Function accumulate_batch 

pub fn accumulate_batch(
    grid: GridView<'_>,
    peaks: PeakBatchView<'_>,
    support: SupportPolicy,
) -> Result<Accumulation, ProfileError>

Accumulate a borrowed peak batch and all derivatives on a validated grid.

Each peak is evaluated only at samples satisfying abs(x - position) <= support_fwhm * fwhm. Sparse derivative values are sample-major within each peak support and use the parameter order intensity, position, FWHM, and eta. The active sample set is held fixed when differentiating.

Errors

Returns ProfileError if support is invalid or allocation arithmetic overflows. Grid and peak validation occurs when their views are constructed.