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 crate::algebra::{
    abstr::{Field, Scalar},
    linear::Matrix,
};
use std::ops::Sub;

impl<T> Sub for Matrix<T>
    where T: Field + Scalar
{
    type Output = Matrix<T>;

    /// Subtracts two matrices
    ///
    /// A = (a_{ij}) \in T^{m \times n}
    /// B = (b_{ij}) \in T^{m \times n}
    /// A - B = ( a_{ij} - b_{ij} )
    ///
    /// # Arguments
    ///
    /// rhs:
    ///
    /// # Example
    ///
    /// ```
    /// use mathru::algebra::linear::Matrix;
    ///
    /// let a: Matrix<f64> = Matrix::new(2, 2, vec![1.0, 0.0, 3.0, -7.0]);
    /// let b: Matrix<f64> = Matrix::new(2, 2, vec![1.0, 0.0, 3.0, -7.0]);
    ///
    /// let c: Matrix<f64> = a - b;
    /// ```
    fn sub(self, rhs: Self) -> Self::Output
    {
        (&self).sub(&rhs)
    }
}

impl<'a, 'b, T> Sub<&'b Matrix<T>> for &'a Matrix<T>
    where T: Field + Scalar
{
    type Output = Matrix<T>;

    fn sub(self, rhs: &'b Matrix<T>) -> Self::Output
    {
        assert_eq!(self.dim(), rhs.dim());
        let (m, n) = rhs.dim();
        Matrix { m,
                 n,
                 data: self.data
                           .iter()
                           .zip(rhs.data.iter())
                           .map(|(x, y)| *x - *y)
                           .collect::<Vec<T>>() }
    }
}

impl<'a, 'b, T> Sub<&'b Matrix<T>> for &'a mut Matrix<T>
    where T: Field + Scalar
{
    type Output = &'a mut Matrix<T>;

    fn sub(self, rhs: &'b Matrix<T>) -> Self::Output
    {
        assert_eq!(self.dim(), rhs.dim());
        self.data.iter_mut().zip(rhs.data.iter()).for_each(|(x, y)| *x -= *y);
        self
    }
}

///
/// Subtracts scalar from all matrix elements
impl<'a, 'b, T> Sub<&'b T> for &'a Matrix<T>
    where T: Field + Scalar
{
    type Output = Matrix<T>;

    /// Subtracts a scalar value from all matrix elements
    ///
    /// # Example
    ///
    /// ```
    /// use mathru::algebra::linear::Matrix;
    ///
    /// let a: Matrix<f64> = Matrix::new(2, 2, vec![1.0, 0.0, 3.0, -7.0]);
    /// let b: Matrix<f64> = &a - &-4.0;
    /// ```
    fn sub(self, rhs: &T) -> Self::Output
    {
        self.apply(&|x: &T| -> T { *x - *rhs })
    }
}

///
/// Subtracts scalar from all matrix elements
impl<'a, 'b, T> Sub<&'b T> for &'a mut Matrix<T>
    where T: Field + Scalar
{
    type Output = &'a mut Matrix<T>;

    /// Subtracts a scalar value from all matrix elements
    ///
    /// # Example
    ///
    /// ```
    /// use mathru::algebra::linear::Matrix;
    ///
    /// let a: Matrix<f64> = Matrix::new(2, 2, vec![1.0, 0.0, 3.0, -7.0]);
    /// let b: Matrix<f64> = &a - &-4.0;
    /// ```
    fn sub(self, rhs: &T) -> Self::Output
    {
        let _ = self.data.iter_mut().for_each(&|x: &mut T| *x -= *rhs);
        self
    }
}

impl<T> Sub<T> for Matrix<T>
    where T: Field + Scalar
{
    type Output = Matrix<T>;

    /// Subtracts a scalar from all matrix elements
    ///
    /// # Example
    ///
    /// ```
    /// use mathru::algebra::linear::Matrix;
    ///
    /// let a: Matrix<f64> = Matrix::new(2, 2, vec![1.0, 0.0, 3.0, -7.0]);
    /// let b: Matrix<f64> = a - -4.0;
    /// ```
    fn sub(self, rhs: T) -> Self::Output
    {
        (&self).sub(&rhs)
    }
}