scirs2-linalg 0.4.2

//! MPI Backend Configuration
//!
//! This module provides configuration and initialization for MPI backends,
//! including implementation-specific settings, performance tuning parameters,
//! and backend management.

use crate::error::{LinalgError, LinalgResult};
use super::{MPICommunicator, MPICollectiveOps, MPIPerformanceOptimizer, MPIFaultTolerance, MPITopologyManager, MPIMemoryManager};
use serde::{Deserialize, Serialize};
use std::collections::HashMap;
use std::sync::Arc;

/// MPI integration layer for distributed linear algebra
#[derive(Debug)]
pub struct MPIBackend {
    /// MPI configuration
    config: MPIConfig,
    /// MPI communicator wrapper
    communicator: MPICommunicator,
    /// Advanced collective operations
    collectives: MPICollectiveOps,
    /// Performance optimizer
    performance_optimizer: MPIPerformanceOptimizer,
    /// Fault tolerance manager
    fault_tolerance: MPIFaultTolerance,
    /// Topology manager
    topology_manager: MPITopologyManager,
    /// Memory manager for efficient data transfer
    memory_manager: MPIMemoryManager,
}

/// Configuration for MPI backend
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct MPIConfig {
    /// MPI implementation type
    pub implementation: MPIImplementation,
    /// Enable non-blocking communication
    pub non_blocking: bool,
    /// Use persistent communication requests
    pub persistent_requests: bool,
    /// Enable MPI-IO for distributed file operations
    pub enable_mpi_io: bool,
    /// Enable MPI-RMA (Remote Memory Access)
    pub enable_rma: bool,
    /// Buffer management strategy
    pub buffer_strategy: BufferStrategy,
    /// Collective algorithm hints
    pub collective_hints: CollectiveHints,
    /// Error handling strategy
    pub error_handling: MPIErrorHandling,
    /// Performance tuning parameters
    pub performance_tuning: MPIPerformanceTuning,
}

/// MPI implementation types
#[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize)]
pub enum MPIImplementation {
    /// Open MPI
    OpenMPI,
    /// Intel MPI
    IntelMPI,
    /// MPICH
    MPICH,
    /// Microsoft MPI
    MSMPI,
    /// IBM Spectrum MPI
    SpectrumMPI,
    /// MVAPICH
    MVAPICH,
    /// Custom implementation
    Custom(u32),
}

/// Buffer management strategies for MPI
#[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize)]
pub enum BufferStrategy {
    /// Automatic buffer management
    Automatic,
    /// User-managed buffers
    Manual,
    /// Pinned memory buffers
    Pinned,
    /// Registered memory regions
    Registered,
    /// Zero-copy buffers
    ZeroCopy,
}

/// Hints for collective operation optimization
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct CollectiveHints {
    /// Preferred algorithm for allreduce
    pub allreduce_algorithm: Option<String>,
    /// Preferred algorithm for allgather
    pub allgather_algorithm: Option<String>,
    /// Preferred algorithm for broadcast
    pub broadcast_algorithm: Option<String>,
    /// Enable pipelined operations
    pub enable_pipelining: bool,
    /// Chunk size for pipelined operations
    pub pipeline_chunksize: usize,
    /// Enable hierarchical operations
    pub enable_hierarchical: bool,
}

/// Error handling strategies for MPI
#[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize)]
pub enum MPIErrorHandling {
    /// Return error codes
    Return,
    /// Abort on errors
    Abort,
    /// Custom error handler
    Custom,
    /// Fault-tolerant mode
    FaultTolerant,
}

/// Performance tuning parameters
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct MPIPerformanceTuning {
    /// Eager protocol threshold
    pub eager_threshold: usize,
    /// Rendezvous protocol threshold
    pub rendezvous_threshold: usize,
    /// Maximum message segmentation size
    pub max_segmentsize: usize,
    /// Number of communication threads
    pub comm_threads: usize,
    /// Enable NUMA-aware binding
    pub numa_binding: bool,
    /// CPU affinity settings
    pub cpu_affinity: Vec<usize>,
    /// Memory alignment for performance
    pub memory_alignment: usize,
}

impl Default for MPIConfig {
    fn default() -> Self {
        Self {
            implementation: MPIImplementation::OpenMPI,
            non_blocking: true,
            persistent_requests: true,
            enable_mpi_io: true,
            enable_rma: false,
            buffer_strategy: BufferStrategy::Automatic,
            collective_hints: CollectiveHints {
                allreduce_algorithm: None,
                allgather_algorithm: None,
                broadcast_algorithm: None,
                enable_pipelining: true,
                pipeline_chunksize: 64 * 1024, // 64KB
                enable_hierarchical: true,
            },
            error_handling: MPIErrorHandling::FaultTolerant,
            performance_tuning: MPIPerformanceTuning {
                eager_threshold: 12 * 1024, // 12KB
                rendezvous_threshold: 64 * 1024, // 64KB
                max_segmentsize: 1024 * 1024, // 1MB
                comm_threads: 1,
                numa_binding: true,
                cpu_affinity: Vec::new(),
                memory_alignment: 64, // 64-byte alignment
            },
        }
    }
}

impl MPIBackend {
    /// Create a new MPI backend
    pub fn new(config: MPIConfig) -> LinalgResult<Self> {
        let communicator = MPICommunicator::new(&config)?;
        let collectives = MPICollectiveOps::new(Arc::new(communicator));

        // Initialize other components...
        // This is a simplified implementation - in practice would initialize all components

        Err(LinalgError::NotImplementedError(
            "Full MPI backend implementation pending".to_string()
        ))
    }

    /// Get the MPI configuration
    pub fn config(&self) -> &MPIConfig {
        &self.config
    }

    /// Get the communicator
    pub fn communicator(&self) -> &MPICommunicator {
        &self.communicator
    }

    /// Get the collective operations handler
    pub fn collectives(&self) -> &MPICollectiveOps {
        &self.collectives
    }

    /// Get the performance optimizer
    pub fn performance_optimizer(&self) -> &MPIPerformanceOptimizer {
        &self.performance_optimizer
    }

    /// Get the fault tolerance manager
    pub fn fault_tolerance(&self) -> &MPIFaultTolerance {
        &self.fault_tolerance
    }

    /// Get the topology manager
    pub fn topology_manager(&self) -> &MPITopologyManager {
        &self.topology_manager
    }

    /// Get the memory manager
    pub fn memory_manager(&self) -> &MPIMemoryManager {
        &self.memory_manager
    }
}