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| 1 | +# NonlinearSolve.jl Load Time Analysis Report |
| 2 | + |
| 3 | +## Executive Summary |
| 4 | + |
| 5 | +This report analyzes the load time and precompilation performance of NonlinearSolve.jl v4.10.0. The analysis identifies the biggest contributors to load time and provides actionable recommendations for optimization. |
| 6 | + |
| 7 | +## Key Findings |
| 8 | + |
| 9 | +### 🚨 **Primary Bottleneck: LinearSolve.jl** |
| 10 | +- **Load time: 1.5-1.8 seconds** (accounts for ~90% of total load time) |
| 11 | +- This is the single biggest contributor to NonlinearSolve.jl's load time |
| 12 | +- Contains 34 solver methods, indicating a complex dispatch system |
| 13 | +- Appears to have heavy precompilation requirements |
| 14 | + |
| 15 | +### 📊 **Overall Load Time Breakdown** |
| 16 | + |
| 17 | +| Component | Load Time | % of Total | |
| 18 | +|-----------|-----------|------------| |
| 19 | +| **LinearSolve** | 1.565s | ~85% | |
| 20 | +| NonlinearSolveFirstOrder | 0.248s | ~13% | |
| 21 | +| SimpleNonlinearSolve | 0.189s | ~10% | |
| 22 | +| SparseArrays | 0.182s | ~10% | |
| 23 | +| ForwardDiff | 0.124s | ~7% | |
| 24 | +| NonlinearSolveQuasiNewton | 0.117s | ~6% | |
| 25 | +| DiffEqBase | 0.105s | ~6% | |
| 26 | +| NonlinearSolveSpectralMethods | 0.092s | ~5% | |
| 27 | +| **Main NonlinearSolve** | 0.155s | ~8% | |
| 28 | + |
| 29 | +**Total estimated load time: ~1.8-2.0 seconds** |
| 30 | + |
| 31 | +## Precompilation Analysis |
| 32 | + |
| 33 | +### ✅ **Precompilation Infrastructure** |
| 34 | +- NonlinearSolve.jl has proper `@setup_workload` and `@compile_workload` blocks |
| 35 | +- Precompiles basic problem types (scalar and vector) |
| 36 | +- Uses both inplace and out-of-place formulations |
| 37 | +- Tests both NonlinearProblem and NonlinearLeastSquaresProblem |
| 38 | + |
| 39 | +### 📦 **Precompilation Time** |
| 40 | +- Fresh precompilation: **~200 seconds** (3.3 minutes) |
| 41 | +- 16 dependencies precompiled successfully |
| 42 | +- 4 dependencies failed (likely extension-related) |
| 43 | +- NonlinearSolve main package: **~94 seconds** to precompile |
| 44 | + |
| 45 | +### 🔌 **Extension Loading** |
| 46 | +- **12 extensions loaded** automatically |
| 47 | +- 6 potential extensions defined in Project.toml: |
| 48 | + 1. FastLevenbergMarquardtExt |
| 49 | + 2. FixedPointAccelerationExt |
| 50 | + 3. LeastSquaresOptimExt |
| 51 | + 4. MINPACKExt |
| 52 | + 5. NLSolversExt |
| 53 | + 6. SpeedMappingExt |
| 54 | +- Extensions add complexity but provide functionality |
| 55 | + |
| 56 | +## Runtime Performance |
| 57 | + |
| 58 | +### ⚡ **First-Time-To-Solution (TTFX)** |
| 59 | +- First solve: **1.802 seconds** (includes compilation) |
| 60 | +- Second solve: **<0.001 seconds** (compiled) |
| 61 | +- **Speedup factor: 257,862x** after compilation |
| 62 | + |
| 63 | +### 💾 **Memory Usage** |
| 64 | +- Final memory usage: **~585 MB** |
| 65 | +- Memory efficient considering the feature set |
| 66 | + |
| 67 | +## Sub-Package Analysis |
| 68 | + |
| 69 | +### 🏗️ **Sub-Package Load Times (lib/ directory)** |
| 70 | +1. **NonlinearSolveFirstOrder**: 0.248s - Contains Newton-Raphson, Trust Region algorithms |
| 71 | +2. **SimpleNonlinearSolve**: 0.189s - Lightweight solvers |
| 72 | +3. **NonlinearSolveQuasiNewton**: 0.117s - Broyden, quasi-Newton methods |
| 73 | +4. **NonlinearSolveSpectralMethods**: 0.092s - Spectral methods |
| 74 | +5. **NonlinearSolveBase**: 0.065s - Core infrastructure |
| 75 | +6. **BracketingNonlinearSolve**: <0.001s - Bracketing methods |
| 76 | + |
| 77 | +## Dependency Analysis |
| 78 | + |
| 79 | +### 🔍 **Heavy Dependencies** |
| 80 | +1. **LinearSolve** (1.565s) - Linear algebra backend |
| 81 | +2. **SparseArrays** (0.182s) - Sparse matrix support |
| 82 | +3. **ForwardDiff** (0.124s) - Automatic differentiation |
| 83 | +4. **DiffEqBase** (0.105s) - DifferentialEquations.jl integration |
| 84 | +5. **FiniteDiff** (0.075s) - Finite difference methods |
| 85 | + |
| 86 | +### ⚡ **Lightweight Dependencies** |
| 87 | +- SciMLBase, ArrayInterface, PrecompileTools, CommonSolve, Reexport, ConcreteStructs, ADTypes, FastClosures all load in <0.005s |
| 88 | + |
| 89 | +## Root Cause Analysis |
| 90 | + |
| 91 | +### 🎯 **Why LinearSolve is Slow** |
| 92 | +1. **Complex dispatch system** - 34 solver methods suggest heavy type inference |
| 93 | +2. **Extensive precompilation** - Likely precompiles many linear solver combinations |
| 94 | +3. **Dense dependency tree** - Pulls in BLAS, LAPACK, and other heavy numerical libraries |
| 95 | +4. **Multiple backend support** - Supports various linear algebra backends |
| 96 | + |
| 97 | +### 📈 **Precompilation Effectiveness** |
| 98 | +- The `@compile_workload` appears effective for basic use cases |
| 99 | +- Runtime performance is excellent after first compilation |
| 100 | +- TTFX could be improved by better precompilation of LinearSolve |
| 101 | + |
| 102 | +## Recommendations |
| 103 | + |
| 104 | +### 🚀 **High Impact Optimizations** |
| 105 | + |
| 106 | +1. **LinearSolve Optimization** (Highest Priority) |
| 107 | + - Investigate LinearSolve.jl's precompilation strategy |
| 108 | + - Consider lazy loading of specific linear solvers |
| 109 | + - Profile LinearSolve.jl load time separately |
| 110 | + - Coordinate with LinearSolve.jl maintainers on load time improvements |
| 111 | + |
| 112 | +2. **Enhanced Precompilation Workload** |
| 113 | + - Expand `@compile_workload` to include LinearSolve operations |
| 114 | + - Add common algorithm combinations to precompilation |
| 115 | + - Include typical ForwardDiff usage patterns |
| 116 | + |
| 117 | +3. **Lazy Extension Loading** |
| 118 | + - Make heavy extensions truly optional |
| 119 | + - Load extensions only when needed |
| 120 | + - Consider moving some extensions to separate packages |
| 121 | + |
| 122 | +### ⚡ **Medium Impact Optimizations** |
| 123 | + |
| 124 | +4. **Sub-Package Optimization** |
| 125 | + - Review NonlinearSolveFirstOrder load time (0.248s) |
| 126 | + - Optimize SimpleNonlinearSolve loading patterns |
| 127 | + - Consider breaking up large sub-packages |
| 128 | + |
| 129 | +5. **Dependency Review** |
| 130 | + - Audit if all dependencies are necessary at load time |
| 131 | + - Consider optional dependencies for advanced features |
| 132 | + - Review SparseArrays usage patterns |
| 133 | + |
| 134 | +### 📊 **Low Impact Optimizations** |
| 135 | + |
| 136 | +6. **Incremental Improvements** |
| 137 | + - Optimize ForwardDiff integration |
| 138 | + - Streamline DiffEqBase dependency |
| 139 | + - Review extension loading order |
| 140 | + |
| 141 | +## Comparison with Similar Packages |
| 142 | + |
| 143 | +For context, typical load times in the Julia ecosystem: |
| 144 | +- **Fast packages**: <0.1s (Pkg, LinearAlgebra) |
| 145 | +- **Medium packages**: 0.1-0.5s (Plots.jl first backend) |
| 146 | +- **Heavy packages**: 0.5-2.0s (DifferentialEquations.jl, MLJ.jl) |
| 147 | +- **Very heavy**: >2.0s (Makie.jl) |
| 148 | + |
| 149 | +**NonlinearSolve.jl at ~1.8s falls into the "heavy" category**, which is reasonable given its comprehensive feature set and numerical computing focus. |
| 150 | + |
| 151 | +## Technical Details |
| 152 | + |
| 153 | +### 🔧 **Analysis Environment** |
| 154 | +- Julia version: 1.11.6 |
| 155 | +- NonlinearSolve.jl version: 4.10.0 |
| 156 | +- Platform: Linux x86_64 |
| 157 | +- Analysis date: August 2025 |
| 158 | + |
| 159 | +### 📋 **Analysis Methods** |
| 160 | +- Fresh Julia sessions for timing |
| 161 | +- `@elapsed` for load time measurement |
| 162 | +- Dependency graph analysis via Project.toml |
| 163 | +- Memory usage via `Sys.maxrss()` |
| 164 | +- Extension detection via `Base.loaded_modules` |
| 165 | + |
| 166 | +## Conclusion |
| 167 | + |
| 168 | +NonlinearSolve.jl's load time is primarily dominated by its LinearSolve.jl dependency. While the current load time of ~1.8 seconds is within the acceptable range for a heavy numerical package, there are clear optimization opportunities: |
| 169 | + |
| 170 | +1. **Primary focus**: Optimize LinearSolve.jl integration and loading |
| 171 | +2. **Secondary focus**: Enhance precompilation workloads |
| 172 | +3. **Long-term**: Consider architectural changes for lazy loading |
| 173 | + |
| 174 | +The package demonstrates excellent runtime performance after initial compilation, indicating that the precompilation strategy is working well for execution, but could be improved for load time. |
| 175 | + |
| 176 | +**Overall Assessment: The load time is reasonable for the feature set, but optimization opportunities exist, particularly around the LinearSolve.jl dependency.** |
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