tracel-ai/burn · error

window size must be non-zero

Error message

window size must be non-zero

What it means

Dataset::windows(size) converts the requested window size into a NonZeroUsize and panics when size is 0, because zero-sized overlapping windows are mathematically undefined. The library enforces this eagerly at iterator construction rather than producing an empty iterator.

Source

Thrown at crates/burn-dataset/src/transform/window.rs:56

    /// Panics if `size` is 0.    
    ///
    /// # Examples
    ///
    /// ```
    /// use crate::burn_dataset::{
    ///    transform::{Windows, WindowsDataset},
    ///    Dataset, InMemDataset,
    /// };
    ///
    /// let items = [1, 2, 3, 4].to_vec();
    /// let dataset = InMemDataset::new(items.clone());
    ///
    /// for window in dataset.windows(2) {
    ///  // window is a Result<Vec<I>, DatasetError>
    /// }
    /// ```
    fn windows(&self, size: usize) -> WindowsIterator<'_, I> {
        let size = NonZeroUsize::new(size).expect("window size must be non-zero");
        WindowsIterator::new(self, size)
    }
}

/// Overlapping windows iterator.
pub struct WindowsIterator<'a, I> {
    /// The size of the windows.
    pub size: NonZeroUsize,
    current: usize,
    len: usize,
    dataset: &'a dyn Dataset<I>,
}

impl<'a, I> WindowsIterator<'a, I> {
    /// Creates a new `WindowsIterator` instance. The windows overlap.
    /// Is empty if the input `Dataset` is shorter than `size`.
    ///
    /// # Parameters

View on GitHub (pinned to d16f7ba2ed)

Solutions

1. Pass a window size >= 1; clamp with size.max(1) if the value is dynamic.
2. Validate configuration before constructing the dataset.
3. Use NonZeroUsize in your own config type so 0 is unrepresentable.

Example fix

// before
let windows = dataset.windows(config.window_size);
// after
assert!(config.window_size > 0, "window_size must be > 0");
let windows = dataset.windows(config.window_size.max(1));

fn safe_windows<'a, I: Clone>(ds: &'a dyn Dataset<I>, size: usize) -> WindowsIterator<'a, I> {
    assert!(size >= 1, "window size must be >= 1, got {size}");
    ds.windows(size)
}

fn is_valid_window_size(size: usize) -> bool { size > 0 }

When it happens

Trigger: Calling dataset.windows(0) on any implementor of the Dataset trait.

Common situations: Window size read from CLI/config defaulting to 0 before a value is set; computing size as len - k where k >= len; off-by-one in parameter parsing.

Related errors

• Name is not set
• capture tensor operations must run inside CaptureDevice::cap
• Index out of bounds for InMemDataset: {index} >= {}
• The database file does not exist
• Index out of bounds for ComposedDataset: {index} >= {}

AI-assisted analysis of tracel-ai/burn@d16f7ba2ed (2026-09-05). Data as JSON: /api/errors/640dd5a49b70c994. Report an issue: GitHub.