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

use std::ops::Range;


/// Array Shape Structure
#[derive(Clone)]
pub struct Shape {
    shape: Vec<i32>,
    strides: Vec<usize>,
    start: usize,
    end: usize,
}


impl Shape {
    /// Returns shape products for easier converting indices to linear index
    ///
    /// # Arguments
    ///
    /// * `shape` - Shape to calculate products for
    fn calculate_strides(shape: &Vec<i32>) -> Vec<usize> {
        let len = shape.len();
        let mut products: Vec<usize> = vec![1; len];
        let mut accumulator = 1;

        for i in (0..(len - 1)).rev() {
            accumulator *= shape[i + 1] as usize;
            products[i] = accumulator;
        }

        return products;
    }

    /// Returns new Shape
    ///
    /// # Arguments
    ///
    /// * `shape` - Initial shape matrix
    pub fn new(shape: Vec<i32>, start: usize, end: usize) -> Shape {
        let strides = Shape::calculate_strides(&shape);

        if Shape::len(&shape, &strides) != (end - start) as i32 {
            panic!(
                "Invalid shape given: shape size {}, data size {}",
                Shape::len(&shape, &strides),
                end - start
            );
        }

        return Shape { strides, shape, start, end };
    }

    /// Sets shape
    ///
    /// # Arguments
    ///
    /// * `shape` - New shape matrix
    pub fn set_shape(&mut self, shape: Vec<i32>) -> () {
        self.strides = Shape::calculate_strides(&shape);

        if Shape::len(&shape, &self.strides) != (self.end - self.start) as i32 {
            panic!(
                "Invalid shape given: shape size {}, data size {}",
                Shape::len(&shape, &self.strides),
                self.end - self.start
            );
        }

        self.shape = shape;
    }

    /// Returns shape
    #[inline]
    pub fn get_shape(&self) -> &Vec<i32> {
        return &self.shape;
    }

    /// Converts vector of indices to Shape
    ///
    /// # Arguments
    ///
    /// * `indices` - Indices
    ///
    /// # Example
    pub fn indices_to_shape(&self, indices: Vec<usize>) -> Shape {
        let indices_len = indices.len();
        let shape_len = self.shape.len();
        let indices_len_half = indices_len / 2;

        let mut offset = self.start;

        for i in 0..indices_len_half {
            offset += indices[i * 2] * self.strides[i];
        }

        let shape = if indices[indices_len - 1] != 0 {
            let mut tmp: Vec<i32> = Vec::with_capacity(shape_len - indices_len_half + 1);
            tmp.push((indices[indices_len - 1] - indices[indices_len - 2]) as i32);
            tmp.extend(self.shape.iter().skip(indices_len_half));
            tmp
        } else if indices_len_half == shape_len {
            vec![1]
        } else {
            self.shape[indices_len_half..shape_len].to_vec()
        };

        let count = shape[0] as usize * self.strides[shape_len - shape.len()];
        let end = offset + count;


        return Shape::new(shape, offset as usize, end);
    }

    /// Returns bounds of shape
    #[inline]
    pub fn get_bounds(&self) -> Range<usize> {
        return self.start..self.end;
    }

    /// Returns total number of elements from shape and strides
    ///
    /// # Arguments
    ///
    /// * `shape` - shape vector
    /// * `strides` - strides vector
    #[inline]
    fn len(shape: &Vec<i32>, strides: &Vec<usize>) -> i32 {
        return shape[0] * strides[0] as i32;
    }

    /// Returns total number of elements from shape
    ///
    /// # Arguments
    ///
    /// * `shape` - Array shape
    #[inline]
    pub fn total_len(&self) -> usize {
        return Shape::len(&self.shape, &self.strides) as usize;
    }
}