ReconstructionDataFormats: express the SMatrix aliases in GPUdoubleCalc

MatrixDSym5 and MatrixD5 were kept off Metal because SMatrix<double> cannot be
named there, which left the track-to-track chi2 and update out of the device
build. Spelling them in GPUdoubleCalc brings them back: it is double on every
other backend and on the host, so the aliases and everything using them are
unchanged there, and on Metal they become the compensated two-float type that
the rest of this file already uses.

The two remaining explicit doubles go the same way, and the SMatrix written out
in full is just MatrixD5.

Author: ktf

DataFormats/Reconstruction/include/ReconstructionDataFormats/TrackParametrizationWithError.h

@@ -17,6 +17,7 @@
 #ifndef INCLUDE_RECONSTRUCTIONDATAFORMATS_TRACKPARAMETRIZATIONWITHERROR_H_
 #define INCLUDE_RECONSTRUCTIONDATAFORMATS_TRACKPARAMETRIZATIONWITHERROR_H_
 
+#include "GPUCommonDouble.h"
 #include "ReconstructionDataFormats/TrackParametrization.h"
 #include <MathUtils/Cartesian.h>
 
@@ -41,10 +42,8 @@ class TrackParametrizationWithError : public TrackParametrization<value_T>
 #endif
 
   using covMat_t = std::array<value_t, kCovMatSize>;
-#ifndef __METAL__
-  using MatrixDSym5 = o2::math_utils::SMatrix<double, kNParams, kNParams, o2::math_utils::MatRepSym<double, kNParams>>;
-  using MatrixD5 = o2::math_utils::SMatrix<double, kNParams, kNParams, o2::math_utils::MatRepStd<double, kNParams, kNParams>>;
-#endif
+  using MatrixDSym5 = o2::math_utils::SMatrix<o2::gpu::GPUdoubleCalc, kNParams, kNParams, o2::math_utils::MatRepSym<o2::gpu::GPUdoubleCalc, kNParams>>;
+  using MatrixD5 = o2::math_utils::SMatrix<o2::gpu::GPUdoubleCalc, kNParams, kNParams, o2::math_utils::MatRepStd<o2::gpu::GPUdoubleCalc, kNParams, kNParams>>;
 
   GPUhd() TrackParametrizationWithError();
   GPUd() TrackParametrizationWithError(value_t x, value_t alpha, const params_t& par, const covMat_t& cov, int charge = 1, const PID pid = PID::Pion);
@@ -113,18 +112,12 @@ class TrackParametrizationWithError : public TrackParametrization<value_T>
   template <typename T>
   GPUd() value_t getPredictedChi2Quiet(const BaseCluster<T>& p) const;
 
-#ifndef __METAL__
   GPUd() void buildCombinedCovMatrix(const TrackParametrizationWithError& rhs, MatrixDSym5& cov) const;
-#endif
-#ifndef __METAL__
   GPUd() value_t getPredictedChi2(const TrackParametrizationWithError& rhs, MatrixDSym5& covToSet) const;
-#endif
   GPUd() value_t getPredictedChi2(const TrackParametrizationWithError& rhs) const;
   GPUd() value_t getPredictedChi2Fast(const TrackParametrizationWithError& rhs) const;
   GPUd() value_t getPredictedChi2Quiet(const TrackParametrizationWithError& rhs) const;
-#ifndef __METAL__
   GPUd() bool update(const TrackParametrizationWithError& rhs, const MatrixDSym5& covInv);
-#endif
   GPUd() bool update(const TrackParametrizationWithError& rhs);
 
   GPUd() bool update(const dim2_t& p, const dim3_t& cov);

DataFormats/Reconstruction/src/TrackParametrizationWithError.cxx

@@ -1174,7 +1174,7 @@ GPUd() auto TrackParametrizationWithError<value_T>::getPredictedChi2Fast(const T
   // chi2 = d^T C^-1 d = sum_i y_i^2 / D_i with y from the forward substitution L y = d
   GPUdoubleCalc chi2 = 0., y[kNParams];
   for (int i = 0; i < kNParams; i++) {
-    GPUdoubleCalc s = double(this->getParam(i)) - double(rhs.getParam(i));
+    GPUdoubleCalc s = GPUdoubleCalc(this->getParam(i)) - GPUdoubleCalc(rhs.getParam(i));
     for (int k = 0; k < i; k++) {
       s -= lmat[i][k] * y[k];
     }
@@ -1287,7 +1287,7 @@ GPUd() bool TrackParametrizationWithError<value_T>::update(const TrackParametriz
   }
 
   // updated covariance: Cov0 = Cov0 - K*Cov0
-  matK *= o2::math_utils::SMatrix<double, kNParams, kNParams, o2::math_utils::MatRepStd<double, kNParams>>(matC0);
+  matK *= MatrixD5(matC0);
   mC[kSigY2] -= matK(kY, kY);
   mC[kSigZY] -= matK(kZ, kY);
   mC[kSigZ2] -= matK(kZ, kZ);