DigitizedClusterGT.h

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#ifndef DataFormats_L1TCalorimeterPhase2_DigitizedClusterGT_h
#define DataFormats_L1TCalorimeterPhase2_DigitizedClusterGT_h

#include <ap_int.h>
#include <vector>

namespace l1tp2 {

  class DigitizedClusterGT {
  private:
    // Data
    unsigned long long int clusterData;

    // Constants
    static constexpr float LSB_PT = 0.03125;                 // 0.03125 GeV
    static constexpr unsigned int n_bits_eta_pi = 12;        // 12 bits corresponds to pi in eta
    static constexpr unsigned int n_bits_phi_pi = 12;        // 12 bits corresponds to pi in phi
    static constexpr unsigned int n_bits_pt = 16;            // 12 bits allocated for pt
    static constexpr unsigned int n_bits_unused_start = 44;  // unused bits start at bit number 44

    float LSB_ETA = (M_PI / std::pow(2, n_bits_eta_pi));
    float LSB_PHI = (M_PI / std::pow(2, n_bits_phi_pi));

    // Private member functions to perform digitization
    ap_uint<1> digitizeIsValid(bool isValid) { return (ap_uint<1>)isValid; }

    ap_uint<16> digitizePt(float pt_f) {
      float maxPt_f = (std::pow(2, n_bits_pt) - 1) * LSB_PT;
      // If pT exceeds the maximum, saturate the value
      if (pt_f >= maxPt_f) {
        return (ap_uint<16>)0xFFFF;
      }
      return (ap_uint<16>)(pt_f / LSB_PT);
    }

    // Use two's complements representation
    ap_int<13> digitizePhi(float phi_f) {
      ap_int<13> phi_digitized = (phi_f / LSB_PHI);
      return phi_digitized;
    }

    // Use two's complements representation
    ap_int<14> digitizeEta(float eta_f) {
      ap_int<14> eta_digitized = (eta_f / LSB_ETA);
      return eta_digitized;
    }

  public:
    DigitizedClusterGT() { clusterData = 0x0; }

    DigitizedClusterGT(ap_uint<64> data) { clusterData = data; }

    // Constructor from digitized inputs
    DigitizedClusterGT(ap_uint<1> isValid, ap_uint<16> pt, ap_int<13> phi, ap_int<14> eta, bool fullyDigitizedInputs) {
      (void)fullyDigitizedInputs;
      clusterData =
          ((ap_uint<64>)isValid) | (((ap_uint<64>)pt) << 1) | (((ap_uint<64>)phi) << 17) | (((ap_uint<64>)eta) << 30);
    }

    // Constructor from float inputs that will perform digitization
    DigitizedClusterGT(bool isValid, float pt_f, float phi_f, float eta_f) {
      // N.b.: For eta/phi, after shifting the bits to the correct place and casting to ap_uint<64>,
      // we have an additional bit mask
      // e.g. 0x3FFE0000 for phi. This mask is all zero's except for 1 in the phi bits (bits 17 through 29):
      // bit mask = 0x3FFE0000 = 0b111111111111100000000000000000
      // Applying the "and" of this bitmask, avoids bogus 1's in the case where phi is negative

      clusterData = ((ap_uint<64>)digitizeIsValid(isValid)) | ((ap_uint<64>)digitizePt(pt_f) << 1) |
                    (((ap_uint<64>)digitizePhi(phi_f) << 17) &
                     0x3FFE0000) |  // 0x3FFE0000 is all zero's except the phi bits (bits 17 through 29)
                    (((ap_uint<64>)digitizeEta(eta_f) << 30) &
                     0xFFFC0000000);  // 0xFFFC0000000 is all zero's except the eta bits (bits 30 through 32)
    }

    ap_uint<64> data() const { return clusterData; }

    // Other getters
    float ptLSB() const { return LSB_PT; }
    float phiLSB() const { return LSB_PHI; }
    float etaLSB() const { return LSB_ETA; }
    ap_uint<1> isValid() const { return (clusterData & 0x1); }
    ap_uint<16> pt() const { return ((clusterData >> 1) & 0xFFFF); }   // 16 1's = 0xFFFF
    ap_int<13> phi() const { return ((clusterData >> 17) & 0x1FFF); }  // (thirteen 1's)= 0x1FFF
    ap_int<14> eta() const { return ((clusterData >> 30) & 0x3FFF); }  // (fourteen 1's) = 0x3FFF

    float ptFloat() const { return (pt() * ptLSB()); }
    float realPhi() const {  // convert from signed int to float
      return (phi() * phiLSB());
    }
    float realEta() const {  // convert from signed int to float
      return (eta() * etaLSB());
    }
    const int unusedBitsStart() const { return n_bits_unused_start; }  // unused bits start at bit 44

    // Other checks
    bool passNullBitsCheck(void) const { return ((data() >> unusedBitsStart()) == 0x0); }
  };

  // Collection typedef
  typedef std::vector<l1tp2::DigitizedClusterGT> DigitizedClusterGTCollection;

}  // namespace l1tp2

#endif