Function callable_filter 

#[unsafe(no_mangle)]
pub unsafe extern "C" fn callable_filter(
    buffer: *const f64,
    filter_size: usize,
    return_value: *mut f64,
    q: *mut CompilerResult,
) -> i64

Interface for Sympy’s LowLevelCallable (image filtering).

Safety

1. If the model cannot be compiled to a fast function, NULL is returned.
2. The resulting function lives as long as q does and should not be stored
    separately.