|
| 1 | +# Integration Methods Overview |
| 2 | + |
| 3 | +SymbolicIntegration.jl uses a flexible method dispatch system that allows you to choose different integration algorithms based on your needs. |
| 4 | + |
| 5 | +## Available Methods |
| 6 | + |
| 7 | +### RischMethod (Default) |
| 8 | + |
| 9 | +The **Risch method** is the complete algorithm for symbolic integration of elementary functions, based on Manuel Bronstein's algorithms. |
| 10 | + |
| 11 | +```julia |
| 12 | +# Default usage |
| 13 | +integrate(f, x) # Automatically uses RischMethod |
| 14 | + |
| 15 | +# Explicit usage |
| 16 | +integrate(f, x, RischMethod()) |
| 17 | + |
| 18 | +# With configuration |
| 19 | +integrate(f, x, RischMethod(use_algebraic_closure=true, catch_errors=false)) |
| 20 | +``` |
| 21 | + |
| 22 | +**Capabilities:** |
| 23 | +- β
Rational functions with exact arctangent terms |
| 24 | +- β
Exponential and logarithmic functions |
| 25 | +- β
Trigonometric functions (via transformation) |
| 26 | +- β
Complex root handling |
| 27 | +- β
Integration by parts |
| 28 | + |
| 29 | +**Best for:** Complete symbolic integration with guaranteed correctness |
| 30 | + |
| 31 | +[β See detailed Risch documentation](risch.md) |
| 32 | + |
| 33 | +## Future Methods |
| 34 | + |
| 35 | +The method dispatch system is designed to support additional integration algorithms: |
| 36 | + |
| 37 | +### Planned Methods |
| 38 | + |
| 39 | +#### HeuristicMethod (Future) |
| 40 | +Fast pattern-matching based integration for common cases. |
| 41 | +```julia |
| 42 | +integrate(f, x, HeuristicMethod()) # Fast heuristic patterns |
| 43 | +``` |
| 44 | + |
| 45 | +#### NumericalMethod (Future) |
| 46 | +Numerical integration with symbolic preprocessing. |
| 47 | +```julia |
| 48 | +integrate(f, x, NumericalMethod(tolerance=1e-10)) # Numerical fallback |
| 49 | +``` |
| 50 | + |
| 51 | +#### SymPyMethod (Future) |
| 52 | +Integration using SymPy backend for comparison. |
| 53 | +```julia |
| 54 | +integrate(f, x, SymPyMethod()) # SymPy compatibility |
| 55 | +``` |
| 56 | + |
| 57 | +## Method Selection Guide |
| 58 | + |
| 59 | +### Choosing the Right Method |
| 60 | + |
| 61 | +| Use Case | Recommended Method | Reason | |
| 62 | +|----------|-------------------|---------| |
| 63 | +| **Exact symbolic results** | `RischMethod()` | Complete, guaranteed correct | |
| 64 | +| **Research/verification** | `RischMethod(catch_errors=false)` | Strict algorithmic behavior | |
| 65 | +| **Production applications** | `RischMethod(catch_errors=true)` | Robust error handling | |
| 66 | +| **Complex analysis** | `RischMethod(use_algebraic_closure=true)` | Full arctangent terms | |
| 67 | +| **Simple computations** | `RischMethod(use_algebraic_closure=false)` | Faster execution | |
| 68 | + |
| 69 | +### Method Comparison |
| 70 | + |
| 71 | +| Method | Speed | Completeness | Robustness | Use Case | |
| 72 | +|--------|-------|--------------|------------|----------| |
| 73 | +| **RischMethod** | Moderate | Complete | High | Research, exact results | |
| 74 | +| **HeuristicMethod** (future) | Fast | Partial | Moderate | Common patterns | |
| 75 | +| **NumericalMethod** (future) | Variable | Approximate | High | Fallback cases | |
| 76 | + |
| 77 | +## Method Architecture |
| 78 | + |
| 79 | +### Abstract Type Hierarchy |
| 80 | +```julia |
| 81 | +AbstractIntegrationMethod |
| 82 | +βββ RischMethod # Complete symbolic integration |
| 83 | +βββ AbstractRationalIntegration # Rational function specialists |
| 84 | +βββ AbstractTranscendentalIntegration # Transcendental specialists |
| 85 | +``` |
| 86 | + |
| 87 | +### Method Interface |
| 88 | +```julia |
| 89 | +# General interface |
| 90 | +integrate(f, x, method::AbstractIntegrationMethod; kwargs...) |
| 91 | + |
| 92 | +# Method-specific traits |
| 93 | +method_supports_rational(method) # Check rational function support |
| 94 | +method_supports_transcendental(method) # Check transcendental support |
| 95 | +``` |
| 96 | + |
| 97 | +## Configuration Patterns |
| 98 | + |
| 99 | +### Common Configurations |
| 100 | + |
| 101 | +```julia |
| 102 | +# Research configuration (strict, complete) |
| 103 | +research_config = RischMethod( |
| 104 | + use_algebraic_closure=true, |
| 105 | + catch_errors=false |
| 106 | +) |
| 107 | + |
| 108 | +# Production configuration (robust, complete) |
| 109 | +production_config = RischMethod( |
| 110 | + use_algebraic_closure=true, |
| 111 | + catch_errors=true |
| 112 | +) |
| 113 | + |
| 114 | +# Performance configuration (fast, simple) |
| 115 | +performance_config = RischMethod( |
| 116 | + use_algebraic_closure=false, |
| 117 | + catch_errors=true |
| 118 | +) |
| 119 | +``` |
| 120 | + |
| 121 | +### Method Workflows |
| 122 | + |
| 123 | +```julia |
| 124 | +@variables x f |
| 125 | + |
| 126 | +# Try different methods in sequence |
| 127 | +function robust_integrate(f, x) |
| 128 | + try |
| 129 | + # First try exact Risch method |
| 130 | + return integrate(f, x, RischMethod(catch_errors=false)) |
| 131 | + catch NotImplementedError |
| 132 | + # Fall back to heuristic method (future) |
| 133 | + return integrate(f, x, HeuristicMethod()) |
| 134 | + catch AlgorithmFailedError |
| 135 | + # Fall back to numerical method (future) |
| 136 | + return integrate(f, x, NumericalMethod()) |
| 137 | + end |
| 138 | +end |
| 139 | +``` |
| 140 | + |
| 141 | +## Extending with New Methods |
| 142 | + |
| 143 | +The method system is designed for easy extension: |
| 144 | + |
| 145 | +### Adding a New Method |
| 146 | + |
| 147 | +1. **Define method type**: |
| 148 | +```julia |
| 149 | +struct MyMethod <: AbstractIntegrationMethod |
| 150 | + option1::Bool |
| 151 | + option2::Float64 |
| 152 | +end |
| 153 | +``` |
| 154 | + |
| 155 | +2. **Implement integration**: |
| 156 | +```julia |
| 157 | +function SymbolicIntegration._integrate(f, x, method::MyMethod; kwargs...) |
| 158 | + # Your algorithm implementation |
| 159 | + return result |
| 160 | +end |
| 161 | +``` |
| 162 | + |
| 163 | +3. **Add method traits**: |
| 164 | +```julia |
| 165 | +method_supports_rational(method::MyMethod) = true |
| 166 | +method_supports_transcendental(method::MyMethod) = false |
| 167 | +``` |
| 168 | + |
| 169 | +### Plugin Architecture |
| 170 | + |
| 171 | +The dispatch system supports: |
| 172 | +- **Third-party packages**: Can add new methods |
| 173 | +- **Method composition**: Combining different approaches |
| 174 | +- **Fallback chains**: Trying multiple methods in sequence |
| 175 | +- **Performance optimization**: Method-specific tuning |
| 176 | + |
| 177 | +## Performance and Benchmarking |
| 178 | + |
| 179 | +### Method Performance Characteristics |
| 180 | + |
| 181 | +- **RischMethod**: Exact results, moderate speed, complete coverage |
| 182 | +- **Future methods**: Will provide different speed/accuracy tradeoffs |
| 183 | + |
| 184 | +### Benchmarking Methods |
| 185 | + |
| 186 | +```julia |
| 187 | +using BenchmarkTools |
| 188 | + |
| 189 | +@variables x |
| 190 | +f = (x^3 + x^2 + x + 2)/(x^4 + 3*x^2 + 2) |
| 191 | + |
| 192 | +# Benchmark different configurations |
| 193 | +@benchmark integrate($f, $x, RischMethod(use_algebraic_closure=true)) |
| 194 | +@benchmark integrate($f, $x, RischMethod(use_algebraic_closure=false)) |
| 195 | +``` |
| 196 | + |
| 197 | +## Migration and Compatibility |
| 198 | + |
| 199 | +### Current Usage Patterns |
| 200 | + |
| 201 | +All existing code continues to work: |
| 202 | +```julia |
| 203 | +# Existing code (still works) |
| 204 | +integrate(f, x) |
| 205 | + |
| 206 | +# New explicit method (equivalent) |
| 207 | +integrate(f, x, RischMethod()) |
| 208 | +``` |
| 209 | + |
| 210 | +The method system provides a **migration path** for users to gradually adopt new integration methods as they become available, while maintaining full compatibility with existing workflows. |
0 commit comments