Use bfield interpolation rather than NN (acts-project#617)

I believe the trilinear interpolation should be used instead of the nearest neighbor (NN) method. The interpolation is what Geant4 and Acts are using with RKN method - If we want to use the NN method, we need to prove that it doesn't harm the performanc first.

Author: beomki-yeo

.github/workflows/builds.yml

@@ -73,7 +73,7 @@ jobs:
     # Set the path to the test data files
     env:
       DETRAY_DATA_DIRECTORY: ${{ github.workspace }}/data/
-      DETRAY_BFIELD_FILE: ${{ github.workspace }}/data/odd-bfield_v0_8_0.cvf
+      DETRAY_BFIELD_FILE: ${{ github.workspace }}/data/odd-bfield_v0_9_0.cvf
 
     # The build/test steps to execute.
     steps:

.gitlab-ci.yml

@@ -28,7 +28,7 @@ build_cuda:
 test_cuda:
   variables:
     DETRAY_DATA_DIRECTORY: src/data/
-    DETRAY_BFIELD_FILE: $CI_PROJECT_DIR/src/data/odd-bfield_v0_8_0.cvf
+    DETRAY_BFIELD_FILE: $CI_PROJECT_DIR/src/data/odd-bfield_v0_9_0.cvf
   stage: test
   tags: [docker-gpu-nvidia]
   image: ghcr.io/acts-project/ubuntu2004_cuda:v30

data/detray_data_get_files.sh

@@ -27,7 +27,7 @@ usage() {
 }
 
 # Default script arguments.
-DETRAY_DATA_NAME=${DETRAY_DATA_NAME:-"detray-data-v1"}
+DETRAY_DATA_NAME=${DETRAY_DATA_NAME:-"detray-data-v2"}
 DETRAY_WEB_DIRECTORY=${DETRAY_WEB_DIRECTORY:-"https://acts.web.cern.ch/traccc/data"}
 DETRAY_DATA_DIRECTORY=${DETRAY_DATA_DIRECTORY:-$(cd $(dirname "${BASH_SOURCE[0]}") && pwd)}
 DETRAY_CMAKE_EXECUTABLE=${DETRAY_CMAKE_EXECUTABLE:-cmake}

extern/covfie/CMakeLists.txt

@@ -18,7 +18,7 @@ message( STATUS "Fetching covfie as part of the Detray project" )
 
 # Declare where to get covfie from.
 set( DETRAY_COVFIE_SOURCE
-   "URL;https://github.com/acts-project/covfie/archive/refs/tags/v0.8.1.tar.gz;URL_MD5;0b4dc9624533d1ed4ea7a763da47f07e"
+   "URL;https://github.com/acts-project/covfie/archive/refs/tags/v0.9.0.tar.gz;URL_MD5;b310712c6dd1acc8104c734086f40fc0"
    CACHE STRING "Source for covfie, when built as part of this project" )
 mark_as_advanced( DETRAY_COVFIE_SOURCE )
 FetchContent_Declare( covfie ${DETRAY_COVFIE_SOURCE} )

tests/unit_tests/device/cuda/propagator_cuda_kernel.hpp

@@ -24,10 +24,10 @@ namespace detray {
 namespace bfield::cuda {
 
 // Inhomogeneous field (cuda)
-using inhom_bknd_t = covfie::backend::affine<
-    covfie::backend::nearest_neighbour<covfie::backend::strided<
-        covfie::vector::ulong3, covfie::backend::cuda_device_array<
-                                    covfie::vector::vector_d<scalar, 3>>>>>;
+using inhom_bknd_t = covfie::backend::affine<covfie::backend::linear<
+    covfie::backend::strided<covfie::vector::vector_d<std::size_t, 3>,
+                             covfie::backend::cuda_device_array<
+                                 covfie::vector::vector_d<scalar, 3>>>>>;
 
 }  // namespace bfield::cuda
 

tutorials/src/device/cuda/propagation.hpp

@@ -31,9 +31,9 @@ namespace detray::tutorial {
 namespace bfield::cuda {
 
 // Inhomogeneous field (cuda)
-using inhom_bknd_t = covfie::backend::affine<
-    covfie::backend::nearest_neighbour<covfie::backend::strided<
-        covfie::vector::ulong3,
+using inhom_bknd_t =
+    covfie::backend::affine<covfie::backend::linear<covfie::backend::strided<
+        covfie::vector::vector_d<std::size_t, 3>,
         covfie::backend::cuda_device_array<
             covfie::vector::vector_d<detray::scalar, 3>>>>>;
 

utils/include/detray/detectors/bfield.hpp

@@ -14,9 +14,11 @@
 // Covfie include(s)
 #include <covfie/core/backend/primitive/constant.hpp>
 #include <covfie/core/backend/transformer/affine.hpp>
+#include <covfie/core/backend/transformer/linear.hpp>
 #include <covfie/core/backend/transformer/nearest_neighbour.hpp>
 #include <covfie/core/backend/transformer/strided.hpp>
 #include <covfie/core/field.hpp>
+#include <covfie/core/vector.hpp>
 
 namespace detray::bfield {
 
@@ -28,7 +30,13 @@ using const_bknd_t =
 using const_field_t = covfie::field<const_bknd_t>;
 
 /// Inhomogeneous field (host)
-using inhom_bknd_t = covfie::backend::affine<
+using inhom_bknd_t =
+    covfie::backend::affine<covfie::backend::linear<covfie::backend::strided<
+        covfie::vector::vector_d<std::size_t, 3>,
+        covfie::backend::array<covfie::vector::vector_d<detray::scalar, 3>>>>>;
+
+/// Inhomogeneous field with nearest neighbor (host)
+using inhom_bknd_nn_t = covfie::backend::affine<
     covfie::backend::nearest_neighbour<covfie::backend::strided<
         covfie::vector::ulong3,
         covfie::backend::array<covfie::vector::vector_d<detray::scalar, 3>>>>>;