BmnAlignTestTask.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
 
    BmnAlignTestTask class declaration
    Synthetic alignment tasks with a known answer
*/
 
#ifndef BMNALIGNTESTTASK_H
#define BMNALIGNTESTTASK_H
 
#include "BmnAligner.h"
 
#include <TVector2.h>
 
/*
 *  Builds a dataset whose true misalignment is known, so that a solution can be
 *  compared against the answer instead of against itself.
 *
 *  Takes a loaded aligner, fits straight tracks to its real data, displaces the
 *  detector by a randomized solution, and writes out hits made by the
 *  measurement model of the displaced detector, plus the solution that produced
 *  them. The real hits are taken in the geometry of the aligner's last result,
 *  the nominal one if it has none.
 *
 *  The randomized solution is drawn from the aligner's presigmas, which are
 *  therefore the truth sigmas here, not the priors the task will be solved
 *  with. It obeys the aligner's constraints, so the alignment of the task must
 *  use the same constraints file. For a model
 *  with a target element the tracks that come from the vertex pass through it
 *  exactly, the others keep their own lines; the target sits at z0, the z where
 *  the real tracks meet the beam, which Make() measures and reports. See Make().
 *
 *  The aligner is left as it was found, except for the states of its vertex
 *  hits, which Make() tests (Align() tests them again anyway).
 *
 *  A consumer of BmnAligner, not part of it - production alignment never needs
 *  this, and the solver should not carry it.
 */
 
class BmnAlignTestTask
{
  public:
    // where the noise sigma of a synthetic hit comes from
    enum ENoise
    {
        kHitErrors,      // the error fields of its source hit
        kElementMeans,   // the mean hit error of its element in the source data
        kUserValues      // stdDevXY of Make(), the same for every hit
    };
 
    BmnAlignTestTask() = delete;
 
    static Bool_t Make(
        BmnAligner& aligner,
        const char* dataPath,        // .root file to write the synthetic hits into
        const char* solutionPath,    // .json file to write the truth solution into
        Double_t sigmaScale = 1.0,   // truth StdDev = presigma * sigmaScale; 0 for the nominal geometry
        ENoise noise = kHitErrors,
        const TVector2& stdDevXY = TVector2()   // kUserValues only; a zero component means no noise there
    );
};
 
#endif   // BMNALIGNTESTTASK_H