//! Second-order stochastic optimization algorithms.
//!
//! This module provides second-order quasi-Newton methods suitable for both
//! deterministic and stochastic optimization:
//!
//! - **L-BFGS-B** (`lbfgsb`): Limited-memory BFGS with box constraints,
//! featuring strong Wolfe line search and Cauchy-point computation.
//! - **SR1** (`sr1`): Symmetric rank-1 quasi-Newton with trust-region
//! globalization and limited-memory compact representation.
//! - **S-L-BFGS** (`slbfgs`): Stochastic L-BFGS combining mini-batch
//! gradients, curvature pairs from large batches, and optional SVRG
//! variance reduction.
//!
//! ## References
//!
//! - Byrd et al. (1995). "A limited memory algorithm for bound constrained
//! optimization." SIAM J. Sci. Comput.
//! - Byrd, Khalfan & Schnabel (1994). "Analysis of a symmetric rank-one
//! trust region method." SIAM J. Optim.
//! - Moritz, Nishihara & Jordan (2016). "A linearly-convergent stochastic
//! L-BFGS algorithm." AISTATS.
// Re-exports for convenient access
pub use ;
pub use ;
pub use ;
pub use ;