fastfields · balbasty · Aug 20, 2026 · Aug 20, 2026
diff --git a/CLAUDE.md b/CLAUDE.md
@@ -182,6 +182,16 @@ pushpull's fully-static order×bound compile is nightly
  library, so those *are* `<cstdint>` there) and the non-nvcc `__device__` /
  `__host__` fallbacks. Prefer an `inline` function to a macro where one will
  do — a function in `ff::` is collision-safe without any prefix.
+- **`<fastfields/…>` for the public interface, `"…"` for private headers.**
+ `include/fastfields/` is what gets installed and what `fastfields-dlpack`
+ puts on its include path, so it is spelled with angle brackets like any other
+ installed dependency; a header reached relative to the including file
+ (`"../utils.h"`, `"flow/2d.h"`) keeps quotes. The two resolve identically
+ here — `make/common.mk`'s `-I$(ROOTDIR)/include` is the entire include
+ configuration and there is no `-iquote` anywhere — so this is about saying
+ which category a dependency is in, not about lookup.
+ `tools/normalise-include-delimiters.py --check` enforces it, and also checks
+ the converse: every quoted include must resolve beside its includer.
 - `include/fastfields/core/dlpack.h` is vendored upstream code: do not edit it,
  and it is skipped by `codespell` (see `.codespellrc`).
 

diff --git a/include/fastfields/api/checks.h b/include/fastfields/api/checks.h
@@ -1,8 +1,8 @@
 #ifndef FF_LIB_CHECKS
 #define FF_LIB_CHECKS
 #include <stdexcept>
-#include "fastfields/core/dlpack.h"
-#include "fastfields/core/defines.h"
+#include <fastfields/core/dlpack.h>
+#include <fastfields/core/defines.h>
 
 FF_NAMESPACE_BEGIN(FF_NS)
 

diff --git a/include/fastfields/api/cpu/distance.h b/include/fastfields/api/cpu/distance.h
@@ -1,6 +1,6 @@
 #ifndef FF_CPU_DISTANCE
 #define FF_CPU_DISTANCE
-#include "fastfields/core/dlpack.h"
+#include <fastfields/core/dlpack.h>
 #include <cstdint>
 
 namespace ff {

diff --git a/include/fastfields/api/cpu/posdef.h b/include/fastfields/api/cpu/posdef.h
@@ -1,6 +1,6 @@
 #ifndef FF_CPU_POSDEF
 #define FF_CPU_POSDEF
-#include "fastfields/core/dlpack.h"
+#include <fastfields/core/dlpack.h>
 #include <cstdint>
 
 namespace ff {

diff --git a/include/fastfields/api/cpu/pushpull.h b/include/fastfields/api/cpu/pushpull.h
@@ -1,6 +1,6 @@
 #ifndef FF_CPU_PUSHPULL
 #define FF_CPU_PUSHPULL
-#include "fastfields/core/dlpack.h"
+#include <fastfields/core/dlpack.h>
 #include <cstdint>
 
 namespace ff {

diff --git a/include/fastfields/api/cpu/pushpull_dispatch.h b/include/fastfields/api/cpu/pushpull_dispatch.h
@@ -16,12 +16,12 @@
  */
 #include <stdexcept>
 #include <cstdint>
-#include "fastfields/core/autocast.h"
-#include "fastfields/core/dispatch.h"
-#include "fastfields/core/dlpack.h"
-#include "fastfields/core/cuda_switch.h"
-#include "fastfields/impl/kernels/utils.h"
-#include "fastfields/impl/cpu/pushpull.h"
+#include <fastfields/core/autocast.h>
+#include <fastfields/core/dispatch.h>
+#include <fastfields/core/dlpack.h>
+#include <fastfields/core/cuda_switch.h>
+#include <fastfields/impl/kernels/utils.h>
+#include <fastfields/impl/cpu/pushpull.h>
 
 FF_NAMESPACE_BEGIN(FF_NS)
 FF_NAMESPACE_BEGIN(FF_DEVICE)

diff --git a/include/fastfields/api/cpu/reg_field.h b/include/fastfields/api/cpu/reg_field.h
@@ -1,6 +1,6 @@
 #ifndef FF_CPU_REG_FIELD
 #define FF_CPU_REG_FIELD
-#include "fastfields/core/dlpack.h"
+#include <fastfields/core/dlpack.h>
 #include <cstdint>
 
 namespace ff {

diff --git a/include/fastfields/api/cpu/reg_flow.h b/include/fastfields/api/cpu/reg_flow.h
@@ -1,6 +1,6 @@
 #ifndef FF_CPU_REG_FLOW
 #define FF_CPU_REG_FLOW
-#include "fastfields/core/dlpack.h"
+#include <fastfields/core/dlpack.h>
 #include <cstdint>
 
 namespace ff {

diff --git a/include/fastfields/api/cpu/resize.h b/include/fastfields/api/cpu/resize.h
@@ -1,6 +1,6 @@
 #ifndef FF_CPU_RESIZE
 #define FF_CPU_RESIZE
-#include "fastfields/core/dlpack.h"
+#include <fastfields/core/dlpack.h>
 #include <cstdint>
 
 namespace ff {

diff --git a/include/fastfields/api/cpu/restrict.h b/include/fastfields/api/cpu/restrict.h
@@ -1,6 +1,6 @@
 #ifndef FF_CPU_RESTRICT
 #define FF_CPU_RESTRICT
-#include "fastfields/core/dlpack.h"
+#include <fastfields/core/dlpack.h>
 #include <cstdint>
 
 namespace ff {

diff --git a/include/fastfields/api/cpu/solve_field.h b/include/fastfields/api/cpu/solve_field.h
@@ -1,6 +1,6 @@
 #ifndef FF_CPU_SOLVE_FIELD
 #define FF_CPU_SOLVE_FIELD
-#include "fastfields/core/dlpack.h"
+#include <fastfields/core/dlpack.h>
 #include <cstdint>
 
 namespace ff {

diff --git a/include/fastfields/api/cpu/splinc.h b/include/fastfields/api/cpu/splinc.h
@@ -1,6 +1,6 @@
 #ifndef FF_CPU_SPLINC
 #define FF_CPU_SPLINC
-#include "fastfields/core/dlpack.h"
+#include <fastfields/core/dlpack.h>
 #include <cstdint>
 
 namespace ff {

diff --git a/include/fastfields/api/cuda/distance.h b/include/fastfields/api/cuda/distance.h
@@ -1,6 +1,6 @@
 #ifndef FF_CUDA_DISTANCE
 #define FF_CUDA_DISTANCE
-#include "fastfields/core/dlpack.h"
+#include <fastfields/core/dlpack.h>
 #include <cstdint>
 
 namespace ff {

diff --git a/include/fastfields/api/cuda/posdef.h b/include/fastfields/api/cuda/posdef.h
@@ -1,6 +1,6 @@
 #ifndef FF_CUDA_POSDEF
 #define FF_CUDA_POSDEF
-#include "fastfields/core/dlpack.h"
+#include <fastfields/core/dlpack.h>
 #include <cstdint>
 
 namespace ff {

diff --git a/include/fastfields/api/cuda/pushpull.h b/include/fastfields/api/cuda/pushpull.h
@@ -1,6 +1,6 @@
 #ifndef FF_CUDA_PUSHPULL
 #define FF_CUDA_PUSHPULL
-#include "fastfields/core/dlpack.h"
+#include <fastfields/core/dlpack.h>
 #include <cstdint>
 
 namespace ff {

diff --git a/include/fastfields/api/cuda/pushpull_dispatch.h b/include/fastfields/api/cuda/pushpull_dispatch.h
@@ -16,12 +16,12 @@
  */
 #include <stdexcept>
 #include <cstdint>
-#include "fastfields/core/autocast.h"
-#include "fastfields/core/dispatch.h"
-#include "fastfields/core/dlpack.h"
-#include "fastfields/core/cuda_switch.h"
-#include "fastfields/impl/kernels/utils.h"
-#include "fastfields/impl/cuda/pushpull.h"
+#include <fastfields/core/autocast.h>
+#include <fastfields/core/dispatch.h>
+#include <fastfields/core/dlpack.h>
+#include <fastfields/core/cuda_switch.h>
+#include <fastfields/impl/kernels/utils.h>
+#include <fastfields/impl/cuda/pushpull.h>
 
 FF_NAMESPACE_BEGIN(FF_NS)
 FF_NAMESPACE_BEGIN(FF_DEVICE)

diff --git a/include/fastfields/api/cuda/reg_field.h b/include/fastfields/api/cuda/reg_field.h
@@ -1,6 +1,6 @@
 #ifndef FF_CUDA_REG_FIELD
 #define FF_CUDA_REG_FIELD
-#include "fastfields/core/dlpack.h"
+#include <fastfields/core/dlpack.h>
 #include <cstdint>
 
 namespace ff {

diff --git a/include/fastfields/api/cuda/reg_flow.h b/include/fastfields/api/cuda/reg_flow.h
@@ -1,6 +1,6 @@
 #ifndef FF_CUDA_REG_FLOW
 #define FF_CUDA_REG_FLOW
-#include "fastfields/core/dlpack.h"
+#include <fastfields/core/dlpack.h>
 #include <cstdint>
 
 namespace ff {

diff --git a/include/fastfields/api/cuda/resize.h b/include/fastfields/api/cuda/resize.h
@@ -1,6 +1,6 @@
 #ifndef FF_CUDA_RESIZE
 #define FF_CUDA_RESIZE
-#include "fastfields/core/dlpack.h"
+#include <fastfields/core/dlpack.h>
 #include <cstdint>
 
 namespace ff {

diff --git a/include/fastfields/api/cuda/restrict.h b/include/fastfields/api/cuda/restrict.h
@@ -1,6 +1,6 @@
 #ifndef FF_CUDA_RESTRICT
 #define FF_CUDA_RESTRICT
-#include "fastfields/core/dlpack.h"
+#include <fastfields/core/dlpack.h>
 #include <cstdint>
 
 namespace ff {

diff --git a/include/fastfields/api/cuda/splinc.h b/include/fastfields/api/cuda/splinc.h
@@ -1,6 +1,6 @@
 #ifndef FF_CUDA_SPLINC
 #define FF_CUDA_SPLINC
-#include "fastfields/core/dlpack.h"
+#include <fastfields/core/dlpack.h>
 #include <cstdint>
 
 namespace ff {

diff --git a/include/fastfields/api/cuda/stream.h b/include/fastfields/api/cuda/stream.h
@@ -16,7 +16,7 @@
  */
 
 #include <cstdint>
-#include "fastfields/core/cuda_switch.h"
+#include <fastfields/core/cuda_switch.h>
 
 FF_NAMESPACE_BEGIN(FF_NS)
 FF_NAMESPACE_BEGIN(FF_DEVICE)

diff --git a/include/fastfields/api/distance.h b/include/fastfields/api/distance.h
@@ -1,8 +1,8 @@
 #ifndef FF_LIB_DISTANCE
 #define FF_LIB_DISTANCE
-#include "fastfields/core/dlpack.h"
+#include <fastfields/core/dlpack.h>
 #include <cstdint>
-#include "fastfields/core/defines.h"
+#include <fastfields/core/defines.h>
 
 FF_NAMESPACE_BEGIN(FF_NS)
 

diff --git a/include/fastfields/api/posdef.h b/include/fastfields/api/posdef.h
@@ -1,8 +1,8 @@
 #ifndef FF_LIB_POSDEF
 #define FF_LIB_POSDEF
-#include "fastfields/core/dlpack.h"
+#include <fastfields/core/dlpack.h>
 #include <cstdint>
-#include "fastfields/core/defines.h"
+#include <fastfields/core/defines.h>
 
 FF_NAMESPACE_BEGIN(FF_NS)
 

diff --git a/include/fastfields/api/pushpull.h b/include/fastfields/api/pushpull.h
@@ -1,8 +1,8 @@
 #ifndef FF_LIB_PUSHPULL
 #define FF_LIB_PUSHPULL
-#include "fastfields/core/dlpack.h"
+#include <fastfields/core/dlpack.h>
 #include <cstdint>
-#include "fastfields/core/defines.h"
+#include <fastfields/core/defines.h>
 
 #ifndef FF_LIB_BOUND_SPLINE_T
 #define FF_LIB_BOUND_SPLINE_T

diff --git a/include/fastfields/api/reg_field.h b/include/fastfields/api/reg_field.h
@@ -1,8 +1,8 @@
 #ifndef FF_LIB_REG_FIELD
 #define FF_LIB_REG_FIELD
-#include "fastfields/core/dlpack.h"
+#include <fastfields/core/dlpack.h>
 #include <cstdint>
-#include "fastfields/core/defines.h"
+#include <fastfields/core/defines.h>
 
 #ifndef FF_LIB_BOUND_SPLINE_T
 #define FF_LIB_BOUND_SPLINE_T

diff --git a/include/fastfields/api/reg_flow.h b/include/fastfields/api/reg_flow.h
@@ -1,8 +1,8 @@
 #ifndef FF_LIB_REG_FLOW
 #define FF_LIB_REG_FLOW
-#include "fastfields/core/dlpack.h"
+#include <fastfields/core/dlpack.h>
 #include <cstdint>
-#include "fastfields/core/defines.h"
+#include <fastfields/core/defines.h>
 
 #ifndef FF_LIB_BOUND_SPLINE_T
 #define FF_LIB_BOUND_SPLINE_T

diff --git a/include/fastfields/api/resize.h b/include/fastfields/api/resize.h
@@ -1,8 +1,8 @@
 #ifndef FF_LIB_RESIZE
 #define FF_LIB_RESIZE
-#include "fastfields/core/dlpack.h"
+#include <fastfields/core/dlpack.h>
 #include <cstdint>
-#include "fastfields/core/defines.h"
+#include <fastfields/core/defines.h>
 
 #ifndef FF_LIB_BOUND_SPLINE_T
 #define FF_LIB_BOUND_SPLINE_T

diff --git a/include/fastfields/api/restrict.h b/include/fastfields/api/restrict.h
@@ -1,8 +1,8 @@
 #ifndef FF_LIB_RESTRICT
 #define FF_LIB_RESTRICT
-#include "fastfields/core/dlpack.h"
+#include <fastfields/core/dlpack.h>
 #include <cstdint>
-#include "fastfields/core/defines.h"
+#include <fastfields/core/defines.h>
 
 #ifndef FF_LIB_BOUND_SPLINE_T
 #define FF_LIB_BOUND_SPLINE_T

diff --git a/include/fastfields/api/solve_field.h b/include/fastfields/api/solve_field.h
@@ -1,7 +1,7 @@
 #ifndef FF_LIB_SOLVE_FIELD
 #define FF_LIB_SOLVE_FIELD
-#include "fastfields/core/dlpack.h"
-#include "fastfields/core/defines.h"
+#include <fastfields/core/dlpack.h>
+#include <fastfields/core/defines.h>
 
 #ifndef FF_LIB_BOUND_SPLINE_T
 #define FF_LIB_BOUND_SPLINE_T

diff --git a/include/fastfields/api/splinc.h b/include/fastfields/api/splinc.h
@@ -1,10 +1,10 @@
 #ifndef FF_LIB_SPLINC
 #define FF_LIB_SPLINC
-#include "fastfields/core/dlpack.h"
+#include <fastfields/core/dlpack.h>
 #include <cstdint>
 #include <stdexcept>
 #include <string>
-#include "fastfields/core/defines.h"
+#include <fastfields/core/defines.h>
 
 #ifndef FF_LIB_BOUND_SPLINE_T
 #define FF_LIB_BOUND_SPLINE_T

diff --git a/include/fastfields/core/autocast.h b/include/fastfields/core/autocast.h
@@ -3,8 +3,8 @@
 #define FF_AUTOCAST
 #include <cstddef>
 #include <cstdint>
-#include "fastfields/core/dlpack.h"
-#include "fastfields/core/cuda_switch.h"
+#include <fastfields/core/dlpack.h>
+#include <fastfields/core/cuda_switch.h>
 
 FF_NAMESPACE_BEGIN(FF_NS)
 FF_NAMESPACE_BEGIN(FF_DEVICE)

diff --git a/include/fastfields/core/cuda_switch.h b/include/fastfields/core/cuda_switch.h
@@ -49,6 +49,6 @@
 
 #endif
 
-#include "fastfields/core/defines.h"
+#include <fastfields/core/defines.h>
 
 #endif // FF_CUDA_SWITCH
diff --git a/include/fastfields/core/dispatch.h b/include/fastfields/core/dispatch.h
@@ -43,9 +43,9 @@
 #include <cstdint> // int32_t (the shape loops), int64_t
 #include <stdexcept> // std::invalid_argument
 #include <vector> // as_weights
-#include "fastfields/core/dlpack.h"
-#include "fastfields/core/defines.h" // FF_NAMESPACE_*
-#include "fastfields/core/autocast.h" // canUse32BitIndexMath
+#include <fastfields/core/dlpack.h>
+#include <fastfields/core/defines.h> // FF_NAMESPACE_*
+#include <fastfields/core/autocast.h> // canUse32BitIndexMath
 
 /***********************************************************************
  * POINTER MARSHALLING *

diff --git a/include/fastfields/impl/cpu/distance_euclidean.h b/include/fastfields/impl/cpu/distance_euclidean.h
@@ -1,10 +1,10 @@
 #ifndef FF_CPU_DISTANCE_EUCLIDEAN
 #define FF_CPU_DISTANCE_EUCLIDEAN
-#include "fastfields/core/cuda_switch.h"
-#include "fastfields/impl/kernels/distance.h"
-#include "fastfields/impl/kernels/batch.h"
-#include "fastfields/impl/kernels/parallel.h"
-#include "fastfields/impl/kernels/utils.h"
+#include <fastfields/core/cuda_switch.h>
+#include <fastfields/impl/kernels/distance.h>
+#include <fastfields/impl/kernels/batch.h>
+#include <fastfields/impl/kernels/parallel.h>
+#include <fastfields/impl/kernels/utils.h>
 
 FF_NAMESPACE_BEGIN(FF_NS)
 FF_NAMESPACE_BEGIN(FF_DEVICE)

diff --git a/include/fastfields/impl/cpu/distance_l1.h b/include/fastfields/impl/cpu/distance_l1.h
@@ -1,10 +1,10 @@
 #ifndef FF_CPU_DISTANCE_L1
 #define FF_CPU_DISTANCE_L1
-#include "fastfields/core/cuda_switch.h"
-#include "fastfields/impl/kernels/distance.h"
-#include "fastfields/impl/kernels/batch.h"
-#include "fastfields/impl/kernels/parallel.h"
-#include "fastfields/impl/kernels/utils.h"
+#include <fastfields/core/cuda_switch.h>
+#include <fastfields/impl/kernels/distance.h>
+#include <fastfields/impl/kernels/batch.h>
+#include <fastfields/impl/kernels/parallel.h>
+#include <fastfields/impl/kernels/utils.h>
 
 FF_NAMESPACE_BEGIN(FF_NS)
 FF_NAMESPACE_BEGIN(FF_DEVICE)

diff --git a/include/fastfields/impl/cpu/distance_mesh.h b/include/fastfields/impl/cpu/distance_mesh.h
@@ -1,10 +1,10 @@
 #ifndef FF_CPU_DISTANCE_MESH
 #define FF_CPU_DISTANCE_MESH
-#include "fastfields/core/cuda_switch.h"
-#include "fastfields/impl/kernels/distance.h"
-#include "fastfields/impl/kernels/distance/mesh_utils.h"
-#include "fastfields/impl/kernels/batch.h"
-#include "fastfields/impl/kernels/parallel.h"
+#include <fastfields/core/cuda_switch.h>
+#include <fastfields/impl/kernels/distance.h>
+#include <fastfields/impl/kernels/distance/mesh_utils.h>
+#include <fastfields/impl/kernels/batch.h>
+#include <fastfields/impl/kernels/parallel.h>
 
 FF_NAMESPACE_BEGIN(FF_NS)
 FF_NAMESPACE_BEGIN(FF_DEVICE)