mathrc 0.2.2

Rust Mathematics Library
Documentation 
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use std::ops::{Index, IndexMut};

#[derive(Debug, Clone, PartialEq)]
pub struct Matrix {
    data: Vec<f64>,
    rows: usize,
    cols: usize,
}

impl Matrix {
    pub fn new(
        data: Vec<f64>,
        rows: usize,
        cols: usize
    ) -> Result<Self, String> {
        if data.len()!=(rows*cols) {
            return  Err("invalid matrix size".into())
        }
        Ok(Self {
            data, rows, cols
        })
    }

    pub fn get(
        &self,
        r: usize,
        c: usize,
    ) -> Option<f64> {
        if r >= self.rows || c >= self.cols { return None; }
        Some(self.data[r * self.cols + c])
    }

    pub fn set(
        &mut self,
        r: usize,
        c: usize,
        value: f64,
    ) {
        self.data[r * self.cols + c] = value;
    }

    pub fn add(
        &self,
        other: &Self,
    ) -> Result<Self, String> {

        if self.rows != other.rows || self.cols != other.cols {
            return Err("dimension mismatch".into());
        }

        let data = self.data.iter()
            .zip(other.data.iter())
            .map(|(a,b)| a+b)
            .collect();

        Ok(Self { data, rows: self.rows, cols: self.cols, })
    }

    pub fn mul(
        &self,
        other: &Self,
    ) -> Result<Self, String> {
        if self.cols != other.rows {
            return Err("invalid dimensions".into());
        }

        let mut data = vec![0.0; self.rows * other.cols];

        for r in 0..self.rows {
            for c in 0..other.cols {
                let mut sum = 0.0;
                for k in 0..self.cols {
                    sum +=
                        self[(r,k)]
                            * other[(k,c)];
                }

                data[r * other.cols + c] = sum;
            }
        }

        Ok(Self { data, rows: self.rows, cols: other.cols, })
    }

    pub fn transpose(&self) -> Self {
        let mut data = vec![0.0; self.rows * self.cols];

        for r in 0..self.rows {
            for c in 0..self.cols {
                data[c * self.rows + r] = self[(r,c)];
            }
        }

        Self { data, rows: self.cols, cols: self.rows, }
    }

    pub fn identity(n: usize) -> Self {
        let mut data = vec![0.0; n*n];

        for i in 0..n {
            data[i*n+i] = 1.0;
        }

        Self { data, rows: n, cols: n, }
    }
}

impl Index<(usize, usize)> for Matrix {
    type Output = f64;

    fn index(
        &self,
        index: (usize, usize),
    ) -> &Self::Output {
        let (r, c) = index;

        &self.data[r * self.cols + c]
    }
}

impl IndexMut<(usize, usize)> for Matrix {
    fn index_mut(
        &mut self,
        index: (usize, usize),
    ) -> &mut Self::Output {
        let (r, c) = index;
        &mut self.data[r * self.cols + c]
    }
}

#[cfg(test)]
mod test {
    use crate::matrix::matrix::Matrix;

    #[test]
    fn matrix() {
        let m = Matrix::new(vec!(
                0f64, 1f64, 0f64,
                1f64, 0f64, 1f64,
                1f64, 0f64, 1f64,
                0f64 ,1f64, 0f64
        ), 3, 4);

        println!("{}", m.unwrap().get(1, 2).unwrap())
    }
}