AliceO2Group · shahor02 · Jun 23, 2026
@@ -11,9 +11,12 @@
 
 o2_add_library(DataFormatsCalibration
                SOURCES src/MeanVertexObject.cxx
+               SOURCES src/MeanVertexBiasParam.cxx
                PUBLIC_LINK_LIBRARIES O2::ReconstructionDataFormats
-                                     O2::Framework)
+                                     O2::Framework
+                                     O2::CommonUtils)
 
 o2_target_root_dictionary(DataFormatsCalibration
-                          HEADERS include/DataFormatsCalibration/MeanVertexObject.h)
+                          HEADERS include/DataFormatsCalibration/MeanVertexObject.h
+                                  include/DataFormatsCalibration/MeanVertexBiasParam.h)
 
@@ -0,0 +1,38 @@
+// Copyright 2019-2026 CERN and copyright holders of ALICE O2.
+// See https://alice-o2.web.cern.ch/copyright for details of the copyright holders.
+// All rights not expressly granted are reserved.
+//
+// This software is distributed under the terms of the GNU General Public
+// License v3 (GPL Version 3), copied verbatim in the file "COPYING".
+//
+// In applying this license CERN does not waive the privileges and immunities
+// granted to it by virtue of its status as an Intergovernmental Organization
+// or submit itself to any jurisdiction.
+
+/// \author ruben.shahoyan@cern.ch
+
+/// parameters to bias precalibrated mean vertex, e.g after the alignment shift
+
+#ifndef ALICEO2_MEANVERTEX_BIAS_PARAM_H
+#define ALICEO2_MEANVERTEX_BIAS_PARAM_H
+
+#include "CommonUtils/ConfigurableParam.h"
+#include "CommonUtils/ConfigurableParamHelper.h"
+
+namespace o2
+{
+namespace dataformats
+{
+
+struct MeanVertexBiasParam : public o2::conf::ConfigurableParamHelper<MeanVertexBiasParam> {
+  float xyz[3] = {};  // position bias
+  float slopeX = 0.f; // x slope bias
+  float slopeY = 0.f; // y slope bias
+
+  O2ParamDef(MeanVertexBiasParam, "mvbias");
+};
+
+} // namespace dataformats
+} // end namespace o2
+
+#endif
@@ -15,31 +15,45 @@
 #include <array>
 #include "Framework/Logger.h"
 #include "ReconstructionDataFormats/Vertex.h"
+#include "DataFormatsCalibration/MeanVertexBiasParam.h"
 
 namespace o2
 {
 namespace dataformats
 {
 class MeanVertexObject : public VertexBase
 {
-
  public:
   MeanVertexObject(float x, float y, float z, float sigmax, float sigmay, float sigmaz, float slopeX, float slopeY)
   {
+    if (!gMVBias) {
+      checkExternalBias();
+    }
     setXYZ(x, y, z);
     setSigma({sigmax, sigmay, sigmaz});
     mSlopeX = slopeX;
     mSlopeY = slopeY;
   }
+
   MeanVertexObject(std::array<float, 3> pos, std::array<float, 3> sigma, float slopeX, float slopeY)
   {
+    if (!gMVBias) {
+      checkExternalBias();
+    }
     math_utils::Point3D<float> p(pos[0], pos[1], pos[2]);
     setPos(p);
     setSigma(sigma);
     mSlopeX = slopeX;
     mSlopeY = slopeY;
   }
-  MeanVertexObject() = default;
+
+  MeanVertexObject()
+  {
+    if (!gMVBias) {
+      checkExternalBias();
+    }
+  }
+
   ~MeanVertexObject() = default;
   MeanVertexObject(const MeanVertexObject& other) = default;
   MeanVertexObject(MeanVertexObject&& other) = default;
@@ -57,14 +71,28 @@ class MeanVertexObject : public VertexBase
   void setSlopeX(float val) { mSlopeX = val; }
   void setSlopeY(float val) { mSlopeY = val; }
 
-  math_utils::Point3D<float>& getPos() { return getXYZ(); }
+  // getting the cartesian coordinates and errors
+  float getX() const { return VertexBase::getX() + gMVBias->xyz[0]; }
+  float getY() const
+  {
+    return VertexBase::getY() + gMVBias->xyz[1];
+    ;
+  }
+  float getZ() const
+  {
+    return VertexBase::getZ() + gMVBias->xyz[2];
+    ;
+  }
+  float getR() const { return gpu::CAMath::Hypot(getX(), getY()); }
+
+  math_utils::Point3D<float> getXYZ() const { return {getX(), getY(), getZ()}; }
   math_utils::Point3D<float> getPos() const { return getXYZ(); }
 
-  float getSlopeX() const { return mSlopeX; }
-  float getSlopeY() const { return mSlopeY; }
+  float getSlopeX() const { return mSlopeX + gMVBias->slopeX; }
+  float getSlopeY() const { return mSlopeY + gMVBias->slopeY; }
 
-  float getXAtZ(float z) const { return getX() + mSlopeX * (z - getZ()); }
-  float getYAtZ(float z) const { return getY() + mSlopeY * (z - getZ()); }
+  float getXAtZ(float z) const { return getX() + getSlopeX() * (z - getZ()); }
+  float getYAtZ(float z) const { return getY() + getSlopeY() * (z - getZ()); }
 
   void print() const;
   std::string asString() const;
@@ -82,21 +110,24 @@ class MeanVertexObject : public VertexBase
 
   void setMeanXYVertexAtZ(VertexBase& v, float z) const
   {
-    float dz = z - getZ();
-    v.setX(getX() + mSlopeX * dz);
-    v.setY(getY() + mSlopeY * dz);
+    v.setX(getXAtZ(z));
+    v.setY(getYAtZ(z));
     v.setZ(z);
   }
 
-  const VertexBase& getMeanVertex() const
+  const VertexBase getMeanVertex() const
   {
-    return (const VertexBase&)(*this);
+    return getMeanVertex(getZ());
   }
 
+  static void checkExternalBias();
+
  private:
   float mSlopeX{0.f}; // slope of x = f(z)
   float mSlopeY{0.f}; // slope of y = f(z)
 
+  static const MeanVertexBiasParam* gMVBias;
+
   ClassDefNV(MeanVertexObject, 2);
 };
 

@@ -15,6 +15,8 @@
 #pragma link off all classes;
 #pragma link off all functions;
 
-#pragma link C++ struct o2::dataformats::MeanVertexObject + ;
+#pragma link C++ class o2::dataformats::MeanVertexObject + ;
+#pragma link C++ class o2::dataformats::MeanVertexBiasParam + ;
+#pragma link C++ class o2::conf::ConfigurableParamHelper < o2::dataformats::MeanVertexBiasParam> + ;
 
 #endif
@@ -0,0 +1,18 @@
+// Copyright 2019-2026 CERN and copyright holders of ALICE O2.
+// See https://alice-o2.web.cern.ch/copyright for details of the copyright holders.
+// All rights not expressly granted are reserved.
+//
+// This software is distributed under the terms of the GNU General Public
+// License v3 (GPL Version 3), copied verbatim in the file "COPYING".
+//
+// In applying this license CERN does not waive the privileges and immunities
+// granted to it by virtue of its status as an Intergovernmental Organization
+// or submit itself to any jurisdiction.
+
+/// \author ruben.shahoyan@cern.ch
+
+/// parameters to bias precalibrated mean vertex, e.g after the alignment shift
+
+#include "DataFormatsCalibration/MeanVertexBiasParam.h"
+
+O2ParamImpl(o2::dataformats::MeanVertexBiasParam);
@@ -12,10 +12,13 @@
 #include "DataFormatsCalibration/MeanVertexObject.h"
 #include "TRandom.h"
 
+#include <cstdlib>
+
 namespace o2
 {
 namespace dataformats
 {
+const MeanVertexBiasParam* MeanVertexObject::gMVBias = nullptr;
 
 void MeanVertexObject::set(int icoord, float val)
 {
@@ -45,7 +48,9 @@ void MeanVertexObject::setSigma(int icoord, float val)
 
 std::string MeanVertexObject::asString() const
 {
-  return VertexBase::asString() + fmt::format(" Slopes {{{:+.4e},{:+.4e}}}", mSlopeX, mSlopeY);
+  return fmt::format("Vtx {{{:+.4e},{:+.4e},{:+.4e}}} Cov.:{{{{{:.3e}..}},{{{:.3e},{:.3e}..}},{{{:.3e},{:.3e},{:.3e}}}}} | bias: XYZ: {:.4f},{:.4f},{:.4f} SlopeXY: {:.3e},{:.3e}",
+                     getX(), getY(), getZ(), mCov[0], mCov[1], mCov[2], mCov[3], mCov[4], mCov[5],
+                     gMVBias->xyz[0], gMVBias->xyz[1], gMVBias->xyz[2], gMVBias->slopeX, gMVBias->slopeY);
 }
 
 std::ostream& operator<<(std::ostream& os, const o2::dataformats::MeanVertexObject& o)
@@ -70,5 +75,16 @@ math_utils::Point3D<float> MeanVertexObject::sample() const
   return math_utils::Point3D<float>(x, y, z);
 }
 
+void MeanVertexObject::checkExternalBias()
+{
+  // posibility to globally bias all data members with the proper env.var
+  if (const auto* biasString = std::getenv("O2_DPL_MVBIAS"); biasString && *biasString) {
+    o2::conf::ConfigurableParam::updateFromString(biasString);
+  }
+  gMVBias = &MeanVertexBiasParam::Instance();
+  LOGP(info, "Mean vertex is biased by: XYZ: {:.4f},{:.4f},{:.4f} SlopeXY: {:.3e},{:.3e}",
+       gMVBias->xyz[0], gMVBias->xyz[1], gMVBias->xyz[2], gMVBias->slopeX, gMVBias->slopeY);
+}
+
 } // namespace dataformats
 } // namespace o2