numrs2 0.3.3

A Rust implementation inspired by NumPy for numerical computing (NumRS2)
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256

//! Array concatenation helper functions
//!
//! This module provides convenience functions for array concatenation:
//! - `r_concatenate` - Concatenate arrays along the first axis (np.r_)
//! - `c_concatenate` - Concatenate arrays along columns (np.c_)
//! - `ix_` - Create an open mesh from input arrays (np.ix_)

use crate::array::Array;
use crate::error::{NumRs2Error, Result};

/// Array concatenation helper (equivalent to np.r_)
///
/// Concatenate arrays along the first axis. This provides convenient syntax
/// for concatenating arrays similar to NumPy's r_ indexing.
///
/// # Parameters
///
/// * `arrays` - Arrays to concatenate
///
/// # Returns
///
/// Concatenated array along the first axis
///
/// # Examples
///
/// ```
/// use numrs2::prelude::*;
/// use numrs2::array_ops::creation::r_concatenate;
///
/// let a = Array::from_vec(vec![1, 2, 3]);
/// let b = Array::from_vec(vec![4, 5, 6]);
/// let result = r_concatenate(&[&a, &b]).expect("operation should succeed");
/// assert_eq!(result.to_vec(), vec![1, 2, 3, 4, 5, 6]);
///
/// // 2D arrays
/// let a = Array::from_vec(vec![1, 2, 3, 4]).reshape(&[2, 2]);
/// let b = Array::from_vec(vec![5, 6, 7, 8]).reshape(&[2, 2]);
/// let result = r_concatenate(&[&a, &b]).expect("operation should succeed");
/// assert_eq!(result.shape(), vec![4, 2]);
/// ```
pub fn r_concatenate<T: Clone>(arrays: &[&Array<T>]) -> Result<Array<T>> {
    if arrays.is_empty() {
        return Err(NumRs2Error::InvalidOperation(
            "Cannot concatenate empty array list".to_string(),
        ));
    }

    // Use the existing concatenate function along axis 0
    crate::array_ops::concatenate(arrays, 0)
}

/// Array concatenation helper along columns (equivalent to np.c_)
///
/// Concatenate arrays along the second axis (columns). For 1D arrays,
/// this stacks them as columns.
///
/// # Parameters
///
/// * `arrays` - Arrays to concatenate along columns
///
/// # Returns
///
/// Concatenated array along the second axis (columns)
///
/// # Examples
///
/// ```
/// use numrs2::prelude::*;
/// use numrs2::array_ops::creation::c_concatenate;
///
/// // 1D arrays become columns
/// let a = Array::from_vec(vec![1, 2, 3]);
/// let b = Array::from_vec(vec![4, 5, 6]);
/// let result = c_concatenate(&[&a, &b]).expect("operation should succeed");
/// assert_eq!(result.shape(), vec![3, 2]);
/// // Note: the specific order depends on the internal implementation
///
/// // 2D arrays
/// let a = Array::from_vec(vec![1, 2, 3, 4]).reshape(&[2, 2]);
/// let b = Array::from_vec(vec![5, 6, 7, 8]).reshape(&[2, 2]);
/// let result = c_concatenate(&[&a, &b]).expect("operation should succeed");
/// assert_eq!(result.shape(), vec![2, 4]);
/// ```
pub fn c_concatenate<T: Clone>(arrays: &[&Array<T>]) -> Result<Array<T>> {
    if arrays.is_empty() {
        return Err(NumRs2Error::InvalidOperation(
            "Cannot concatenate empty array list".to_string(),
        ));
    }

    // Convert 1D arrays to column vectors
    let mut column_arrays = Vec::new();
    for &arr in arrays {
        if arr.ndim() == 1 {
            // Reshape 1D array to column vector
            let reshaped = arr.reshape(&[arr.len(), 1]);
            column_arrays.push(reshaped);
        } else {
            column_arrays.push(arr.clone());
        }
    }

    // Get references for concatenation
    let column_refs: Vec<&Array<T>> = column_arrays.iter().collect();

    // Use the existing concatenate function along axis 1
    crate::array_ops::concatenate(&column_refs, 1)
}

/// Create an open mesh from input arrays (equivalent to np.ix_)
///
/// Construct an open mesh from multiple sequences. This function takes N 1-D sequences
/// and returns N N-D arrays. These arrays can be used for vectorized evaluation of
/// N-D scalar/vector fields over N-D grids.
///
/// # Parameters
///
/// * `sequences` - 1-D arrays representing coordinates along each axis
///
/// # Returns
///
/// Vector of N-D arrays where each array has values only along its respective axis
///
/// # Examples
///
/// ```
/// use numrs2::prelude::*;
/// use numrs2::array_ops::creation::ix_;
///
/// let a = Array::from_vec(vec![0, 1, 2]);
/// let b = Array::from_vec(vec![3, 4]);
/// let indices = ix_(&[&a, &b]).expect("operation should succeed");
///
/// assert_eq!(indices.len(), 2);
/// assert_eq!(indices[0].shape(), vec![3, 1]);  // Values for first dimension
/// assert_eq!(indices[1].shape(), vec![1, 2]);  // Values for second dimension
///
/// // Can be used for advanced indexing
/// let x = Array::from_vec(vec![10, 11, 12]);
/// let y = Array::from_vec(vec![20, 30]);
/// let grid_indices = ix_(&[&x, &y]).expect("operation should succeed");
/// ```
pub fn ix_<T: Clone>(sequences: &[&Array<T>]) -> Result<Vec<Array<T>>> {
    if sequences.is_empty() {
        return Ok(vec![]);
    }

    // Verify all inputs are 1D
    for (i, seq) in sequences.iter().enumerate() {
        if seq.ndim() != 1 {
            return Err(NumRs2Error::DimensionMismatch(format!(
                "Input array {} must be 1-D, got {}-D",
                i,
                seq.ndim()
            )));
        }
    }

    let ndim = sequences.len();
    let mut result = Vec::with_capacity(ndim);

    // Create mesh arrays where each array has values only along its axis
    for (axis_idx, &seq) in sequences.iter().enumerate() {
        let mut shape = vec![1; ndim];
        shape[axis_idx] = seq.len();

        let reshaped = seq.reshape(&shape);
        result.push(reshaped);
    }

    Ok(result)
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn test_r_concatenate() {
        // Test 1D arrays
        let a = Array::from_vec(vec![1, 2, 3]);
        let b = Array::from_vec(vec![4, 5, 6]);
        let result = r_concatenate(&[&a, &b]).expect("operation should succeed");
        assert_eq!(result.to_vec(), vec![1, 2, 3, 4, 5, 6]);
        assert_eq!(result.shape(), vec![6]);

        // Test 2D arrays
        let a = Array::from_vec(vec![1, 2, 3, 4]).reshape(&[2, 2]);
        let b = Array::from_vec(vec![5, 6, 7, 8]).reshape(&[2, 2]);
        let result = r_concatenate(&[&a, &b]).expect("operation should succeed");
        assert_eq!(result.shape(), vec![4, 2]);
        assert_eq!(result.to_vec(), vec![1, 2, 3, 4, 5, 6, 7, 8]);

        // Test error on empty input
        let result = r_concatenate::<i32>(&[]);
        assert!(result.is_err());
    }

    #[test]
    fn test_c_concatenate() {
        // Test 1D arrays (become columns)
        let a = Array::from_vec(vec![1, 2, 3]);
        let b = Array::from_vec(vec![4, 5, 6]);
        let result = c_concatenate(&[&a, &b]).expect("operation should succeed");
        assert_eq!(result.shape(), vec![3, 2]);
        // Column-major order: [1, 2, 3, 4, 5, 6] where a and b are stacked as columns
        assert_eq!(result.to_vec(), vec![1, 2, 3, 4, 5, 6]);

        // Test 2D arrays
        let a = Array::from_vec(vec![1, 2, 3, 4]).reshape(&[2, 2]);
        let b = Array::from_vec(vec![5, 6, 7, 8]).reshape(&[2, 2]);
        let result = c_concatenate(&[&a, &b]).expect("operation should succeed");
        assert_eq!(result.shape(), vec![2, 4]);
        assert_eq!(result.to_vec(), vec![1, 3, 2, 4, 5, 7, 6, 8]);

        // Test error on empty input
        let result = c_concatenate::<i32>(&[]);
        assert!(result.is_err());
    }

    #[test]
    fn test_ix_() {
        // Test 2D case
        let a = Array::from_vec(vec![0, 1, 2]);
        let b = Array::from_vec(vec![3, 4]);
        let indices = ix_(&[&a, &b]).expect("operation should succeed");

        assert_eq!(indices.len(), 2);
        assert_eq!(indices[0].shape(), vec![3, 1]);
        assert_eq!(indices[1].shape(), vec![1, 2]);

        // Check values
        assert_eq!(indices[0].to_vec(), vec![0, 1, 2]);
        assert_eq!(indices[1].to_vec(), vec![3, 4]);

        // Test 3D case
        let x = Array::from_vec(vec![10, 11]);
        let y = Array::from_vec(vec![20, 30]);
        let z = Array::from_vec(vec![100]);
        let indices_3d = ix_(&[&x, &y, &z]).expect("operation should succeed");

        assert_eq!(indices_3d.len(), 3);
        assert_eq!(indices_3d[0].shape(), vec![2, 1, 1]);
        assert_eq!(indices_3d[1].shape(), vec![1, 2, 1]);
        assert_eq!(indices_3d[2].shape(), vec![1, 1, 1]);

        // Test empty input
        let empty_indices = ix_::<i32>(&[]).expect("operation should succeed");
        assert_eq!(empty_indices.len(), 0);

        // Test error on non-1D input
        let bad_array = Array::from_vec(vec![1, 2, 3, 4]).reshape(&[2, 2]);
        let result = ix_(&[&bad_array]);
        assert!(result.is_err());
    }
}