Struct TopN 

pub struct TopN(pub usize);

Retain the n terms of largest coefficient magnitude.

With t the n-th largest magnitude, every term above t is kept, plus as many terms at exactly t as fit in n, the first in bucket order; which tied terms survive is not a semantic promise. A sum of more than n terms keeps exactly n, and n == 0 clears; a NaN coefficient is never kept, so a sum with fewer than n other terms keeps those. Magnitudes are compared squared, so those below about 1.6e-162 tie at zero.

Tuple Fields

0: usize

The retained term count.

Trait Implementations

impl Clone for TopN

fn clone(&self) -> TopN

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for TopN

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl From<TopN> for BuiltinTruncation

fn from(p: TopN) -> Self

Converts to this type from the input type.

impl PartialEq for TopN

fn eq(&self, other: &TopN) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl<const W: usize> TruncationPolicy<W> for TopN

fn finalize_layer_partitioned( &self, local: &mut PauliSum<W>, collectives: &dyn Collectives, )

Panics above one partition, where the n-th largest of a split sum has no collective form yet.

fn finalize_layer(&self, sum: &mut PauliSum<W>)

Pass over the whole sum after each layer; PauliSum::retain is the easy way to write a filter here.

fn keep_term(&self, _x: &[u64; W], _z: &[u64; W], _c: Complex64) -> bool

Per-term filter, run inside the merge on every output, so it must be cheap.

fn finalizes_layer(&self) -> bool

Whether finalize_layer does anything, a hint that lets the engine skip it.

fn supports_partitioned(&self) -> bool

Whether finalize_layer_partitioned runs above one partition; every partitioned driver checks it before the first layer.

impl Copy for TopN

impl StructuralPartialEq for TopN