quantrs2-ml 0.1.3

//! Memory systems for quantum continual learning

use crate::error::{MLError, Result};
use scirs2_core::ndarray::{Array1, Array2};
use super::config::{MemoryType, MemoryConfig};

/// Memory system trait
pub trait MemorySystem: std::fmt::Debug {
    fn store_examples(&mut self, data: &Array2<f64>, labels: &Array1<i32>) -> Result<()>;
    fn retrieve_examples(&self, n_examples: usize) -> Result<(Array2<f64>, Array1<i32>)>;
    fn get_statistics(&self) -> MemoryStatistics;
}

/// Memory statistics
#[derive(Debug, Clone)]
pub struct MemoryStatistics {
    pub capacity: usize,
    pub used: usize,
    pub efficiency: f64,
}

/// Episodic memory implementation
#[derive(Debug)]
pub struct EpisodicMemory {
    config: MemoryConfig,
    stored_data: Vec<Array1<f64>>,
    stored_labels: Vec<i32>,
}

impl EpisodicMemory {
    pub fn new(config: MemoryConfig) -> Self {
        Self {
            config,
            stored_data: Vec::new(),
            stored_labels: Vec::new(),
        }
    }
}

impl MemorySystem for EpisodicMemory {
    fn store_examples(&mut self, data: &Array2<f64>, labels: &Array1<i32>) -> Result<()> {
        for (i, row) in data.outer_iter().enumerate() {
            if self.stored_data.len() < self.config.capacity {
                self.stored_data.push(row.to_owned());
                self.stored_labels.push(labels[i]);
            }
        }
        Ok(())
    }

    fn retrieve_examples(&self, n_examples: usize) -> Result<(Array2<f64>, Array1<i32>)> {
        let n = n_examples.min(self.stored_data.len());
        if n == 0 {
            return Ok((Array2::zeros((0, 0)), Array1::zeros(0)));
        }

        let data = Array2::zeros((n, self.stored_data[0].len()));
        let labels = Array1::zeros(n);
        Ok((data, labels))
    }

    fn get_statistics(&self) -> MemoryStatistics {
        MemoryStatistics {
            capacity: self.config.capacity,
            used: self.stored_data.len(),
            efficiency: self.stored_data.len() as f64 / self.config.capacity as f64,
        }
    }
}

/// Create memory system based on type
pub fn create_memory_system(
    memory_type: MemoryType,
    config: MemoryConfig,
) -> Result<Box<dyn MemorySystem>> {
    match memory_type {
        MemoryType::Episodic => Ok(Box::new(EpisodicMemory::new(config))),
        MemoryType::Semantic => Ok(Box::new(EpisodicMemory::new(config))), // Placeholder
        MemoryType::Working => Ok(Box::new(EpisodicMemory::new(config))), // Placeholder
        MemoryType::Quantum => Ok(Box::new(EpisodicMemory::new(config))), // Placeholder
    }
}