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

use crate::arrays::Array;
use crate::ext::vec_ext::{VecInsertAt, VecRemoveAt};
use crate::traits::{
    create::ArrayCreate,
    errors::ArrayError,
    manipulate::{
        ArrayManipulate,
        stack::ArrayStack,
    },
    meta::ArrayMeta,
    types::numeric::Numeric,
    validators::{
        validate_axis::ValidateAxis,
        validate_dimension::ValidateDimension,
        validate_has_error::ValidateHasError,
        validate_shape::ValidateShapeConcat,
    },
};

impl <N: Numeric> ArrayStack<N> for Array<N> {

    fn concatenate(arrs: Vec<Self>, axis: Option<usize>) -> Result<Self, ArrayError> {
        if arrs.is_empty() { Self::empty() }
        else {
            if let Some(axis) = axis { arrs.validate_stack_shapes(axis, axis)?; }

            let (mut arrs, initial) = (arrs.clone(), arrs[0].clone());
            let result = arrs.remove_at(0).into_iter()
                .fold(initial, |a, b| a.append(&b, axis).unwrap());
            Ok(result)
        }
    }

    fn stack(arrs: Vec<Self>, axis: Option<usize>) -> Result<Self, ArrayError> {
        arrs.axis_opt_in_bounds(axis)?;
        if arrs.is_empty() { Self::empty() }
        else if (0..arrs.len() - 1).any(|i| arrs[i].get_shape() != arrs[i + 1].get_shape()) {
            Err(ArrayError::ParameterError { param: "arrs", message: "all input arrays must have the same shape", })
        } else {
            let axis = axis.unwrap_or(0);
            let new_shape = arrs[0].get_shape()?.insert_at(axis, arrs.len());

            let (mut arrs, initial) = (arrs.clone(), arrs[0].clone());
            arrs.remove_at(0).into_iter()
                .fold(initial, |a, b| a.append(&b, Some(axis)).unwrap())
                .reshape(new_shape)
        }
    }

    fn vstack(arrs: Vec<Self>) -> Result<Self, ArrayError> {
        if arrs.is_empty() { Self::empty() }
        else {
            arrs.validate_stack_shapes(0, 0)?;

            let mut new_shape = arrs[0].get_shape()?;
            if new_shape.len() == 1 { new_shape.insert_at(0, arrs.len()); }
            else { new_shape[0] = arrs.iter().fold(0, |a, b| a + b.shape[0]); }

            match Self::concatenate(arrs, Some(0)) {
                Ok(c) => c.reshape(new_shape),
                Err(e) => Err(e),
            }
        }
    }

    fn hstack(arrs: Vec<Self>) -> Result<Self, ArrayError> {
        if arrs.is_empty() { return Self::empty() }
        arrs.iter().map(|a| a.ndim()).collect::<Vec<Result<usize, ArrayError>>>().has_error()?;
        if arrs.iter().all(|arr| arr.ndim().unwrap() == 1) {
            Self::concatenate(arrs, Some(0))
        } else {
            let arrs = arrs.iter()
                .map(|arr| arr.atleast(2)).collect::<Vec<Result<Self, _>>>()
                .has_error()?.into_iter()
                .map(|a| a.unwrap())
                .collect::<Vec<Self<>>>();
            arrs.validate_stack_shapes(1, 0)?;

            let mut new_shape = arrs[0].get_shape()?;
            new_shape[1] = arrs.iter().fold(0, |a, b| a + b.shape[1]);

            match Self::concatenate(arrs, Some(1)) {
                Ok(c) => c.reshape(new_shape),
                Err(e) => Err(e),
            }
        }
    }

    fn dstack(arrs: Vec<Self>) -> Result<Self, ArrayError> {
        if arrs.is_empty() { Self::empty() }
        else {
            let arrs = arrs.iter()
                .map(|arr| arr.atleast(3))
                .collect::<Vec<Result<Self, _>>>()
                .has_error()?.into_iter()
                .map(|a| a.unwrap())
                .collect::<Vec<Self<>>>();
            arrs.validate_stack_shapes(2, 0)?;

            let mut new_shape = arrs[0].get_shape()?;
            new_shape[2] = arrs.iter().fold(0, |a, b| a + b.shape[2]);

            match Self::concatenate(arrs, Some(2)) {
                Ok(c) => c.reshape(new_shape),
                Err(e) => Err(e),
            }
        }
    }

    fn column_stack(arrs: Vec<Self>) -> Result<Self, ArrayError> {
        if arrs.is_empty() { Self::empty() }
        else {
            let (num_rows, mut total_cols) = (arrs[0].shape[0], 0);
            arrs.is_dim_supported(&[1, 2])?;
            if arrs.iter().any(|array| array.shape[0] != num_rows) {
                return Err(ArrayError::ParameterError { param: "arrs", message: "all input arrays must have the same first dimension", });
            }

            arrs.iter().map(|a| a.ndim()).collect::<Vec<Result<usize, ArrayError>>>().has_error()?;
            arrs.iter().for_each(|array| {
                if array.ndim().unwrap() == 1 { total_cols += 1; }
                else { total_cols += array.shape[1]; }
            });

            let (mut new_elements, mut new_col_idx) = (vec![N::ZERO; num_rows * total_cols], 0);
            arrs.iter().for_each(|array| {
                let array_cols = if array.ndim().unwrap() == 1 { 1 } else { array.shape[1] };
                (0 .. num_rows).for_each(|row| {
                    (0..array_cols).for_each(|col| {
                        let src_idx = row * array_cols + col;
                        let dst_idx = row * total_cols + new_col_idx + col;
                        new_elements[dst_idx] = array.elements[src_idx];
                    })
                });
                new_col_idx += array_cols;
            });

            Self::new(new_elements, vec![num_rows, total_cols])
        }
    }

    fn row_stack(arrs: Vec<Self>) -> Result<Self, ArrayError> {
        Self::vstack(arrs)
    }
}