BmnRun8HalfDM.h

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/*
    BM@N alignment routine
    BM@N experiment at NICA complex, JINR, 2025
 
    Department: Math & Soft Group of HEP lab
    Author:     Igor Polev, polev@jinr.int
 
    BmnRun8HalfDM class declaration
    Run8 full-granularity representation, single half of each station only
*/
 
#ifndef BMNRUN8HALFDM_H
#define BMNRUN8HALFDM_H
 
#include "BmnRun8DM.h"
 
#include <TString.h>
#include <numeric>
 
/*
 *  Common base for the fine-grained half-assembly models: same every-module
 *  scheme as BmnRun8DM, but only one half of every station is alignable
 *  (38 elements). Top elements carry the first half of module numbers, bottom
 *  elements the second half. Derived classes pick the kept half via
 *  KeepBottomHalf().
 *
 *  Hierarchical parametrization
 *  ----------------------------
 *  The half of a station is a rigid mechanical unit, so the model declares one
 *  composite node per station half on top of the 38 element-level nodes. Each
 *  composite therefore carries its own 6 rigid-body corrections, and every
 *  element carries a full set of its own within it - see BmnAlignHierarchy.
 *  Pivots are left to the default (centre of gravity of the owned elements,
 *  i.e. the beam axis at their mean z).
 */
 
class BmnRun8HalfDM : public BmnRun8DM
{
  protected:
    // selects which half of every station is alignable
    virtual Bool_t KeepBottomHalf() const noexcept = 0;
 
    // the bottom half starts where the station's own module count says it does
    virtual Int_t FirstModule(Int_t station) const noexcept override
    {
        return MOD_NUM_START + (KeepBottomHalf() ? StationModules(station) / 2 : 0);
    }
    // half of what the full model aligns in that station
    virtual Int_t StationAlignables(Int_t station) const noexcept override
    {
        return BmnRun8DM::StationAlignables(station) / 2;
    }
 
  public:
    virtual Bool_t IgnoreHit(Int_t CbmDetectorID) const noexcept override
    {
        const Int_t module{((CbmDetectorID >> 4) & 0xFFF) - MOD_NUM_START},
            station{((CbmDetectorID >> 16) & 0xFF) - STA_NUM_START}, half{StationModules(station) / 2};
        return KeepBottomHalf() ? module < half : module >= half;
    }
    virtual Bool_t IgnoresSome() const noexcept override { return kTRUE; }
 
    virtual std::vector<Composite> Composites() const override
    {
        // NextID() walks the stations in order and never revisits one, so the
        // elements of a station half occupy a contiguous index range
        std::vector<Composite> nodes;
        nodes.reserve(LastStation() - FirstStation() + 1);
        for (Int_t station = FirstStation(), leaf = 0; station <= LastStation(); station++) {
            Composite node;
            node.name = Form("STA%02d", station + STA_NUM_START);
            node.leaves.resize(StationAlignables(station));
            std::iota(node.leaves.begin(), node.leaves.end(), leaf);
            leaf += node.leaves.size();
            nodes.push_back(std::move(node));
        }
        return nodes;
    }
};
 
#endif   // BMNRUN8HALFDM_H