nalgebra/examples/matrix_construction.rs

63 lines
1.8 KiB
Rust

extern crate nalgebra as na;
use na::{DMatrix, Matrix2x3, RowVector3, Vector2};
fn main() {
// All the following matrices are equal but constructed in different ways.
let m = Matrix2x3::new(1.1, 1.2, 1.3, 2.1, 2.2, 2.3);
let m1 = Matrix2x3::from_rows(&[
RowVector3::new(1.1, 1.2, 1.3),
RowVector3::new(2.1, 2.2, 2.3),
]);
let m2 = Matrix2x3::from_columns(&[
Vector2::new(1.1, 2.1),
Vector2::new(1.2, 2.2),
Vector2::new(1.3, 2.3),
]);
let m3 = Matrix2x3::from_row_slice(&[1.1, 1.2, 1.3, 2.1, 2.2, 2.3]);
let m4 = Matrix2x3::from_column_slice(&[1.1, 2.1, 1.2, 2.2, 1.3, 2.3]);
let m5 = Matrix2x3::from_fn(|r, c| (r + 1) as f32 + (c + 1) as f32 / 10.0);
let m6 = Matrix2x3::from_iterator([1.1f32, 2.1, 1.2, 2.2, 1.3, 2.3].iter().cloned());
assert_eq!(m, m1);
assert_eq!(m, m2);
assert_eq!(m, m3);
assert_eq!(m, m4);
assert_eq!(m, m5);
assert_eq!(m, m6);
// All the following matrices are equal but constructed in different ways.
// This time, we used a dynamically-sized matrix to show the extra arguments
// for the matrix shape.
let dm = DMatrix::from_row_slice(
4,
3,
&[1.0, 0.0, 0.0, 0.0, 1.0, 0.0, 0.0, 0.0, 1.0, 0.0, 0.0, 0.0],
);
let dm1 = DMatrix::from_diagonal_element(4, 3, 1.0);
let dm2 = DMatrix::identity(4, 3);
let dm3 = DMatrix::from_fn(4, 3, |r, c| if r == c { 1.0 } else { 0.0 });
let dm4 = DMatrix::from_iterator(
4,
3,
[
// Components listed column-by-column.
1.0, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0,
]
.iter()
.cloned(),
);
assert_eq!(dm, dm1);
assert_eq!(dm, dm2);
assert_eq!(dm, dm3);
assert_eq!(dm, dm4);
}