code to refit tracks with different correction maps e.g.

Detectors/TPC/workflow/CMakeLists.txt

@@ -62,6 +62,12 @@ o2_add_library(TPCWorkflowGUI
                                      O2::TPCMonitor
            )
 
+o2_add_library(TPCWorkflowStudies
+               SOURCES src/TPCRefitter.cxx
+               TARGETVARNAME targetName
+               PUBLIC_LINK_LIBRARIES O2::TPCWorkflow
+                                     O2::GlobalTrackingWorkflow
+           )
 
 o2_add_executable(chunkeddigit-merger
         COMPONENT_NAME tpc
@@ -283,4 +289,9 @@ o2_add_executable(calibration-workflow
                                         O2::DataFormatsCalibration
                                         O2::CCDB)
 
+o2_add_executable(refitter
+                  SOURCES src/tpc-refitter-workflow.cxx
+                  COMPONENT_NAME tpc
+                  PUBLIC_LINK_LIBRARIES O2::TPCWorkflowStudies)
+
 add_subdirectory(readers)

Detectors/TPC/workflow/include/TPCWorkflow/TPCRefitter.h

@@ -0,0 +1,34 @@
+// Copyright 2019-2020 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.
+
+#ifndef O2_TPC_DATA_FILTER_H
+#define O2_TPC_DATA_FILTER_H
+
+#include "ReconstructionDataFormats/GlobalTrackID.h"
+#include "Framework/Task.h"
+#include "Framework/DataProcessorSpec.h"
+#include "ReconstructionDataFormats/Track.h"
+#include "MathUtils/detail/Bracket.h"
+#include "DataFormatsTPC/ClusterNative.h"
+
+namespace o2::tpc
+{
+struct CorrectionMapsLoaderGloOpts;
+}
+
+namespace o2::trackstudy
+{
+/// create a processor spec
+o2::framework::DataProcessorSpec getTPCRefitterSpec(o2::dataformats::GlobalTrackID::mask_t srcTracks, o2::dataformats::GlobalTrackID::mask_t srcClus, bool useMC, const o2::tpc::CorrectionMapsLoaderGloOpts& sclOpts);
+
+} // namespace o2::trackstudy
+
+#endif