[−][src]Module ndarray::doc::ndarray_for_numpy_users::simple_math

Example of simple math operations on 2-D arrays.

NumPy

ndarray

import numpy as np




a = np.full((5, 4), 3.)


a[::2, :] = 2.


a[:, 1] = np.sin(a[:, 1]) + 1.


a[a < 1.5] = 4.


odd_sum = a[:, 1::2].sum()


b = np.exp(np.arange(4))


c = a + b


d = c.T.dot(a)

extern crate ndarray;

use ndarray::prelude::*;

// Create a 5×4 array of threes.
let mut a = Array2::<f64>::from_elem((5, 4), 3.);

// Fill the even-index rows with twos.
a.slice_mut(s![..;2, ..]).fill(2.);

// Change column 1 to sin(x) + 1.
a.column_mut(1).mapv_inplace(|x| x.sin() + 1.);

// Change values less than 1.5 to 4.
a.mapv_inplace(|x| if x < 1.5 { 4. } else { x });

// Compute the sum of the odd-index columns.
let odd_sum = a.slice(s![.., 1..;2]).sum();

// Create a 1-D array of exp(index).
let b = Array::from_shape_fn(4, |i| (i as f64).exp());

// Add b to a (broadcasting to rows).
let c = a + &b;

// Matrix product of c transpose with c.
let d = c.t().dot(&c);