FPGATrackSimFunctions.h

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/*
  Copyright (C) 2002-2021 CERN for the benefit of the ATLAS collaboration
*/
 
/*
 * FPGATrackSimFunctions.h
 *
 * Declares several generic utility functions.
 */
 
#ifndef FPGATrackSimFUNCTIONS_H
#define FPGATrackSimFUNCTIONS_H
 
 
#include <TString.h>
#include <TObjArray.h>
#include <TH1.h>
#include <TObjString.h>
#include <TTreeReader.h>
#include <TTreeReaderValue.h>
 
#include "FPGATrackSimObjects/FPGATrackSimTypes.h"
#include "FPGATrackSimObjects/FPGATrackSimHit.h"
 
 
#include <cmath>
#include <vector>
#include <sstream>
 
 
 
/*****************************************************************************/
/* Bit Manipulations and Arithmetic
 *
 * Avoid using templates because right-shifts will not work correctly if
 * accidentally called using a signed type.
 */
/*****************************************************************************/
 
// Returns a list of words, each with one bit set for each bit set in x
// Sorted by LSB to MSB.
inline std::vector<uint32_t> splitSetBits32(uint32_t x)
{
    std::vector<uint32_t> out;
    uint32_t setbit = 0x1;
    while (setbit != 0 && x != 0)
    {
        if (x & 1) out.push_back(setbit);
        x = x >> 1;
        setbit = setbit << 1;
    }
    return out;
}
 
 
// Returns the first set bit of x, starting from the LSB (0 indexed).
// Returns -1 if x == 0.
inline int firstSetBit32(uint32_t x)
{
    unsigned bit = 0;
    while (x)
    {
        if (x & 1) return bit;
        x >>= 1;
        bit++;
    }
    return -1;
}
 
 
// Divide x/y, rounding up. x,y can not be 0.
inline unsigned divUp(unsigned x, unsigned y)
{
    // return (x + y - 1) / y; runs risk of overflow
    return 1 + ((x - 1) / y);
}
 
 
// Gray code: https://en.wikipedia.org/wiki/Gray_code#Converting_to_and_from_Gray_code
inline uint32_t binaryToGray(uint32_t num)
{
    return num ^ (num >> 1);
}
 
 
inline uint32_t grayToBinary32(uint32_t num)
{
    num = num ^ (num >> 16);
    num = num ^ (num >> 8);
    num = num ^ (num >> 4);
    num = num ^ (num >> 2);
    num = num ^ (num >> 1);
    return num;
}
 
 
 
/*****************************************************************************/
/* Vectors and Indexing                                                      */
/*****************************************************************************/

std::vector<std::vector<int>> getComboIndices(std::vector<size_t> const & sizes);
 
 
 
/*****************************************************************************/
/* RMS95 Value Calculation                                                   */
/*****************************************************************************/

double rms95(TH1 const * h);
 
// The Hough transform magnetic field correction.
// Apply correction due to B != 2T everywhere. This correction should be ADDED to track phi.
double fieldCorrection(unsigned region, double qoverpt, double r);
 
std::vector<float> computeIdealCoords(const FPGATrackSimHit &hit, const double hough_x, const double hough_y, const double target_r, const bool doDeltaGPhis, const TrackCorrType trackCorrType);
 
#endif // FPGATrackSimFUNCTIONS_H