GPU: Add option to o2 propagator to optionally use GPU PolynomialField instead of normal o2 MagFieldFast

Author: davidrohr

Detectors/Base/CMakeLists.txt

@@ -16,7 +16,7 @@ o2_add_library(DetectorsBase
                        src/MatLayerCyl.cxx
                        src/MatLayerCylSet.cxx
                        src/Ray.cxx
-		       src/DCAFitter.cxx
+                       src/DCAFitter.cxx
                        src/BaseDPLDigitizer.cxx
                        src/CTFCoderBase.cxx
                PUBLIC_LINK_LIBRARIES FairRoot::Base
@@ -29,8 +29,10 @@ o2_add_library(DetectorsBase
                                      O2::Framework
                                      FairMQ::FairMQ
                                      O2::DataFormatsParameters
-				     O2::SimConfig
-                                     ROOT::VMC)
+                                     O2::SimConfig
+                                     ROOT::VMC
+               PRIVATE_INCLUDE_DIRECTORIES ${CMAKE_SOURCE_DIR}/GPU/GPUTracking/Merger # Must not link to avoid cyclic dependency
+                             )
 
 o2_target_root_dictionary(DetectorsBase
                           HEADERS include/DetectorsBase/Detector.h

Detectors/Base/include/DetectorsBase/Propagator.h

@@ -44,6 +44,11 @@ namespace field
 class MagFieldFast;
 }
 
+namespace gpu
+{
+class GPUTPCGMPolynomialField;
+}
+
 namespace base
 {
 class Propagator
@@ -104,6 +109,8 @@ class Propagator
 
   GPUd() void setMatLUT(const o2::base::MatLayerCylSet* lut) { mMatLUT = lut; }
   GPUd() const o2::base::MatLayerCylSet* getMatLUT() const { return mMatLUT; }
+  GPUd() void setGPUField(const o2::gpu::GPUTPCGMPolynomialField* field) { mGPUField = field; }
+  GPUd() const o2::gpu::GPUTPCGMPolynomialField* getGPUField() const { return mGPUField; }
 
 #ifndef GPUCA_GPUCODE
   static Propagator* Instance()
@@ -123,11 +130,13 @@ class Propagator
 #endif
 
   GPUd() MatBudget getMatBudget(MatCorrType corrType, const o2::math_utils::Point3D<float>& p0, const o2::math_utils::Point3D<float>& p1) const;
+  GPUd() void getFiedXYZ(const math_utils::Point3D<float> xyz, float* bxyz) const;
 
   const o2::field::MagFieldFast* mField = nullptr; ///< External fast field (barrel only for the moment)
   float mBz = 0;                                   // nominal field
 
-  const o2::base::MatLayerCylSet* mMatLUT = nullptr; // externally set LUT
+  const o2::base::MatLayerCylSet* mMatLUT = nullptr;           // externally set LUT
+  const o2::gpu::GPUTPCGMPolynomialField* mGPUField = nullptr; // externally set GPU Field
 
   ClassDef(Propagator, 0);
 };

Detectors/Base/src/Propagator.cxx

@@ -10,13 +10,17 @@
 
 #include "DetectorsBase/Propagator.h"
 #include "GPUCommonLogger.h"
-#include "Field/MagFieldFast.h"
+#include "GPUTPCGMPolynomialField.h"
 #include "MathUtils/Utils.h"
 #include "ReconstructionDataFormats/Vertex.h"
 
 using namespace o2::base;
 
-#ifndef GPUCA_STANDALONE
+#if !defined(GPUCA_GPUCODE)
+#include "Field/MagFieldFast.h" // Don't use this on the GPU
+#endif
+
+#if !defined(GPUCA_STANDALONE) && !defined(GPUCA_GPUCODE)
 #include "Field/MagneticField.h"
 #include "DataFormatsParameters/GRPObject.h"
 #include "DetectorsBase/GeometryManager.h"
@@ -125,7 +129,7 @@ GPUd() bool Propagator::PropagateToXBxByBz(o2::track::TrackParCov& track, float
     }
     auto x = track.getX() + step;
     auto xyz0 = track.getXYZGlo();
-    mField->Field(xyz0, &b[0]);
+    getFiedXYZ(xyz0, &b[0]);
 
     if (!track.propagateTo(x, b)) {
       return false;
@@ -184,7 +188,7 @@ GPUd() bool Propagator::PropagateToXBxByBz(o2::track::TrackPar& track, float xTo
     }
     auto x = track.getX() + step;
     auto xyz0 = track.getXYZGlo();
-    mField->Field(xyz0, &b[0]);
+    getFiedXYZ(xyz0, &b[0]);
 
     if (!track.propagateParamTo(x, b)) {
       return false;
@@ -516,3 +520,19 @@ GPUd() MatBudget Propagator::getMatBudget(Propagator::MatCorrType corrType, cons
 #endif
   return mMatLUT->getMatBudget(p0.X(), p0.Y(), p0.Z(), p1.X(), p1.Y(), p1.Z());
 }
+
+GPUd() void Propagator::getFiedXYZ(const math_utils::Point3D<float> xyz, float* bxyz) const
+{
+  if (mGPUField) {
+#if defined(GPUCA_GPUCODE_DEVICE) && defined(GPUCA_HAS_GLOBAL_SYMBOL_CONSTANT_MEM)
+    const auto* f = &GPUCA_CONSMEM.param.polynomialField; // Access directly from constant memory on GPU (copied here to avoid complicated header dependencies)
+#else
+    const auto* f = mGPUField;
+#endif
+    f->GetField(xyz.X(), xyz.Y(), xyz.Z(), bxyz);
+  } else {
+#ifndef GPUCA_GPUCODE
+    mField->Field(xyz, bxyz); // Must not call the host-only function in GPU compilation
+#endif
+  }
+}

GPU/GPUTracking/Merger/GPUTPCGMPolynomialField.h

@@ -14,7 +14,7 @@
 #ifndef GPUTPCGMPOLYNOMIALFIELD_H
 #define GPUTPCGMPOLYNOMIALFIELD_H
 
-#include "GPUTPCDef.h"
+#include "GPUCommonDef.h"
 
 namespace GPUCA_NAMESPACE
 {