axis(axis);
58        self.0.strides = self._strides().remove_axis(axis);
59    }
60}
61
62impl<S: RawData> ArrayBase<S, IxDyn>
63{
64    /// Insert new array axis of length 1 at `axis`, modifying the shape and
65    /// strides in-place.
66    ///
67    /// **Panics** if the axis is out of bounds.
68    ///
69    /// ```
70    /// use ndarray::{Axis, arr2, arr3};
71    ///
72    /// let mut a = arr2(&[[1, 2, 3], [4, 5, 6]]).into_dyn();
73    /// assert_eq!(a.shape(), &[2, 3]);
74    ///
75    /// a.insert_axis_inplace(Axis(1));
76    /// assert_eq!(a, arr3(&[[[1, 2, 3]], [[4, 5, 6]]]).into_dyn());
77    /// assert_eq!(a.shape(), &[2, 1, 3]);
78    /// ```
79    #[track_caller]
80    pub fn insert_axis_inplace(&mut self, axis: Axis)
81    {
82        self.as_mut().insert_axis_inplace(axis)
83    }
84
85    /// Collapses the array to `index` along the axis and removes the axis,
86    /// modifying the shape and strides in-place.
87    ///
88    /// **Panics** if `axis` or `index` is out of bounds.
89    ///
90    /// ```
91    /// use ndarray::{Axis, arr1, arr2};
92    ///
93    /// let mut a = arr2(&[[1, 2, 3], [4, 5, 6]]).into_dyn();
94    /// assert_eq!(a.shape(), &[2, 3]);
95    ///
96    /// a.index_axis_inplace(Axis(1), 1);
97    /// assert_eq!(a, arr1(&[2, 5]).into_dyn());
98    /// assert_eq!(a.shape(), &[2]);
99    /// ```
100    #[track_caller]
101    pub fn index_axis_inplace(&mut self, axis: Axis, index: usize)
102    {
103        self.as_mut().index_axis_inplace(axis, index)
104    }
105}
106
107impl<A, S> ArrayBase<S, IxDyn>
108where S: Data<Elem = A>
109{
110    /// Remove axes of length 1 and return the modified array.
111    ///
112    /// If the array has more the one dimension, the result array will always
113    /// have at least one dimension, even if it has a length of 1.
114    ///
115    /// ```
116    /// use ndarray::{arr1, arr2, arr3};
117    ///
118    /// let a = arr3(&[[[1, 2, 3]], [[4, 5, 6]]]).into_dyn();
119    /// assert_eq!(a.shape(), &[2, 1, 3]);
120    /// let b = a.squeeze();
121    /// assert_eq!(b, arr2(&[[1, 2, 3], [4, 5, 6]]).into_dyn());
122    /// assert_eq!(b.shape(), &[2, 3]);
123    ///
124    /// let c = arr2(&[[1]]).into_dyn();
125    /// assert_eq!(c.shape(), &[1, 1]);
126    /// let d = c.squeeze();
127    /// assert_eq!(d, arr1(&[1]).into_dyn());
128    /// assert_eq!(d.shape(), &[1]);
129    /// ```
130    #[track_caller]
131    pub fn squeeze(self) -> Self
132    {
133        let mut out = self;
134        for axis in (0..out.shape().len()).rev() {
135            if out.shape()[axis] == 1 && out.shape().len() > 1 {
136                out = out.remove_axis(Axis(axis));
137            }
138        }
139        out
140    }
141}
142
143#[cfg(test)]
144mod tests
145{
146    use crate::{arr1, arr2, arr3};
147
148    #[test]
149    fn test_squeeze()
150    {
151        let a = arr3(&[[[1, 2, 3]], [[4, 5, 6]]]).into_dyn();
152        assert_eq!(a.shape(), &[2, 1, 3]);
153
154        let b = a.squeeze();
155        assert_eq!(b, arr2(&[[1, 2, 3], [4, 5, 6]]).into_dyn());
156        assert_eq!(b.shape(), &[2, 3]);
157
158        let c = arr2(&[[1]]).into_dyn();
159        assert_eq!(c.shape(), &[1, 1]);
160
161        let d = c.squeeze();
162        assert_eq!(d, arr1(&[1]).into_dyn());
163        assert_eq!(d.shape(), &[1]);
164    }
165}
ndarray/impl_dyn.rs

ndarray/
impl_dyn.rs
