Struct Accumulator 

pub struct Accumulator<const N_BLOCKS: usize = 1024, const INIT_BLOCK_DEPTH: u64 = 16> { /* private fields */ }

A structure for computing statistics using the blocking method.

The blocking method reduces the effects of autocorrelation in Monte Carlo simulations by grouping consecutive measurements into blocks. Each block stores the sum of its values and their squares, enabling the computation of mean, variance, error of the mean, and autocorrelation time.

Generics

• N_BLOCKS: Number of blocks to use (must be a power of 2).
• INIT_BLOCK_DEPTH: Initial depth of each block (number of measurements per block).

Methods

• add: Adds a measurement to the accumulator.
• statistics: Computes mean, error, autocorrelation time, and variance.
• clear: Resets the accumulator to its initial state.

Implementations

impl<const N_BLOCKS: usize, const INIT_BLOCK_DEPTH: u64> Accumulator<N_BLOCKS, INIT_BLOCK_DEPTH>

pub fn new() -> Self

Creates a new Accumulator instance.

Panics

Panics if N_BLOCKS is not a power of 2.

pub fn size(&self) -> u64

Returns the total number of input values added to the accumulator.

pub fn add(&mut self, val: f64)

Adds a new measurement to the accumulator.

If the current block is full, it moves to the next block. When all blocks are filled, the block depth is doubled, and the data is consolidated into fewer, larger blocks.

pub fn statistics(&self) -> Option<(f64, f64, f64, f64)>

Computes and returns the mean, error of the mean, autocorrelation time, and standard deviation.

Returns None if no measurements have been added.

Returns

A tuple containing:

• mean: The mean of the measurements.
• mean_error: The error of the mean, accounting for autocorrelation.
• autocorr_time: The estimated autocorrelation time.
• std_dev: The square root of the variance (standard deviation).

pub fn clear(&mut self)

Resets the accumulator, clearing all measurements and restoring initial settings.

Trait Implementations

impl<const N_BLOCKS: usize, const INIT_BLOCK_DEPTH: u64> Default for Accumulator<N_BLOCKS, INIT_BLOCK_DEPTH>

fn default() -> Self

Default implementation for Accumulator<N_BLOCKS, INIT_BLOCK_DEPTH>