Add SIMD batch support to the distance, barrier, and friction functions

.github/workflows/coverage.yml

@@ -68,7 +68,7 @@ jobs:
         run: |
           cd build
           ctest --verbose -j ${{ steps.cpu-cores.outputs.count }}
-          lcov --directory . --capture --output-file coverage.info --ignore-errors inconsistent,format,gcov
+          lcov --directory . --capture --output-file coverage.info --ignore-errors inconsistent,format,gcov,mismatch
           lcov --remove coverage.info --ignore-errors unused '/usr/*' "$HOME/.cache/*" "*tests/*" --output-file coverage.info
 
       - name: Upload coverage reports to Codecov

.gitignore

@@ -675,4 +675,5 @@ CMakeGraphVizOptions.cmake
 .zed/*
 
 .claude
-graphify-out
+graphify-out
+__cmake_systeminformation

CLAUDE.md

@@ -40,6 +40,27 @@ cd build/test && ctest --verbose -R "test_name_pattern"
 ./build/test/ipc_toolkit_tests "[tag]"
 ```
 
+### Benchmarks
+
+Benchmarks are hidden Catch2 cases tagged `[!benchmark]`, so they don't run by
+default — but a tag filter like `"[simd]"` *will* pull them in alongside the
+unit tests. Exclude them explicitly when you only want correctness:
+
+```bash
+./build/test/ipc_toolkit_tests "[simd] ~[!benchmark]"
+```
+
+**Never take benchmark numbers from a `test`/`debug` build.** Those presets are
+`CMAKE_BUILD_TYPE=Debug`, where the templated kernels aren't inlined and the
+asserts are live, so the results are meaningless — and misleading, since the
+SIMD paths lean hardest on inlining and lose the most. Build a Release
+configuration with tests enabled and benchmark that instead:
+
+```bash
+cmake -S . -B build/benchmark -DCMAKE_BUILD_TYPE=Release -DIPC_TOOLKIT_BUILD_TESTS=ON
+cmake --build build/benchmark -j 8
+```
+
 ## Code Style
 
 - **Formatter:** clang-format, WebKit-based style, **80-character column limit**. Pre-commit hooks enforce this — always run before committing:

CMakeLists.txt

@@ -302,12 +302,16 @@ target_link_libraries(ipc_toolkit PRIVATE ipc::toolkit::warnings)
 
 # SIMD support
 if(IPC_TOOLKIT_WITH_SIMD)
-  # Add SIMD flags to compiler flags
-  target_compile_options(ipc_toolkit PRIVATE ${SIMD_CXX_FLAGS})
+  # Add SIMD flags to compiler flags.
+  # NOTE: PUBLIC because xsimd::default_arch is selected from each translation
+  # unit's own flags. ipc/utils/simd.hpp exposes batch types in the public API,
+  # and a consumer compiled without these flags would name a different type
+  # than the one instantiated in the library, failing to link.
+  target_compile_options(ipc_toolkit PUBLIC ${SIMD_CXX_FLAGS})
 
   # Link against cross-platform xsimd library
   include(xsimd)
-  target_link_libraries(ipc_toolkit PRIVATE xsimd::xsimd)
+  target_link_libraries(ipc_toolkit PUBLIC xsimd::xsimd)
 
   # Disable vectorization in Eigen since I've found it to have alignment issues.
   # NOTE: I don't know why this needs to be public, but it crashes if I make it private.
@@ -339,6 +343,7 @@ endif()
 
 if(IPC_TOOLKIT_WITH_CODE_COVERAGE AND CMAKE_CXX_COMPILER_ID MATCHES "GNU|Clang")
   # Add required flags (GCC & LLVM/Clang)
+  # NOTE: tests/CMakeLists.txt repeats these for the test target; keep in sync.
   target_compile_options(ipc_toolkit PRIVATE
     -g         # generate debug info
     --coverage # sets all required flags

cmake/find/FindSIMD.cmake

@@ -180,8 +180,14 @@ function (test_sse_availability)
 
 endfunction()
 
-# This script checks for the highest level of FMA support on the host
-# by compiling and running small C++ programs that uses FMA intrinsics.
+# This script checks for x86 FMA3 support on the host by compiling and running
+# a small C++ program that uses the AVX2 FMA intrinsics.
+#
+# NOTE: This probe is x86-only -- it needs `-mavx2 -mfma` and <immintrin.h>, so
+# it cannot succeed on AArch64 and reports DETECTED_FMA3_X86 as failed there.
+# That is not a missing capability: AArch64 has no opt-in FMA flag because
+# fmadd/fmsub and the NEON vfmaq_* family are mandatory in the base ISA, so an
+# empty FMA_FLAGS is the correct answer and NEON implies a fused multiply-add.
 
 # If any  FMA support is detected, the following variables are set:
 #
@@ -194,7 +200,7 @@ endfunction()
 function (test_fma_availability)
 	set(FMA_FLAGS)
 	set(FMA_FOUND)
-	set(DETECTED_FMA)
+	set(DETECTED_FMA3_X86)
 
 	include(CheckCXXSourceRuns)
 	set(CMAKE_REQUIRED_FLAGS)
@@ -219,12 +225,12 @@ function (test_fma_availability)
 
 		__m256d result =  _mm256_fmsub_pd (a, b, c);
 		return 0;
-		}" DETECTED_FMA)
+		}" DETECTED_FMA3_X86)
 	endif()
 
 	set(CMAKE_REQUIRED_FLAGS)
 
-	if(DETECTED_FMA)
+	if(DETECTED_FMA3_X86)
 	  SET(FMA_FOUND 1)
 	  if(CMAKE_COMPILER_IS_GNUCC OR CMAKE_COMPILER_IS_GNUCXX OR CMAKE_CXX_COMPILER_ID MATCHES "Clang")
 		SET(FMA_FLAGS "${FMA_FLAGS} -mfma")

cmake/ipc_toolkit/ipc_toolkit_warnings.cmake

@@ -47,6 +47,7 @@ else()
     -Wpointer-arith
     -Wformat=2
     -Wuninitialized
+    -Wno-maybe-uninitialized
     -Wcast-qual
     -Wmissing-noreturn
     -Wmissing-format-attribute
@@ -179,6 +180,13 @@ else()
   if(NOT CMAKE_CXX_COMPILER_ID STREQUAL "GNU")
     list(APPEND IPC_TOOLKIT_WARNING_FLAGS -Wnull-dereference)
   endif()
+
+  # GCC 16 mis-analyzes TBB's enumerable_thread_specific. GCC <= 15 and Clang
+  # are clean, so only suppress it where it fires.
+  if(CMAKE_CXX_COMPILER_ID STREQUAL "GNU"
+     AND CMAKE_CXX_COMPILER_VERSION VERSION_GREATER_EQUAL 16)
+    list(APPEND IPC_TOOLKIT_WARNING_FLAGS -Wno-array-bounds)
+  endif()
 endif()
 
 add_library(ipc_toolkit_warnings INTERFACE)

cmake/recipes/meshfem_sparse.cmake

@@ -58,7 +58,9 @@ target_include_directories(MeshFEMSparse SYSTEM PUBLIC
 
 # MeshFEMCore's headers include the CMake-generated <MeshFEM_export.h>. We
 # build a static library, so the export macros are empty.
-file(WRITE "${CMAKE_CURRENT_BINARY_DIR}/meshfem/exports/MeshFEM_export.h" [[
+file(CONFIGURE
+    OUTPUT "${CMAKE_CURRENT_BINARY_DIR}/meshfem/exports/MeshFEM_export.h"
+    CONTENT [[
 #pragma once
 #define MESHFEM_EXPORT
 #define MESHFEM_NO_EXPORT

codecov.yml

@@ -10,4 +10,4 @@ coverage:
         threshold: 5%
         only_pulls: true
 ignore:
-  - "tests/*"
+  - "tests/**"

docs/source/_static/graphviz/dependencies.dot

@@ -2,7 +2,10 @@ digraph "IPC Toolkit Dependencies" {
     bgcolor = "transparent";
     splines = ortho;
     layout = dot;
-    nodesep = 0.2;
+    // 0.28 rather than 0.2: with less separation the ortho router has no room
+    // to turn igl_predicates -> igl_core and hairpins it into igl_core's west
+    // side, putting the arrowhead on top of the predicates node.
+    nodesep = 0.28;
     ranksep = 0.5;
     node [fontname = "Menlo"; style = filled; penwidth = 2;];
     edge [penwidth = 2; fontname = "Menlo";];
@@ -17,9 +20,13 @@ digraph "IPC Toolkit Dependencies" {
         legendNode0 [label = "Static Library";shape = box;style = "rounded,filled";fillcolor = "#D5E8D4";color = "#8FB976";];
         legendNode1 [label = "Shared Library";shape = box;style = "rounded,filled";fillcolor = "#CCE7F8";color = "#6596B2";];
         legendNode2 [label = "Interface Library";shape = box;style = "rounded,filled";fillcolor = "#FFE6CC";color = "#DAA52D";];
+        legendNode3 [label = "Optional Dependency";shape = box;style = "rounded,filled,dashed";fillcolor = "#F5F5F5";color = "#999999";fontcolor = "#555555";];
         legendNode0 -> legendNode1 [label = "Public"; color = "#8FB976"; fontcolor = "#8FB976";];
         legendNode2 -> legendNode0 [label = "Interface"; color = "#DAA52D"; fontcolor = "#DAA52D";];
         legendNode1 -> legendNode2 [label = "Private"; color = "#BE6562"; fontcolor = "#BE6562";];
+        // Dashed marks a dependency behind an IPC_TOOLKIT_WITH_* CMake option,
+        // independent of the link scope the edge colour encodes.
+        legendNode2 -> legendNode3 [label = "Optional"; style = "dashed"; color = "#999999"; fontcolor = "#555555";];
     }
     // Force ipc_toolkit to top
     subgraph {
@@ -40,18 +47,18 @@ digraph "IPC Toolkit Dependencies" {
     "node5" [label = "ipc_toolkit\n(ipc::toolkit)";shape = box;style = "rounded,filled";fillcolor = "#D5E8D4";color = "#8FB976";];
     "node5" -> "node0" [color = "#8FB976";];
     // ipc_toolkit -> Eigen3_Eigen
-    "node5" -> "node1" [color = "#8FB976";];
-    // ipc_toolkit -> filib
+    "node5" -> "node1" [color = "#8FB976"; style = "dashed";];
+    // ipc_toolkit -> filib (IPC_TOOLKIT_WITH_FILIB)
     "node5" -> "node2" [color = "#BE6562";];
     // ipc_toolkit -> igl_core
     "node5" -> "node3" [color = "#BE6562";];
     // ipc_toolkit -> igl_predicates
     "node15" [label = "xsimd\n(xsimd::xsimd)";shape = box;style = "rounded,filled";fillcolor = "#FFE6CC";color = "#DAA52D";];
-    "node5" -> "node15" [color = "#BE6562";];
-    // ipc_toolkit -> xsimd
+    "node5" -> "node15" [color = "#8FB976"; style = "dashed";];
+    // ipc_toolkit -> xsimd (IPC_TOOLKIT_WITH_SIMD)
     "node6" [label = "robin_map\n(tsl::robin_map)";shape = box;style = "rounded,filled";fillcolor = "#FFE6CC";color = "#DAA52D";];
-    "node5" -> "node6" [color = "#BE6562";];
-    // ipc_toolkit -> robin_map
+    "node5" -> "node6" [color = "#BE6562"; style = "dashed";];
+    // ipc_toolkit -> robin_map (IPC_TOOLKIT_WITH_ROBIN_MAP)
     "node7" [label = "scalable_ccd\n(scalable_ccd::scalable_ccd)";shape = box;style = "rounded,filled";fillcolor = "#D5E8D4";color = "#8FB976";];
     "node7" -> "node0" [color = "#8FB976";];
     // scalable_ccd -> Eigen3_Eigen
@@ -75,16 +82,20 @@ digraph "IPC Toolkit Dependencies" {
     "node5" -> "node11" [color = "#BE6562";];
     // ipc_toolkit -> tight_inclusion
     "node12" [label = "absl_hash\n(absl::hash)";shape = box;style = "rounded,filled";fillcolor = "#D5E8D4";color = "#8FB976";];
-    "node5" -> "node12" [color = "#BE6562";];
-    // ipc_toolkit -> TinyAD
+    "node5" -> "node12" [color = "#BE6562"; style = "dashed";];
+    // ipc_toolkit -> absl_hash (IPC_TOOLKIT_WITH_ABSEIL)
     "node13" [label = "TinyAD\n(TinyAD::TinyAD)";shape = box;style = "rounded,filled";fillcolor = "#D5E8D4";color = "#8FB976";];
     "node5" -> "node13" [color = "#8FB976";];
+    // ipc_toolkit -> TinyAD
     "node13" -> "node0" [color = "#BE6562";];
+    // TinyAD -> Eigen3_Eigen
     "node13" -> "node9" [color = "#BE6562";];
-    // ipc_toolkit -> nlohmann_json
-    "node14" [label = "nlohmann_json\n(nlohmann_json::nlohmann_json)";shape = box;style = "rounded,filled";fillcolor = "#FFE6CC";color = "#DAA52D";];
-    "node5" -> "node14" [color = "#8FB976";];
-    // ipc_toolkit -> tracy
-    "node16" [label = "TracyClient\n(Tracy::TracyClient)";shape = box;style = "rounded,filled";fillcolor = "#D5E8D4";color = "#8FB976";];
-    "node5" -> "node16" [color = "#8FB976";];
+    // TinyAD -> tbb
+    "node17" [label = "MeshFEMSparse\n(MeshFEM::Sparse)";shape = box;style = "rounded,filled";fillcolor = "#D5E8D4";color = "#8FB976";];
+    "node5" -> "node17" [color = "#BE6562"; style = "dashed";];
+    // ipc_toolkit -> MeshFEMSparse (IPC_TOOLKIT_WITH_MESHFEM_SPARSE)
+    "node17" -> "node0" [color = "#8FB976";];
+    // MeshFEMSparse -> Eigen3_Eigen
+    "node17" -> "node9" [color = "#8FB976";];
+    // MeshFEMSparse -> tbb
 }