Determinant and permanent: Difference between revisions

=={{header|Rust}==

{{trans|Java}}

<lang rust>

fn main() {

let mut m1: Vec<Vec<f64>> = vec![vec![1.0,2.0],vec![3.0,4.0]];

let mut r_m1 = &mut m1;

let rr_m1 = &mut r_m1;

let mut m2: Vec<Vec<f64>> = vec![vec![1.0, 2.0, 3.0, 4.0], vec![4.0, 5.0, 6.0, 7.0], vec![7.0, 8.0, 9.0, 10.0], vec![10.0, 11.0, 12.0, 13.0]];

let mut r_m2 = &mut m2;

let rr_m2 = &mut r_m2;

let mut m3: Vec<Vec<f64>> = vec![vec![0.0, 1.0, 2.0, 3.0, 4.0],

vec![5.0, 6.0, 7.0, 8.0, 9.0],

vec![10.0, 11.0, 12.0, 13.0, 14.0],

vec![15.0, 16.0, 17.0, 18.0, 19.0],

vec![20.0, 21.0, 22.0, 23.0, 24.0]];

let mut r_m3 = &mut m3;

let rr_m3 = &mut r_m3;

println!("Determinant of m1: {}", determinant(rr_m1));

println!("Permanant of m1: {}", permanent(rr_m1));

println!("Determinant of m2: {}", determinant(rr_m2));

println!("Permanant of m2: {}", permanent(rr_m2));

println!("Determinant of m3: {}", determinant(rr_m3));

println!("Permanant of m3: {}", permanent(rr_m3));

}

fn minor( a: &mut Vec<Vec<f64>>, x: usize, y: usize) -> Vec<Vec<f64>> {

let mut out_vec: Vec<Vec<f64>> = vec![vec![0.0; a.len() - 1]; a.len() -1];

for i in 0..a.len()-1 {

for j in 0..a.len()-1 {

match () {

_ if (i < x && j < y) => {

out_vec[i][j] = a[i][j];

},

_ if (i >= x && j < y) => {

out_vec[i][j] = a[i + 1][j];

},

_ if (i < x && j >= y) => {

out_vec[i][j] = a[i][j + 1];

},

_ => { //i > x && j > y

out_vec[i][j] = a[i + 1][j + 1];

},

}

}

}

out_vec

}

fn determinant (matrix: &mut Vec<Vec<f64>>) -> f64 {

match () {

_ if (matrix.len() == 1) => {

matrix[0][0]

},

_ => {

let mut sign = 1.0;

let mut sum = 0.0;

for i in 0..matrix.len() {

sum = sum + sign * matrix[0][i] * determinant(&mut minor(matrix, 0, i));

sign = sign * -1.0;

}

sum

}

}

}

fn permanent (matrix: &mut Vec<Vec<f64>>) -> f64 {

match () {

_ if (matrix.len() == 1) => {

matrix[0][0]

},

_ => {

let mut sum = 0.0;

for i in 0..matrix.len() {

sum = sum + matrix[0][i] * permanent(&mut minor(matrix, 0, i));

}

sum

}

}

}

</lang>

{{Output}}

<pre>

Determinant of m1: -2

Permanant of m1: 10

Determinant of m2: 0

Permanant of m2: 29556

Determinant of m3: 0

Permanant of m3: 6778800

</pre>