pub fn mean_where<T, D>(
a: &Array<T, D>,
axis: Option<usize>,
where_mask: Option<&Array<bool, IxDyn>>,
) -> Result<Array<T, IxDyn>, FerrayError>Expand description
Mean reduction with a where mask.
Equivalent to np.mean(a, axis=axis, where=where_mask). The divisor
is the count of true positions in the (broadcast) mask, NOT the
lane length — fully-masked-out lanes return T::nan() (matching
NumPy’s “RuntimeWarning: Mean of empty slice” behavior, but without
the warning machinery). initial is intentionally not modeled
because the divisor for an “initial-bumped” mean is ambiguous in
NumPy too. where_mask is broadcast-compatible with a.shape()
(#565).