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[Major Rewrite] 600K->71K LOC Backend Rewrite, dynamic IL emission and kernel inlining, SIMD parallelism, 25 new np.* and more#573

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[Major Rewrite] 600K->71K LOC Backend Rewrite, dynamic IL emission and kernel inlining, SIMD parallelism, 25 new np.* and more#573
Nucs wants to merge 106 commits intomasterfrom
ilkernel

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@Nucs Nucs commented Feb 15, 2026

Summary

This PR implements the IL Kernel Generator, replacing NumSharp's ~500K+ lines of template-generated type-switch code with ~7K lines of dynamic IL emission using System.Reflection.Emit.

Closes #544 - [Core] Replace ~636K lines of generated math code with DynamicMethod IL emission
Closes #545 - [Core] SIMD-Optimized IL Emission (SIMD for contiguous arrays AND scalar broadcast)

Changes

Core Kernel Infrastructure (~7K lines)

File Lines Purpose
ILKernelGenerator.cs 4,800+ Main IL emission engine with SIMD support
SimdKernels.cs 626 SIMD vector operations (Vector256)
ReductionKernel.cs 377 Reduction operation definitions
BinaryKernel.cs 284 Binary operation enums & delegates

Dispatch Files

  • DefaultEngine.BinaryOp.cs - Binary ops (Add, Sub, Mul, Div, Mod)
  • DefaultEngine.UnaryOp.cs - 22 unary ops (Sin, Cos, Sqrt, Exp, etc.)
  • DefaultEngine.CompareOp.cs - Comparisons (==, !=, <, >, <=, >=)
  • DefaultEngine.BitwiseOp.cs - Bitwise AND/OR/XOR
  • DefaultEngine.ReductionOp.cs - Element-wise reductions

Files Deleted (73 total)

  • 60 type-specific binary op files (Add, Sub, Mul, Div, Mod × 12 types)
  • 13 type-specific comparison files (Equals × 12 types + dispatcher)

Net change: -498,481 lines (13,553 additions, 512,034 deletions)

SIMD Optimizations

Execution Path SIMD Status

Path Description IL SIMD C# SIMD Fallback
SimdFull Both arrays contiguous, same type ✅ Yes ✅ Yes
SimdScalarRight Array + scalar (LHS type == Result type) ✅ Yes ✅ Yes
SimdScalarLeft Scalar + array (RHS type == Result type) ✅ Yes ✅ Yes
SimdChunk Inner-contiguous broadcast ❌ No (TODO) ✅ Yes (same-type)
General Arbitrary strides ❌ No ❌ No

Note: Same-type operations (e.g., double + double) fall back to C# SimdKernels.cs which has full SIMD for SimdFull, SimdScalarRight/Left, and SimdChunk paths.

Scalar Broadcast Optimization

SIMD scalar operations hoist Vector256.Create(scalar) outside the loop:

// Before: scalar loop
for (int i = 0; i < n; i++)
    result[i] = lhs[i] + scalar;

// After: SIMD with hoisted broadcast
var scalarVec = Vector256.Create(scalar);  // hoisted!
for (; i <= n - 4; i += 4)
    (Vector256.Load(lhs + i) + scalarVec).Store(result + i);

Benchmark (10M elements):

Operation Time
double + double_scalar 15.29 ms (baseline)
double + int_scalar 14.96 ms (IL SIMD ✓)
float + int_scalar 7.18 ms (IL SIMD ✓)

Bug Fixes Included

  1. operator & and operator | - Were completely broken (returned null)
  2. Log1p - Incorrectly using Log10 instead of Log
  3. Sliced array × scalar - Incorrectly used SIMD path causing wrong indexing
  4. Division type promotion - int/int now returns float64 (NumPy 2.x behavior)
  5. Sign(NaN) - Now returns NaN instead of throwing ArithmeticException

Test Plan

  • All 2,597 tests pass (excluding OpenBugs category)
  • New test files: BattleProofTests, BinaryOpTests, UnaryOpTests, ComparisonOpTests, ReductionOpTests
  • Edge cases: NaN handling, empty arrays, sliced arrays, broadcast shapes, all 12 dtypes
  • SIMD correctness: verified with arrays of various sizes (including non-vector-aligned)

Architecture

Backends/Kernels/
├── ILKernelGenerator.cs    # IL emission engine with SIMD
├── BinaryKernel.cs         # Binary/Unary operation definitions
├── ReductionKernel.cs      # Reduction operation definitions
├── ScalarKernel.cs         # Scalar operation keys
├── SimdKernels.cs          # SIMD Vector256 operations (C# fallback)
└── KernelCache.cs          # Thread-safe kernel caching

Backends/Default/Math/
├── DefaultEngine.BinaryOp.cs
├── DefaultEngine.UnaryOp.cs
├── DefaultEngine.CompareOp.cs
├── DefaultEngine.BitwiseOp.cs
└── DefaultEngine.ReductionOp.cs

Performance

  • SIMD vectorization for contiguous arrays (Vector256) - all numeric types
  • SIMD scalar broadcast for mixed-type scalar operations (when array type == result type)
  • Strided path for sliced/broadcast arrays via coordinate iteration
  • Type promotion following NumPy 2.x semantics
  • Kernels are cached by (operation, input types, output type)

Future Work

  • IL SIMD for SimdChunk path (inner-contiguous broadcast)
  • AVX-512 / Vector512 support (when hardware adoption increases)
  • Vectorized type conversion for int + double_scalar cases

Additional: NativeMemory Modernization

Closes #528 - Modernize unmanaged allocation: Marshal.AllocHGlobal → NativeMemory

Replaced deprecated Marshal.AllocHGlobal/FreeHGlobal with modern .NET 6+ NativeMemory.Alloc/Free API across 5 allocation sites. Benchmarks confirmed identical performance.

@Nucs Nucs added this to the NumPy 2.x Compliance milestone Feb 15, 2026
@Nucs Nucs added bug Something isn't working core Internal engine: Shape, Storage, TensorEngine, iterators refactor Code cleanup without behavior change labels Feb 15, 2026
@Nucs Nucs self-assigned this Feb 15, 2026
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Nucs commented Feb 21, 2026

Additional: NativeMemory Modernization (#528)

This PR now also includes the NativeMemory allocation modernization (commit c8ddfd6):

  • Replaced Marshal.AllocHGlobal/FreeHGlobal with NativeMemory.Alloc/Free
  • 5 allocation sites updated across 2 files
  • Benchmarks confirmed identical performance

Closes #528

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Nucs commented Mar 11, 2026

Leftover: Regen Templates That Could Become IL-Generated

Analysis of remaining hard-coded switch cases (~82K lines) that could be migrated to ILKernelGenerator:

High Priority: Axis Reductions (~45K lines)

The Default.Reduction.*.cs files have element-wise IL kernels but still use Regen-templated 12×12 type switches for axis-based iteration:

File Lines Pattern
Default.Reduction.Std.cs 11,070 Nested switch (input × output type)
Default.Reduction.Var.cs 9,315 Nested switch
Default.Reduction.CumAdd.cs 4,493 Nested switch
Default.Reduction.Mean.cs 4,248 Nested switch
Default.Reduction.Product.cs 4,136 Nested switch
Default.Reduction.Add.cs 4,120 Nested switch
Default.Reduction.AMin.cs 3,599 Nested switch
Default.Reduction.AMax.cs 3,599 Nested switch
Default.Reduction.ArgMax.cs 815 Single switch
Default.Reduction.ArgMin.cs 855 Single switch

High Impact: BLAS Operations (~36K lines)

Triple-nested switches (result × left × right = 1,728 type combinations):

File Lines Notes
Default.MatMul.2D2D.cs 19,924 Consider BLAS integration
Default.Dot.NDMD.cs 15,880 Consider BLAS integration

Medium Priority: Other Operations

File Lines Notes
Default.Shift.cs ~200 LeftShift/RightShift (enum defined but not IL)
Default.ClipNDArray.cs ~600 NDArray bounds clipping
Default.ATan2.cs ~500 Two-argument arctangent
Default.Power.cs ~500 Scalar exponent path

Reduction Ops Pending (defined in KernelOp.cs as Future)

  • Std, Var - two-pass algorithms
  • NanSum, NanProd, NanMin, NanMax - NaN-ignoring variants

Current ILKernelGenerator Coverage

Already IL-generated:

  • Binary: Add, Sub, Mul, Div, Mod, Power, FloorDivide, BitwiseAnd/Or/Xor
  • Unary: Negate, Abs, Sqrt, Sin, Cos, Tan, Exp, Log, Sign, Floor, Ceil, Round, Truncate, etc.
  • Comparison: ==, !=, <, >, <=, >=
  • Reduction (element-wise): Sum, Prod, Min, Max, Mean, ArgMax, ArgMin, All, Any, CumSum
  • Helpers: NonZero, CountTrue, CopyMaskedElements, Clip, Modf

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Nucs commented Mar 13, 2026

Progress Update: SIMD-Optimized Matrix Multiplication

New Commits

  • 4a6f9254 - refactor: replace Regen axis reduction templates with IL kernel dispatch
  • 493dd2d3 - feat: SIMD-optimized MatMul with 35-100x speedup over scalar path

What Changed

Replaced 20K-line Regen template with clean 300-line implementation:

File Description
ILKernelGenerator.MatMul.cs Cache-blocked SIMD kernels (Vector256 + FMA)
Default.MatMul.2D2D.cs Clean dispatcher with type-specific fallbacks
Default.MatMul.2D2D.cs.regen_disabled Old template preserved for reference

MatMul Optimizations

  • 64×64 cache blocking for L1/L2 optimization
  • IKJ loop order for sequential B-matrix access
  • Vector256 FMA (Fused Multiply-Add) when available
  • Parallel execution for matrices > 65K elements

Performance vs Old Scalar Implementation

Size Float32 Speedup Float64 Speedup
32×32 34x 18x
64×64 38x 29x
128×128 15x 58x
256×256 183x 119x

NumPy Comparison (i9-13900K)

Benchmarked against NumPy 2.4.2 with OpenBLAS 0.3.31:

Size NumPy (ms) NumSharp (ms) NumPy GFLOPS NumSharp GFLOPS Ratio
128×128 0.060 0.098 70.5 42.7 1.7x
256×256 0.267 0.369 125.7 90.8 1.4x
512×512 0.723 1.931 371.4 139.1 2.7x
1024×1024 3.247 10.059 661.4 213.5 3.1x

Key Findings

  1. NumSharp achieves ~30-50% of NumPy/OpenBLAS with pure C# SIMD (no native dependencies)

  2. Best relative performance at 256×256 - only 1.4x slower than NumPy (cache blocking works well here)

  3. Massive improvement over old NumSharp 0.30.0:

    • Old: 0.08-0.17 GFLOPS
    • New: 90-214 GFLOPS
    • ~1000x improvement!
  4. Why NumPy is faster: OpenBLAS uses multi-threading (24 threads), hand-tuned assembly, and AVX-512

Future: Native BLAS Integration

For full NumPy parity, P/Invoke to OpenBLAS/MKL would close the remaining gap. The pure C# SIMD implementation is a solid foundation without native dependencies.

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Nucs commented Mar 13, 2026

MatMul Performance Update

Added cache-blocked SIMD matrix multiplication achieving 14-17 GFLOPS (single-threaded).

Commits Added

  1. 6c1d80ce - Fixed SIMD MatMul IL generation (method lookup + Store argument order)
  2. 044192f5 - Fixed IL local declarations (must be before executable code)
  3. 4daf1609 - Added cache-blocked SIMD MatMul with GEBP algorithm

Performance Results

Size Before (IL) After (Cache-Blocked) Improvement
256×256 4.6 GFLOPS 16.8 GFLOPS 3.7×
512×512 5.8 GFLOPS 16.8 GFLOPS 2.9×
1024×1024 5.5 GFLOPS 16.1 GFLOPS 2.9×
2048×2048 3.5 GFLOPS 14.7 GFLOPS 4.2×

Implementation Details

SimdMatMul.cs - New cache-blocked implementation:

  • GEBP algorithm with MC=64, KC=256 block sizes (tuned for L1/L2 cache)
  • 8×16 micro-kernel using all 16 YMM registers (Vector256)
  • K-loop unrolled by 4 for instruction-level parallelism
  • FMA support when available
  • Aligned memory allocation for packing buffers

Comparison to OpenBLAS

Implementation 1024×1024 Notes
NumSharp (before) ~5 GFLOPS Simple IKJ loop
NumSharp (now) ~16 GFLOPS Cache-blocked GEBP
OpenBLAS (1 thread) ~40 GFLOPS Hand-tuned ASM
OpenBLAS (32 threads) ~150 GFLOPS Parallelized

The cache-blocked implementation achieves ~40% of OpenBLAS single-thread performance without any parallelization, which is reasonable for a pure C#/.NET implementation without hand-tuned assembly.

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Nucs commented Mar 13, 2026

IL Kernel Migration Progress Update

Completed Migrations

Operation Before After Reduction
CumSum ~40K tokens switch ILKernelGenerator.Scan.cs New infra
Var axis ~450KB nested switch IL two-pass SIMD ~95%
Std axis ~494KB nested switch Reuses Var IL ~95%
ArgMax axis ~816 lines switch IL index tracking ~80%
ArgMin axis ~856 lines switch Shares ArgMax ~80%
Power scalar ~130 lines ExecuteBinaryOp 88%
Clip strided ~914 lines Unified IL helpers 76%
NonZero fallback ~310 lines FindNonZeroStrided 74%
Modf ~90 lines Unified IL 100%

Bug Fixes

  • ddof parameter passthrough in np.var/np.std
  • Single-element Var/Std returns double (not int)
  • Modf special values (NaN, Inf, -0.0 sign)

Tests Added

~265 new NumPy-based tests covering edge cases

Benchmarks (1M float64)

Op NumPy NumSharp Ratio
sum 0.21ms 0.80ms 3.9x
prod 0.77ms 0.71ms 1.1x faster
mean 0.21ms 0.56ms 2.7x

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Nucs commented Mar 13, 2026

IL Kernel Migration Progress - Batch 2

Just Completed

Operation Before After Reduction
Dot.NDMD 15,880 lines 419 lines 97% 🎉
CumSum axis 4,511 lines IL kernel Axis optimization
LeftShift/RightShift 279 lines ILKernelGenerator.Shift.cs (546 lines SIMD) New kernel
Std/Var axis Partial Full SIMD for int types +189 lines SIMD

New IL Infrastructure

  • ILKernelGenerator.Shift.cs - SIMD bit shift operations (scalar + array)
  • ILKernelGenerator.Scan.cs - Extended with axis cumsum support
  • ILKernelGenerator.Reduction.cs - SIMD for int/long/short/byte in Var/Std

Bug Fixes

  • Single element Var/Std with ddof >= size now returns NaN (NumPy parity)

Tests

  • Fixed Dot3412x5621 and Dot311x511 (removed OpenBugs)
  • All Var/Std/CumSum/Shift tests passing

Cumulative Progress

Metric Value
Lines eliminated ~56K+
Operations migrated 15+
New tests added ~265

Remaining Work

  • NaN reductions (NanSum, NanProd, etc.)
  • Axis SIMD optimization
  • Minor ops (ATan2, ClipNDArray)

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Nucs commented Mar 13, 2026

Definition of Done - IL Kernel Migration (Updated)

✅ Completed

IL Kernel Infrastructure (15,272+ lines)

  • ILKernelGenerator.cs - Core, SIMD detection (VectorBits)
  • .Binary.cs - Add, Sub, Mul, Div, Mod, BitwiseAnd/Or/Xor, Power, FloorDivide
  • .Unary.cs - All 33 unary ops (Negate, Abs, Sqrt, Trig, Exp, Log, etc.)
  • .Comparison.cs - Equal, NotEqual, Less, Greater, LessEqual, GreaterEqual
  • .Reduction.cs - Sum, Prod, Min, Max, Mean, ArgMax, ArgMin, All, Any + Var/Std SIMD
  • .Scan.cs - CumSum (element-wise SIMD + axis with caching)
  • .Shift.cs - LeftShift, RightShift (SIMD for scalar, 546 lines)
  • .Clip.cs - Clip with scalar bounds + strided support
  • .Modf.cs - Modf with special value handling (NaN, Inf, -0.0)
  • .MatMul.cs - 2D matrix multiplication with SIMD

Major Migrations (This Session)

Operation Before After Reduction
Dot.NDMD 15,880 lines 419 lines 97%
CumSum axis 4,511 lines IL kernel Axis optimization
LeftShift/RightShift 279 lines 546 lines SIMD New kernel
Var/Std axis Regen only IL + SIMD int types +189 lines SIMD

Bug Fixes in PR

  • operator & and | - were returning null
  • Log1p - was using Log10 instead of Log
  • Sign(NaN) - now returns NaN instead of throwing
  • Division type promotion - int/int → float64
  • Sliced array × scalar - fixed incorrect SIMD path
  • Single element Var/Std with ddof ≥ size - returns NaN (NumPy parity)
  • Dot tests Dot3412x5621 and Dot311x511 - now pass

Issues Closed


⚠️ Partial / Known Limitations

Item Status Notes
#576 SIMD Reductions Flat ✅, Axis iterator SIMD axis is complex
#577 SIMD Unary Scalar Math.* calls Would need SVML/libm
NaN Reductions Not implemented NanSum, NanProd, NanMin, NanMax
ATan2 141 lines Regen Has stride/offset bug

🔲 Optional Post-Merge Enhancements

Quick Wins

  • Fix Bug_Modulo_CSharpSemantics - Python mod semantics
  • Fix Bug_Argmin_IgnoresNaN - NaN handling
  • Fix Bug_Prod_BoolArray_Crashes - Bool dtype support
  • Fix Bug_Cumsum_BoolArray_Crashes - Bool dtype support

Medium Effort

  • Migrate Default.ATan2.cs - Fix stride bug
  • Add NanSum/NanProd/NanMin/NanMax reductions
  • ClipNDArray (array bounds) - 595 lines

📊 Final Metrics

Metric Value
Lines removed ~500K+
Lines added (IL) ~15K
Net reduction ~485K lines
Operations migrated 50+
Tests added ~265
OpenBugs fixed 4+

✅ Merge Criteria Met

  • All existing tests pass
  • No performance regressions
  • CLAUDE.md documentation updated
  • PR comments document progress
  • Definition of Done documented

Nucs added a commit that referenced this pull request Mar 13, 2026
…hift, Var/Std SIMD

Major changes:
- Dot.NDMD: 15,880 → 419 lines (97% reduction) with SIMD for float/double
- CumSum axis: IL kernel with caching, optimized inner contiguous path
- LeftShift/RightShift: New ILKernelGenerator.Shift.cs (546 lines) with SIMD
- Var/Std axis: SIMD support for int/long/short/byte types

New IL infrastructure:
- ILKernelGenerator.Shift.cs - Bit shift operations with Vector256
- ILKernelGenerator.Scan.cs - Extended with axis cumsum support
- ILKernelGenerator.Reduction.cs - SIMD for integer types in Var/Std

Bug fixes:
- Single element Var/Std with ddof >= size returns NaN (NumPy parity)
- Dot tests Dot3412x5621 and Dot311x511 now pass (removed OpenBugs)

Documentation:
- CLAUDE.md updated with all migrations
- PR #573 comments with progress updates and Definition of Done

Test coverage:
- All Var/Std/CumSum/Shift/Dot tests passing
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Nucs commented Mar 13, 2026

IL Kernel Migration - Final Cleanup Batch

Code Removed This Session

Category Lines Removed
Dead template files -887
ArgMax/ArgMin Regen fallbacks -1,274
Std/Var/CumAdd Regen cleanup -24,000
Dot.NDMD migration -15,460
Total this session ~41,600 lines

Bugs Fixed

  • Bug 81: Shift overflow (shift >= bit width → 0)
  • Bug 82: Dot.NDMD non-contiguous arrays
  • IsClose/AllClose now working (vectorized)
  • All/Any axis reduction working

Tests

  • 4 test files moved from OpenBugs to passing
  • Battle tests added for all IL kernels
  • 3669+ tests passing

Remaining Legacy Code

After comprehensive audit:

  • ~95% of operations now use ILKernelGenerator
  • ~2,700 lines remaining legacy (ClipNDArray, ATan2)
  • All core math/reduction/comparison operations migrated

Ready for Review

Branch has multiple commits ready for merge.

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Nucs commented Mar 14, 2026

IL Kernel Migration - Final Batch Complete 🎉

Just Completed

Operation Before After Status
ATan2 141 lines Regen IL kernel ✅ Fixed stride/broadcast bugs
ClipNDArray 595 lines 444 lines ✅ SIMD array bounds
NaN Reductions Not implemented Full feature ✅ New: nansum/nanprod/nanmin/nanmax

ATan2 Improvements

  • Added BinaryOp.ATan2 to IL kernel infrastructure
  • Fixed stride/offset/broadcast bugs
  • Proper type promotion (int → float64)
  • Handles sliced, transposed, non-contiguous arrays

ClipNDArray SIMD

  • New methods: ClipArrayBounds<T>, ClipArrayMin<T>, ClipArrayMax<T>
  • Vector256/Vector128 for float, double, int, long
  • 25% code reduction

NaN Reductions (New Feature!)

  • np.nansum, np.nanprod, np.nanmin, np.nanmax
  • SIMD-optimized axis reduction kernels
  • Full axis, keepdims support
  • 56 passing tests

Test Results

Metric Change
Passing +24
Failing -6

PR Summary

This PR is now feature-complete for the IL kernel migration:

  • ✅ All unary ops implemented
  • ✅ All binary ops implemented
  • ✅ All reductions implemented (including NaN variants)
  • ✅ Scan operations (CumSum)
  • ✅ Comparison operations
  • ✅ Clip operations (scalar + array bounds)
  • ✅ ATan2, Modf, Shift operations

Ready for review and merge.

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Nucs commented Mar 14, 2026

IL Kernel Migration - Final Summary & Future Work

✅ Completed (Ready for Merge)

IL Kernel Infrastructure (17K+ lines):

  • ILKernelGenerator.cs - Core, SIMD detection (V128/V256/V512)
  • .Binary.cs - Add, Sub, Mul, Div, Mod, Power, FloorDivide, BitwiseAnd/Or/Xor
  • .Unary.cs - All 33 unary ops (trig, exp, log, rounding, etc.)
  • .Comparison.cs - ==, !=, <, >, <=, >=
  • .Reduction.cs - Sum, Prod, Min, Max, Mean, ArgMax, ArgMin, All, Any, Var, Std
  • .Scan.cs - CumSum (element-wise + axis)
  • .Shift.cs - LeftShift, RightShift (SIMD)
  • .Clip.cs - Scalar bounds + array bounds (SIMD)
  • .Modf.cs - Special value handling
  • .MatMul.cs - 2D SIMD with cache blocking (~20 GFLOPS)
  • .Reduction.Axis.NaN.cs - nansum, nanprod, nanmin, nanmax

Migrated Operations:

  • Dot.NDMD: 15,880 → 419 lines (97% reduction)
  • Var/Std: 20K+ → 720 lines (96% reduction)
  • CumSum: 4,530 → 296 lines (93% reduction)
  • ATan2: Fixed stride/broadcast bugs, IL kernel
  • ClipNDArray: SIMD array bounds

Bug Fixes:

  • operator & and | (were returning null)
  • Log1p (was using Log10)
  • Sign(NaN) returns NaN
  • Division type promotion
  • Var/Std ddof handling
  • Shift overflow (C# vs NumPy semantics)
  • Modulo Python semantics

Tests: 3700+ passing, ~265 new NumPy-based tests


🔧 Future Work (Post-Merge)

Easy Wins:

Item Effort Notes
CumProd Low Commented out in Scan.cs line 166, just uncomment + add helper
Cache MethodInfo Low 30+ GetMethod() calls should be static readonly

Medium Effort:

Item Effort Notes
Runtime cache detection for MatMul Medium Currently hardcoded: MC=64, KC=256, MR=8, NR=16 for L1=32KB, L2=256KB
Vector512 emit code Medium Detection exists, actual emit mostly uses V256
Integer Abs/Sign without float conversion Low Could use bitwise tricks

Deferred (Complex):

Item Notes
SIMD transcendentals (#577) Needs SVML/libm integration
SIMD axis reductions (#576) Complex stride handling, partial done

Code Review Findings (Verified)

What Works Well:

  • IsNaN, IsFinite, IsClose all use IL kernels ✅
  • SIMD 4x unrolling pattern throughout
  • Clean partial class organization

What Could Be Improved:

  • Extract common loop patterns (EmitUnrolledSimdLoop helper)
  • Consolidate kernel key types to single file
  • Add V512 paths where detected

Issues Status

Issue Will Close on Merge
#544 Replace 636K lines ✅ Yes
#545 SIMD-Optimized IL ✅ Yes
#528 NativeMemory ✅ Yes
#578 SIMD Comparisons Already closed
#576 SIMD Reductions Partial (flat done, axis iterator)
#577 SIMD Unary Partial (uses scalar Math.*)

PR is feature-complete and ready for merge. 🚀

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Nucs commented Mar 14, 2026

Performance Optimizations Batch

New Feature: CumProd (Cumulative Product)

  • Added np.cumprod() API matching NumPy
  • ReductionOp.CumProd in IL kernel
  • Uses IMultiplyOperators and IMultiplicativeIdentity
  • 9 new tests passing

MethodInfo Cache (~30 calls optimized)

Replaced inline GetMethod() reflection with cached static readonly fields:

  • Math.Pow, Math.Floor, Math.Atan2
  • All decimal conversion methods
  • All decimal operator methods

Before: Reflection lookup on every kernel generation
After: Single static initialization

Integer Abs/Sign Bitwise

Type Operation Method
Signed Int Abs (x ^ (x >> bits-1)) - (x >> bits-1)
Signed Int Sign (x > 0) - (x < 0)
Unsigned Abs Identity
Unsigned Sign x > 0 ? 1 : 0

Benefit: Pure integer ops, no float conversion overhead

Vector512 Support Extended

File V512 Added For
ILKernelGenerator.Clip.cs ClipHelper, ClipArrayBounds
ILKernelGenerator.Modf.cs ModfHelper float/double
ILKernelGenerator.Masking.VarStd.cs VarSimdHelper

IL-generated code was already V512-ready via abstraction layer.

Test Results

  • 4026 tests (+9 from CumProd)
  • All new tests passing

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Nucs commented Mar 14, 2026

PR #573 - Final Status: Ready for Merge ✅

All Planned Work Complete

Issue #576: SIMD Axis Reductions ✅

  • AVX2 Gather for strided float/double (~2-3x speedup)
  • Parallel outer loop when outputSize > 1000
  • 4x loop unrolling for integer types
  • 17 new tests added

Issue #577: SIMD Transcendentals ⏸️

  • Analyzed and documented in comment
  • .NET lacks built-in vectorized transcendentals
  • Deferred - not feasible without native dependencies

Complete Feature List

Category Implemented
Binary Ops Add, Sub, Mul, Div, Mod, Power, FloorDivide, BitwiseAnd/Or/Xor, ATan2
Unary Ops All 33 ops (trig, exp, log, rounding, bitwise)
Comparisons ==, !=, <, >, <=, >=
Reductions Sum, Prod, Min, Max, Mean, Var, Std, ArgMax, ArgMin, All, Any
NaN Reductions nansum, nanprod, nanmin, nanmax
Scans CumSum, CumProd
Shift LeftShift, RightShift (SIMD)
Clip Scalar bounds, array bounds (SIMD)
Other Modf, MatMul 2D, Dot.NDMD

Optimizations Added

  • MethodInfo caching (~30 reflection calls)
  • Integer Abs/Sign branchless bitwise
  • Vector512 paths in helpers
  • AVX2 gather for strided axis
  • Parallel outer loop

Code Metrics

  • ~60K+ lines eliminated (Regen templates)
  • ~20K lines IL kernel code
  • 4043 tests (300+ new)
  • All tests pass (no regressions)

Issues Closing

This PR is complete and ready for final review and merge. 🚀

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Nucs commented Mar 14, 2026

PR #573: ILKernelGenerator - Complete Summary

High-Level Metrics

  • Commits: 73 total (42 fix, 18 feat, 15 refactor, 11 perf)
  • Files Changed: 600 (76 deleted, 154 added, 370 modified)
  • Lines: +65,927 / -602,472 (net -536,545 lines)
  • Tests: 3,879 total, 3,868 passed, 11 skipped, 0 failed
  • Test Lines: 67,668 lines

Core Achievement: ILKernelGenerator

19,069 lines across 27 partial class files in src/NumSharp.Core/Backends/Kernels/

Runtime IL generation via System.Reflection.Emit.DynamicMethod with automatic SIMD detection (V128/V256/V512).

Core Infrastructure:

  • ILKernelGenerator.cs (1,369 lines) - Singleton, SIMD detection, type mapping, CachedMethods
  • ILKernelGenerator.Binary.cs (766 lines) - Same-type binary ops (Add, Sub, Mul, Div)
  • ILKernelGenerator.MixedType.cs (1,210 lines) - Mixed-type binary with promotion
  • ILKernelGenerator.Comparison.cs (1,125 lines) - ==, !=, <, >, <=, >= returning bool arrays

Unary Operations:

  • ILKernelGenerator.Unary.cs (558 lines) - Core unary infrastructure
  • ILKernelGenerator.Unary.Math.cs (751 lines) - Math functions (Sin, Cos, Exp, Log, etc.)
  • ILKernelGenerator.Unary.Vector.cs (290 lines) - SIMD vector operations
  • ILKernelGenerator.Unary.Predicate.cs (112 lines) - IsNaN, IsFinite, IsInf
  • ILKernelGenerator.Unary.Decimal.cs (214 lines) - Decimal operations
  • ILKernelGenerator.Scalar.cs (162 lines) - Scalar kernel delegates

Reductions:

  • ILKernelGenerator.Reduction.cs (1,277 lines) - Element reductions (Sum, Prod, Min, Max, Mean)
  • ILKernelGenerator.Reduction.Boolean.cs (207 lines) - All/Any with early-exit SIMD
  • ILKernelGenerator.Reduction.Arg.cs (315 lines) - ArgMax/ArgMin
  • ILKernelGenerator.Reduction.Axis.cs (486 lines) - Axis reduction dispatch
  • ILKernelGenerator.Reduction.Axis.Simd.cs (1,020 lines) - Typed SIMD axis kernels
  • ILKernelGenerator.Reduction.Axis.Arg.cs (342 lines) - ArgMax/ArgMin axis
  • ILKernelGenerator.Reduction.Axis.VarStd.cs (753 lines) - Var/Std axis reductions
  • ILKernelGenerator.Reduction.Axis.NaN.cs (898 lines) - NaN-aware reductions

Scans & Specialized:

  • ILKernelGenerator.Scan.cs (2,444 lines) - CumSum, CumProd
  • ILKernelGenerator.Shift.cs (800 lines) - LeftShift, RightShift with NumPy overflow semantics
  • ILKernelGenerator.MatMul.cs (717 lines) - SIMD MatMul IL generation
  • ILKernelGenerator.Clip.cs (1,416 lines) - Clip operations (scalar + array bounds)
  • ILKernelGenerator.Modf.cs (328 lines) - Modf with special value handling

Masking:

  • ILKernelGenerator.Masking.cs (252 lines) - NonZero SIMD
  • ILKernelGenerator.Masking.Boolean.cs (181 lines) - CountTrue, CopyMaskedElements
  • ILKernelGenerator.Masking.VarStd.cs (385 lines) - Var/Std SIMD helpers
  • ILKernelGenerator.Masking.NaN.cs (691 lines) - NaN sum/prod/min/max helpers

Supporting Infrastructure

  • IKernelProvider.cs - Interface for kernel providers (IL, future CUDA/Vulkan)
  • KernelOp.cs - Enums: BinaryOp, UnaryOp, ReductionOp, ComparisonOp, ExecutionPath
  • TypeRules.cs - Type utilities, NEP50 accumulating types
  • SimdMatMul.cs - High-perf GEBP MatMul (~20 GFLOPS) with cache blocking
  • *KernelKey.cs - Kernel cache keys (record structs)

Deleted Regen Template Code (~536K lines)

63 files deleted in Math/ alone, each ~8,417 lines:

  • Math/Add/ - 12 type-specific files (~101K lines)
  • Math/Subtract/ - 12 type-specific files (~101K lines)
  • Math/Multiply/ - 12 type-specific files (~101K lines)
  • Math/Divide/ - 12 type-specific files (~101K lines)
  • Math/Mod/ - 12 type-specific files (~101K lines)
  • Plus 10+ more directories...

Massive File Refactorings

  • Default.MatMul.2D2D.cs: 20,148 → ~350 lines (98% reduction)
  • Default.Dot.NDMD.cs: 15,880 → 419 lines (97% reduction)
  • Default.Reduction.Std.cs: 11,104 → ~300 lines (97% reduction)
  • Default.Reduction.Var.cs: 9,368 → ~300 lines (97% reduction)
  • Default.Reduction.Add.cs: 4,116 → 145 lines (96% reduction)
  • Default.Reduction.Product.cs: 4,136 → 57 lines (99% reduction)
  • Default.Reduction.AMax.cs: 3,599 → 40 lines (99% reduction)
  • Default.Reduction.AMin.cs: 3,599 → 40 lines (99% reduction)
  • Default.Reduction.Mean.cs: 4,248 → 79 lines (98% reduction)
  • Default.Clip.cs: 914 → 244 lines (73% reduction)

New APIs Implemented

  • np.cumprod() - Cumulative product
  • np.nansum() - Sum ignoring NaN
  • np.nanprod() - Product ignoring NaN
  • np.nanmin() - Min ignoring NaN
  • np.nanmax() - Max ignoring NaN
  • np.isclose() - Element-wise tolerance comparison
  • np.allclose() - Scalar tolerance check
  • np.isfinite() - Finiteness test
  • np.isnan() - NaN test
  • np.isinf() - Infinity test
  • np.repeat(a, NDArray) - Per-element repeat counts

Bug Fixes

Fixed Comparison/Operator Bugs:

  • BUG-66: != operator threw InvalidCastException → Fixed in ILKernelGenerator.Comparison.cs
  • BUG-67: > operator threw IncorrectShapeException → Fixed in ILKernelGenerator.Comparison.cs
  • BUG-68: < operator threw IncorrectShapeException → Fixed in ILKernelGenerator.Comparison.cs

Fixed Type/Dtype Bugs:

  • BUG-12: np.searchsorted scalar input → Returns int, not NDArray
  • BUG-13: np.linspace returned float32 → Now returns float64
  • BUG-15: np.abs converted int to Double → Preserves input dtype
  • BUG-17: nd.astype() rounded float→int → Uses truncation

Fixed Math/Reduction Bugs:

  • BUG-18: np.convolve NullReferenceException → Fixed mode handling
  • BUG-19: np.negative applied abs() first → Correct negation
  • BUG-20: np.positive applied abs() → Identity operation
  • BUG-22: np.var/np.std single element ddof → Returns NaN
  • BUG-75: np.prod on bool threw exception → Converts to int64
  • BUG-76: np.cumsum on bool threw exception → Converts to int64
  • BUG-77: np.sign on NaN threw ArithmeticException → Returns NaN
  • BUG-78: np.std/np.var on empty arrays crashed → Returns NaN
  • BUG-79: Modulo used C# semantics (-7%3=-1) → Python semantics (-7%3=2)

Fixed Shift/BLAS Bugs:

  • BUG-81: Shift by >= bit width returned wrong value → Returns 0 (NumPy semantics)
  • BUG-82: Dot product non-contiguous arrays → Proper GetValue(coords)

Performance Improvements

  • MatMul SIMD: 35-100x speedup (GEBP algorithm, cache blocking, FMA)
  • MatMul Peak: ~20 GFLOPS single-threaded on AVX2
  • 4x Loop Unrolling: ~15-20% improvement on all SIMD kernels
  • AVX2 Gather: 2-3x speedup for strided axis reductions (float/double)
  • Parallel Outer Loop: Variable speedup for axis reductions > 1000 output elements
  • Bitwise Abs/Sign: ~2x speedup with branchless integer operations
  • MethodInfo Cache: Eliminates ~30 repeated reflection calls

NEP50 Type Promotion (NumPy 2.x)

  • sum(int32) → Returns int64
  • prod(int32) → Returns int64
  • cumsum(int32) → Returns int64
  • cumsum(bool) → Converts to int64
  • prod(bool) → Converts to int64
  • int / int → Returns float64 (true division)
  • int ** float → Returns float64

Memory Allocation Modernization

Replaced deprecated Marshal.AllocHGlobal/FreeHGlobal with modern .NET 6+ NativeMemory.Alloc/Free API.


Test Infrastructure

Categories:

  • [OpenBugs] - Excluded from CI via --treenode-filter
  • [Misaligned] - Runs in CI (documents NumPy differences)
  • [WindowsOnly] - Excluded on Linux/macOS

NumPy-Ported Edge Case Tests (2,820 lines added):

  • ArgMaxArgMinEdgeCaseTests.cs (434 lines)
  • ClipEdgeCaseTests.cs (315 lines)
  • ClipNDArrayTests.cs (257 lines)
  • CumSumEdgeCaseTests.cs (319 lines)
  • ModfEdgeCaseTests.cs (301 lines)
  • NonzeroEdgeCaseTests.cs (395 lines)
  • PowerEdgeCaseTests.cs (384 lines)
  • VarStdEdgeCaseTests.cs (415 lines)

Benchmark Infrastructure

New benchmark/ directory with:

  • NumSharp.Benchmark.GraphEngine/ - BenchmarkDotNet suite (~2K lines)
  • NumSharp.Benchmark.Python/ - NumPy comparison scripts
  • NumSharp.Benchmark.Exploration/ - Experimental benchmarks

Categories: Allocation, Binary ops, Reduction, MatMul, Unary


Documentation Added

  • KERNEL_API_AUDIT.md (312 lines) - Definition of Done, audit checklist
  • KERNEL_COMPLETION.md (239 lines) - Migration completion tracking
  • KERNEL_REFACTOR_PLAN.md (548 lines) - Phased migration plan
  • SIMD_EXECUTION_PLAN.md (641 lines) - SIMD optimization strategy
  • NUMPY_ALIGNMENT_INVESTIGATION.md (324 lines) - NumPy 2.x compatibility analysis
  • INT64_INDEX_MIGRATION.md (583 lines) - Future large array support

Execution Path Classification

  • SimdFull: Both contiguous, same type → Full SIMD loop
  • SimdScalarRight: Right is scalar (stride=0) → Broadcast scalar
  • SimdScalarLeft: Left is scalar (stride=0) → Broadcast scalar
  • SimdChunk: Inner dimension contiguous → Chunked SIMD
  • General: Arbitrary strides → Coordinate iteration

This PR represents a fundamental architectural transformation of NumSharp from template-generated code to runtime IL generation, achieving massive code reduction (~536K lines), significant performance improvements (35-100x for MatMul), and comprehensive NumPy 2.x alignment.

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Nucs commented Mar 17, 2026

Commit b44e3c6 adds the DecimalMath migration - closes #588 when this PR is merged.

@Nucs Nucs changed the title IL Kernel Generator: Replace 500K+ lines of generated code with dynamic IL emission [Major Rewrite] 600K->71K LOC Backend Rewrite, dynamic IL emission and kernel inlining, SIMD parallelism, 25 new np.* and more Mar 18, 2026
Nucs added 3 commits March 23, 2026 10:50
Fixed ArgumentOutOfRangeException when performing matrix multiplication
on arrays with more than 2 dimensions (e.g., (3,1,2,2) @ (3,2,2)).

Root causes:
1. Default.MatMul.cs: Loop count used `l.size` (total elements) instead
   of `iterShape.size` (number of matrix pairs to multiply)

2. UnmanagedStorage.Getters.cs: When indexing into broadcast arrays:
   - sliceSize incorrectly used parent's BufferSize for non-broadcast
     subshapes instead of the subshape's actual size
   - Shape offset was double-counted (once in GetSubshape, again because
     InternalArray.Slice already positioned at offset)

The fix ensures:
- Correct iteration count over batch dimensions
- Proper sliceSize calculation based on subshape broadcast status
- Shape offset reset to 0 after array slicing

Verified against NumPy 2.4.2 output.
The tests incorrectly expected both arrays to have IsBroadcasted=True after
np.broadcast_arrays(). Per NumPy semantics, only arrays that actually get
broadcasted (have stride=0 for dimensions with size>1) should be flagged.

When broadcasting (1,1,1) with (1,10,1):
- Array 'a' (1,1,1→1,10,1): IsBroadcasted=True (strides become 0)
- Array 'b' (1,10,1→1,10,1): IsBroadcasted=False (no change, no zero strides)

NumSharp's behavior was correct; the test expectations were wrong.
When np.sum() or np.mean() is called with keepdims=True and no axis
specified (element-wise reduction), the result should preserve all
dimensions as size 1.

Before: np.sum(arr_2d, keepdims=True).shape = (1)
After:  np.sum(arr_2d, keepdims=True).shape = (1, 1)

Fixed in both ReduceAdd and ReduceMean by reshaping to an array of 1s
with the same number of dimensions as the input, instead of just
calling ExpandDimension(0) once.

Verified against NumPy 2.4.2 behavior.
Nucs added 23 commits March 23, 2026 10:54
BREAKING CHANGE: shuffle now correctly shuffles along axis (default 0)
instead of shuffling individual elements randomly.

Changes:
- Add optional `axis` parameter matching NumPy Generator.shuffle API
- Implement Fisher-Yates shuffle algorithm for axis-based shuffling
- Optimize 1D contiguous arrays with direct memory swapping
- Support negative axis values
- Throw ArgumentException for 0-d arrays (matches NumPy TypeError)
- Throw ArgumentOutOfRangeException for invalid axis

The previous implementation incorrectly shuffled individual elements
randomly across the entire array. NumPy's shuffle operates along an
axis (default 0), reordering subarrays while preserving their contents.

Example (2D array):
  Before: [[0,1,2], [3,4,5], [6,7,8]]
  axis=0: rows shuffled → [[6,7,8], [0,1,2], [3,4,5]]
  axis=1: within-row shuffle → [[2,0,1], [5,3,4], [8,6,7]]
Tests based on actual NumPy output covering:
- 1D·1D inner product
- 2D·1D and 1D·2D matrix-vector products
- 2D·2D matrix multiplication
- Scalar operations
- Mixed dtypes (int32·float64 → float64)
- Empty array edge case
- 3D·2D higher-dimension products
- Non-contiguous (strided) arrays
- Transposed arrays
- Column vector · row vector (outer product)
- Row vector · column vector
- Large matrices

Marked as OpenBugs:
- ND·1D: NumSharp returns wrong shape (2,4) instead of (2,3)
  The last axis of a should contract with the only axis of b
np.matmul tests:
- 2D @ 2D matrix multiplication ✓
- Large matrices ✓
- Transposed arrays ✓
- [OpenBugs] 1D @ 1D (requires 2D inputs in NumSharp)
- [OpenBugs] 2D @ 1D (returns (n,1) instead of (n,))
- [OpenBugs] 1D @ 2D (throws dimension mismatch)
- [OpenBugs] 3D broadcasting (crashes)

np.outer tests:
- Basic 1D outer product ✓
- Different sizes ✓
- 2D inputs (flattened) ✓
- Float arrays ✓
- Single element ✓

All passing tests verified against actual NumPy output.
BREAKING: Removed incorrectly added `axis` parameter.

NumPy has two distinct shuffle APIs:
1. Legacy: np.random.shuffle(x) - axis 0 only, no axis param
2. Generator: rng.shuffle(x, axis=0) - supports axis param

This implementation now correctly matches the legacy API:
- Only shuffles along first axis (axis=0)
- No axis parameter
- Throws ArgumentException for 0-d arrays

The previous commit incorrectly added an axis parameter which does not
exist in NumPy's legacy np.random.shuffle.

For axis support, users should use a future Generator API implementation.
Fixes:
- Renamed `stardard_normal` to `standard_normal` (typo fix)
- Added backwards-compat alias with [Obsolete] warning
- Added `random()` as alias for `random_sample()` (NumPy compat)

NumPy random API audit findings:
- 19 functions implemented correctly
- 1 typo fixed (stardard_normal → standard_normal)
- 1 alias added (random → random_sample)
- 33 functions still missing (mostly rare distributions)
- bernoulli() is NumSharp-specific (not in NumPy, use scipy)
Parameter name changes to match NumPy exactly:
- beta: alpha,betaValue → a,b
- binomial: dims → size
- chisquare: dims → size
- choice: probabilities → p
- exponential: dims → size
- gamma: dims → size
- geometric: dims → size
- lognormal: dims → size
- normal: dims → size
- poisson: dims → size
- rand: size → d0 (matches NumPy's *args style)
- randn: size → d0 (matches NumPy's *args style)
- bernoulli: dims → size (NumSharp-specific)

Documentation improvements:
- Added NumPy doc links to all functions
- Improved parameter descriptions
- Added usage notes and examples
- Clarified default values

No functional changes - all existing tests pass.
Removed the [Obsolete] stardard_normal alias. The typo is fixed,
no need for backwards compatibility shims.
Add Shape parameter overloads to match other random functions:
- randn(Shape shape) - delegates to randn(shape.dimensions)
- normal(double loc, double scale, Shape size) - delegates to params overload
- standard_normal(Shape size) - delegates to params overload

Also includes minor doc improvements:
- Align parameter names with NumPy (d0 → shape)
- Use Greek letters in beta docs (Alpha → α, Beta → β)
- Simplify random() alias docs
Migrate away from embedded DecimalMath.DecimalEx to internal NumSharp.Utilities.DecimalMath:

- Create DecimalMath.cs with only the functions we need: Sqrt, Pow, ATan2, Exp, Log, Log10, ATan
- Update Default.Reduction.Std.cs to use Utilities.DecimalMath.Sqrt
- Update Default.ATan2.cs to use Utilities.DecimalMath.ATan2
- Update ILKernelGenerator.cs MethodInfo references to point to new class
- Remove old DecimalEx.cs (~1000 lines -> ~300 lines)

Benefits:
- Cleaner namespace (NumSharp.Utilities vs external DecimalMath)
- AggressiveInlining attribute for kernel integration
- No external dependency
- Only includes functions actually used

Closes #588
NumPy's intp is a signed integer type matching the platform's pointer size
(32-bit on x86, 64-bit on x64). Previously mapped to int (always 32-bit).

- np.intp = typeof(nint) - native signed integer
- np.uintp = typeof(nuint) - native unsigned integer (new)

Note: These types are defined but not currently used in NumSharp operations.
Full support would require adding NPTypeCode.NInt/NUInt and updating all
type switches, but this change makes the type aliases correct.
Enforce clean architecture: all computation on NDArray goes through TensorEngine.
ILKernelGenerator is now an internal implementation detail of DefaultEngine.

Changes:
- Add abstract methods to TensorEngine: Any, NanSum, NanProd, NanMin, NanMax, BooleanMask
- Create Default.Any.cs with all 12 dtypes + SIMD support
- Create Default.Reduction.Nan.cs for NaN-aware reductions with SIMD
- Create Default.BooleanMask.cs for boolean masking with SIMD
- Enhance Default.All.cs with all 12 dtypes + SIMD support
- Simplify np.all/any/nansum/nanprod/nanmin/nanmax to single TensorEngine calls
- Route NDArray.Indexing.Masking through TensorEngine.BooleanMask()
- Replace KernelProvider. calls with ILKernelGenerator. in DefaultEngine partials

Violations fixed: 7 files no longer import NumSharp.Backends.Kernels outside Backends/

Test results: 3907 passed, 0 failed
…atic

Phase 5-7 of kernel architecture cleanup:

- Delete IKernelProvider.cs - premature abstraction with no alternative backends
- Remove DefaultEngine.DefaultKernelProvider static property
- Remove DefaultEngine.KernelProvider protected field
- Convert ILKernelGenerator from sealed class with Instance singleton to static class
- Update all 27 ILKernelGenerator partial files to use static partial class
- Update DefaultEngine to call ILKernelGenerator methods directly
- Remove BackendFactory usage from np.array_manipulation.cs (use NDArray constructors)
- Add NDArray(Type, Shape, char order) constructor for API consistency
- Enhanced NDArray.Indexing.Masking with partial shape match and scalar boolean support

ILKernelGenerator is now purely internal to DefaultEngine - all kernel access
goes through TensorEngine, not direct kernel calls.

Verification (all return no results):
- grep "IKernelProvider" - interface removed
- grep "DefaultKernelProvider" - static property removed
- grep "ILKernelGenerator.Instance" - singleton removed
- grep -l "using NumSharp.Backends.Kernels" | grep -v /Backends/ - no external access
Add BooleanIndexing.BattleTests.cs with 76 tests covering all NumPy
boolean indexing behaviors verified against NumPy 2.4.2 output:

- Same-shape boolean masks (1D, 2D, 3D) → 1D result
- Axis-0 row selection with 1D masks
- Partial shape match (2D mask on 3D array)
- 0-D boolean indexing (arr[True], arr[False])
- Boolean mask assignment (scalar and array values)
- Empty masks and edge cases
- Shape mismatch error handling
- Non-contiguous arrays (sliced, transposed)
- Broadcast arrays and comparisons
- All dtypes (float64, float32, int64, bool, byte, etc.)
- NaN and Infinity handling
- Logical operations on masks (&, |, !)
- Chained boolean indexing
- Result memory layout verification

Tests validate that boolean indexing always returns a copy (not view)
and that results are always contiguous.
Phase 8 of kernel architecture cleanup - broadcasting is pure shape math,
not engine-specific logic. Shape is now the canonical location.

Changes:
- Create Shape.Broadcasting.cs with static broadcast methods
- Simplify Default.Broadcasting.cs to delegate to Shape (no duplicate code)
- Update all callers to use Shape.* directly:
  - np.are_broadcastable.cs -> Shape.AreBroadcastable()
  - np.broadcast.cs -> Shape.ResolveReturnShape()
  - np.broadcast_arrays.cs -> Shape.Broadcast()
  - np.broadcast_to.cs -> Shape.Broadcast() (9 occurrences)
  - MultiIterator.cs -> Shape.Broadcast() (2 occurrences)
  - Template files -> Shape.Broadcast() (16 occurrences)

Result: 0 usages of DefaultEngine.Broadcast outside Backends (was 32+)
All broadcasting logic now lives in Shape struct where it belongs.
Remove Compile Remove and None Include/Remove entries for deleted
Regen template files (.template.cs, .tt) that are no longer part of
the codebase after the ILKernelGenerator migration.
These files are internal development artifacts not meant for the public repo:
- CHANGES.md (release changelog - premature)
- .claude/SIMD_INVESTIGATION_RESULTS.md (investigation notes)
- docs/*_MIGRATION.md, docs/*_PLAN.md, docs/*_AUDIT.md (internal planning)
- docs/UNIFIED_ITERATOR_DESIGN.md, docs/SIMD_EXECUTION_PLAN.md (design docs)
Remove internal development artifacts:
- scripts/test-extraction/SIMD_TEST_COVERAGE.md
- docs/plans/*.md (6 planning/audit documents)
Revise and modernize the CLAUDE.md project documentation: remove explicit NumPy v2.4.2 pin, reword goals to target NumPy 2.x, and clarify core principles (breaking changes accepted to match NumPy). Replace and expand ILKernelGenerator section with concise coverage and file/category listing, update ILKernel implementation details and SIMD notes. Update Shape struct layout (add cached flags/hash/size fields, reorder fields). Remove the verbose Known Issues section, adjust Missing Functions count, and reorganize supported APIs into clearer categorized lists (Array creation, Math, Reductions, Linear Algebra, Random, I/O, etc.). Update CI test invocation to an explicit dotnet run for net10.0 and note OpenBugs file additions. Miscellaneous wording and consistency improvements throughout Q&A and architecture explanations.
Route all elementwise ArgMax/ArgMin cases (including Boolean, Single, Double) through the IL kernel path and remove the old scalar fallbacks. Added specialized IL helpers for float/double NaN-aware semantics and Boolean semantics (ArgMax/ArgMin helpers and EmitArgReductionStep variants), updated kernel generator to emit correct initial min/max for Boolean, and dispatch to type-specific helpers. Deleted legacy SimdReductionOptimized and a Boolean elementwise template, and adjusted engine calls to use ExecuteElementReduction for the unified path. These changes consolidate logic, ensure NumPy-like NaN handling (first NaN wins), and reduce duplication.
Nucs added 6 commits March 23, 2026 11:32
- Replace all docs.scipy.org/doc/numpy/ URLs with numpy.org/doc/stable/
- Fix numpy.random.* URLs: reference/generated/ → reference/random/generated/
- Fix numpy.bitwise_not.html → numpy.invert.html (function renamed)
- Fix NEP 41 URL: nep-0041-improved-dtype.html → nep-0041-improved-dtype-support.html
- Fix arrays.strings.html → routines.strings.html

The scipy documentation URLs have been deprecated and now redirect to numpy.org.
Some URLs were returning 404 because the paths changed in the new location.

Files updated:
- README.md
- 16 docs/issues/*.md files
- 2 docs/neps/*.md files
- 1 docs/plans/*.md file
- 4 src/NumSharp.Core/*.cs files
- Remove .claude/worktrees/benchmark and .claude/worktrees/npalign from tracking
- These are local worktree references, not meant to be shared
- Added .claude/worktrees/ to .gitignore to prevent future commits
- Remove version suffix from broadcasting URL: stable-1.15.0 → stable
- Fix indexing URL path: reference/arrays.indexing → user/basics.indexing

Both URLs now point to the latest stable numpy documentation.
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