HcalAlgos/src/ThirdOrderDelayODE.cc

0001 #include <cmath>
0002 #include <cassert>
0003 #include "FWCore/Utilities/interface/Exception.h"
0004
0005 #include "CalibCalorimetry/HcalAlgos/interface/ThirdOrderDelayODE.h"
0006
0007 void ThirdOrderDelayODE::calculate(const double tau,
0008                                    const double currentIn,
0009                                    double /* dIdt */,
0010                                    double /* d2Id2t */,
0011                                    const double* x,
0012                                    const unsigned lenX,
0013                                    const unsigned firstNode,
0014                                    double* derivative) const {
0015   // Check input sanity
0016   if (lenX < firstNode + 3U)
0017     throw cms::Exception("In ThirdOrderDelayODE::calculate: insufficient number of variables");
0018   if (tau <= 0.0)
0019     throw cms::Exception("In ThirdOrderDelayODE::calculate: delay time is not positive");
0020   assert(x);
0021   assert(derivative);
0022
0023   derivative[firstNode] = x[firstNode + 1];
0024   derivative[firstNode + 1] = x[firstNode + 2];
0025   derivative[firstNode + 2] =
0026       6.0 / a_ * (currentIn - x[firstNode] - c_ * tau * x[firstNode + 1] - b_ / 2.0 * tau * tau * x[firstNode + 2]) /
0027       tau / tau / tau;
0028 }
0029
0030 void ThirdOrderDelayODE::setParameters(const double* pars, const unsigned nPars) {
0031   assert(nPars == 3U);
0032   assert(pars);
0033   a_ = exp(pars[0]);
0034   b_ = exp(pars[1]);
0035   c_ = exp(pars[2]);
0036 }