LLMMCTS/examples/configuration_examples.jl

# MCTS Configuration Examples

This file demonstrates different MCTS configuration options and their effects on search behavior.

```julia
using LLMMCTS

# Simple transition function for demonstration
function simple_transition(state::Dict, args::NamedTuple)
    current_step = get(state, :step, 0)
    newstate = Dict(
        :step => current_step + 1,
        :reward => (current_step + 1) * 2,
        :isterminal => current_step >= args.max_steps - 1
    )
    progressvalue = (current_step / args.max_steps) * 10
    return Dict(
        :newNodeKey => "step_$current_step",
        :newstate => newstate,
        :progressvalue => progressvalue
    )
end

initialstate = Dict(
    :step => 0,
    :reward => 0,
    :isterminal => false
)

transitionargs = (max_steps = 5,)

# ============================================================================
# Example 1: Balanced Search (Default)
# ============================================================================
println("Example 1: Balanced Search (Default)")
println("=" ^ 50)

result1 = runMCTS(
    initialstate,
    simple_transition,
    transitionargs;
    maxiterations = 10,
    explorationweight = 1.0,  # Balanced exploration/exploitation
    maxSimulationDepth = 3,
    horizontalSampleExpansionPhase = 3
)

println("Exploration weight: 1.0 (balanced)")
println("Root visits: ", result1.root.visits)
println("Best terminal step: ", result1.bestTerminalState[:step])
println()

# ============================================================================
# Example 2: Aggressive Exploration
# ============================================================================
println("Example 2: Aggressive Exploration")
println("=" * 50)

result2 = runMCTS(
    initialstate,
    simple_transition,
    transitionargs;
    maxiterations = 10,
    explorationweight = 2.0,  # More exploration
    maxSimulationDepth = 3,
    horizontalSampleExpansionPhase = 5  # More children per node
)

println("Exploration weight: 2.0 (aggressive exploration)")
println("Root visits: ", result2.root.visits)
println("Children explored: ", length(result2.root.children))
println()

# ============================================================================
# Example 3: Deep Search (Long Horizon)
# ============================================================================
println("Example 3: Deep Search (Long Horizon)")
println("=" * 50)

result3 = runMCTS(
    initialstate,
    simple_transition,
    transitionargs;
    maxiterations = 20,
    explorationweight = 1.0,
    maxSimulationDepth = 5,  # Deeper search
    horizontalSampleExpansionPhase = 3
)

println("Max simulation depth: 5 (deep search)")
println("Root visits: ", result3.root.visits)
println("Search explores further into the future")
println()

# ============================================================================
# Example 4: Fast Search (Shallow, Many Iterations)
# ============================================================================
println("Example 4: Fast Search (Shallow, Many Iterations)")
println("=" * 50)

result4 = runMCTS(
    initialstate,
    simple_transition,
    transitionargs;
    maxiterations = 50,  # Many iterations
    explorationweight = 1.0,
    maxSimulationDepth = 2,  # Shallow search
    horizontalSampleExpansionPhase = 3
)

println("Many iterations (50), shallow depth (2)")
println("Root visits: ", result4.root.visits)
println("Faster but less thorough search")
println()

# ============================================================================
# Example 5: Parallel Simulation (Multithreading)
# ============================================================================
println("Example 5: Parallel Simulation (Multithreading)")
println("=" * 50)

result5 = runMCTS(
    initialstate,
    simple_transition,
    transitionargs;
    maxiterations = 10,
    explorationweight = 1.0,
    maxSimulationDepth = 3,
    horizontalSampleExpansionPhase = 3,
    multithread = true  # Enable parallel simulation
)

println("Multithreading enabled")
println("Root visits: ", result5.root.visits)
println("Parallel simulation across child nodes")
println()

# ============================================================================
# Example 6: Early Stopping
# ============================================================================
println("Example 6: Early Stopping")
println("=" * 50)

# Define early stopping function
function early_stop(state::Dict)
    # Stop when we reach a good enough solution
    return get(state, :step, 0) >= 3
end

result6 = runMCTS(
    initialstate,
    simple_transition,
    transitionargs;
    maxiterations = 20,  # Would run more if not for early stop
    explorationweight = 1.0,
    maxSimulationDepth = 3,
    horizontalSampleExpansionPhase = 3,
    earlystop = early_stop
)

println("Early stopping enabled (stops at step >= 3)")
println("Actual iterations: ", result6.root.visits)
println("Early stopping saved unnecessary computation")
println()

# ============================================================================
# Example 7: Save Simulation Nodes (for Analysis)
# ============================================================================
println("Example 7: Save Simulation Nodes")
println("=" * 50)

result7 = runMCTS(
    initialstate,
    simple_transition,
    transitionargs;
    maxiterations = 5,
    explorationweight = 1.0,
    maxSimulationDepth = 3,
    horizontalSampleExpansionPhase = 3,
    saveSimulatedNode = true  # Keep simulation nodes
)

println("saveSimulatedNode = true")
println("Simulation nodes are preserved")
println("Root children: ", length(result7.root.children))
println("Useful for debugging or further analysis")
println()

# ============================================================================
# Example 8: High-Value State Tracking
# ============================================================================
println("Example 8: High-Value State Tracking")
println("=" * 50)

# Transition that can produce high-value states
function high_value_transition(state::Dict, args::NamedTuple)
    current_step = get(state, :step, 0)
    reward = current_step * 3
    
    # Occasionally produce high-value states
    if current_step == 2 || current_step == 4
        reward = 9.0  # High value
    end
    
    newstate = Dict(
        :step => current_step + 1,
        :reward => reward,
        :isterminal => current_step >= args.max_steps - 1
    )
    progressvalue = (current_step / args.max_steps) * 10
    return Dict(
        :newNodeKey => "step_$current_step",
        :newstate => newstate,
        :progressvalue => progressvalue
    )
end

high_value_initial = Dict(
    :step => 0,
    :reward => 0,
    :isterminal => false
)

result8 = runMCTS(
    high_value_initial,
    high_value_transition,
    transitionargs;
    maxiterations = 15,
    explorationweight = 1.0,
    maxSimulationDepth = 3,
    horizontalSampleExpansionPhase = 3
)

println("High-value states found: ", length(result8.highValueStateList))
println("States with reward >= 8 were tracked")
for (i, state) in enumerate(result8.highValueStateList)
    println("  High-value state $i: step = ", state[:step])
end
```