candle/candle-nn/tests/loss.rs

use candle::{Device, Result, Tensor};

/* Equivalent python code:
import torch
import torch.nn.functional as F
input = torch.tensor([
    [ 1.1050,  0.3013, -1.5394, -2.1528, -0.8634],
    [ 1.0730, -0.9419, -0.1670, -0.6582,  0.5061],
    [ 0.8318,  1.1154, -0.3610,  0.5351,  1.0830]])

target = torch.tensor([1, 0, 4])
print(F.nll_loss(F.log_softmax(input, dim=1), target))
print(F.cross_entropy(input, target))
*/
#[test]
fn nll_and_cross_entropy() -> Result<()> {
    let cpu = Device::Cpu;
    let input = Tensor::new(
        &[
            [1.1050f32, 0.3013, -1.5394, -2.1528, -0.8634],
            [1.0730, -0.9419, -0.1670, -0.6582, 0.5061],
            [0.8318, 1.1154, -0.3610, 0.5351, 1.0830],
        ],
        &cpu,
    )?;
    let target = Tensor::new(&[1u32, 0, 4], &cpu)?;

    let log_softmax = candle_nn::ops::log_softmax(&input, 1)?;
    let loss = candle_nn::loss::nll(&log_softmax, &target)?;
    assert_eq!(loss.to_vec0::<f32>()?, 1.1312335);
    let loss = candle_nn::loss::cross_entropy(&input, &target)?;
    assert_eq!(loss.to_vec0::<f32>()?, 1.1312335);
    Ok(())
}