GetAllEi.cpp

//----------------------------------------------------------------------
// Includes
//----------------------------------------------------------------------
#include <boost/format.hpp>
#include <boost/algorithm/string.hpp>
#include <string>

#include "MantidAlgorithms/GetAllEi.h"
#include "MantidKernel/BoundedValidator.h"
#include "MantidKernel/FilteredTimeSeriesProperty.h"
#include "MantidKernel/EnabledWhenProperty.h"
#include "MantidKernel/UnitFactory.h"
#include "MantidKernel/Unit.h"
#include "MantidKernel/VectorHelper.h"
#include "MantidDataObjects/TableWorkspace.h"

namespace Mantid {
namespace Algorithms {

DECLARE_ALGORITHM(GetAllEi)

/// Empty default constructor
GetAllEi::GetAllEi()
    : Algorithm(), m_FilterLogName(""), m_FilterWithDerivative(true),
      // minimal resolution for all instruments
      m_min_Eresolution(0.08),
      // half maximal resolution for LET
      m_max_Eresolution(0.5e-3), m_peakEnergyRatio2reject(0.1), m_phase(0),
      m_chopper() {}

/// Initialization method.
void GetAllEi::init() {

  declareProperty(new API::WorkspaceProperty<API::MatrixWorkspace>(
                      "Workspace", "", Kernel::Direction::Input),
                  "The input workspace containing the monitor's spectra "
                  "measured after the last chopper");
  auto nonNegative = boost::make_shared<Kernel::BoundedValidator<int>>();
  nonNegative->setLower(0);

  declareProperty(
      "Monitor1SpecID", EMPTY_INT(), nonNegative,
      "The workspace index (ID) of the spectra, containing first monitor's"
      " signal to analyze.");
  declareProperty(
      "Monitor2SpecID", EMPTY_INT(), nonNegative,
      "The workspace index (ID) of the spectra, containing second monitor's"
      " signal to analyze.");

  declareProperty("ChopperSpeedLog", "Defined in IDF",
                  "Name of the instrument log, "
                  "containing chopper angular velocity. If 'Defined in IDF' "
                  "option is specified, "
                  "the log name is obtained from the IDF");
  declareProperty(
      "ChopperDelayLog", "Defined in IDF",
      "Name of the instrument log, "
      "containing chopper delay time or chopper phase v.r.t. the pulse time. "
      "If 'Defined in IDF'  option is specified, "
      "the log name is obtained from IDF");
  declareProperty(
      "FilterBaseLog", "Defined in IDF",
      "Name of the instrument log, "
      "with positive values indicating that instrument is running\n "
      "and 0 or negative that it is not.\n"
      "The log is used to identify time interval to evaluate"
      " chopper speed and chopper delay which matter.\n"
      "If such log is not present, average log values are calculated "
      "within experiment start&end time range.");
  declareProperty(
      "FilterWithDerivative", true,
      "Use derivative of 'FilterBaseLog' "
      "rather then log values itself to filter invalid time intervals.\n"
      "Invalid values are then the "
      "values where the derivative of the log turns zero.\n"
      "E.g. the 'proton_chage' log grows for each frame "
      "when instrument is counting and is constant otherwise.");
  setPropertySettings(
      "FilterWithDerivative",
      new Kernel::EnabledWhenProperty("FilterBaseLog",
                                      Kernel::ePropertyCriterion::IS_EQUAL_TO,
                                      "Defined in IDF"));

  auto maxInRange = boost::make_shared<Kernel::BoundedValidator<double>>();
  maxInRange->setLower(1.e-6);
  maxInRange->setUpper(0.1);

  declareProperty("MaxInstrResolution", 0.0005, maxInRange,
                  "The maximal energy resolution possible for an "
                  "instrument at working energies (full width at half "
                  "maximum). \nPeaks, sharper then "
                  "this width are rejected. Accepted limits are: 1e^(-6)-0.1");

  auto minInRange = boost::make_shared<Kernel::BoundedValidator<double>>();
  minInRange->setLower(0.001);
  minInRange->setUpper(0.5);
  declareProperty(
      "MinInstrResolution", 0.08, minInRange,
      "The minimal energy resolution possible for an "
      "instrument at working energies (full width at half maximum).\n"
      "Peaks broader then this width are rejected. Accepted limits are: "
      "0.001-0.5");

  auto peakInRange = boost::make_shared<Kernel::BoundedValidator<double>>();
  peakInRange->setLower(0.0);
  minInRange->setUpper(1.);
  declareProperty(
      "PeaksRatioToReject", 0.1, peakInRange,
      "Ratio of a peak energy to the maximal energy among all peaks. "
      "If the ratio is lower then the value specified here, "
      "peak is treated as insignificant and rejected.\n"
      "Accepted limits are:0.0 (All accepted) to 1 -- only one peak \n"
      "(or peaks with max and equal intensity) are accepted.");
  declareProperty(
      "IgnoreSecondMonitor", false,
      "Usually peaks are analyzed and accepted "
      "only if identified on both monitors. If this property is set to true, "
      "only first monitor peaks are analyzed.\n"
      "This is debugging option as getEi has to use both monitors.");

  declareProperty(
      new API::WorkspaceProperty<API::Workspace>("OutputWorkspace", "",
                                                 Kernel::Direction::Output),
      "Name of the output matrix workspace, containing single spectra with"
      " monitor peaks energies\n"
      "together with total intensity within each peak.");
}
/**Simple template function to remove invalid data from vector
*@param guessValid -- boolean vector of indicating if each particular guess is
*valid
*@param guess      -- vector guess values at input and values with removing
*                     invalid parameters at output
*/
template <class T>
void removeInvalidValues(const std::vector<bool> &guessValid,
                         std::vector<T> &guess) {
  std::vector<T> new_guess;
  new_guess.reserve(guess.size());

  for (size_t i = 0; i < guessValid.size(); i++) {
    if (guessValid[i]) {
      new_guess.push_back(guess[i]);
    }
  }
  new_guess.swap(guess);
};
/**Internal class to contain peak information */
struct peakKeeper {
  double position;
  double height;
  double sigma;
  double energy;

  peakKeeper(double pos, double heigh, double sig)
      : position(pos), height(heigh), sigma(sig) {
    this->energy = std::sqrt(2 * M_PI) * height * sigma;
  }
  // to sort peaks
  bool operator<(const peakKeeper &str) const { return (energy > str.energy); }
};

struct peakKeeper2 {
  double left_rng;
  double right_rng;
  peakKeeper2(){};
  peakKeeper2(double left, double right) : left_rng(left), right_rng(right) {}
};

/** Executes the algorithm -- found all existing monitor peaks. */
void GetAllEi::exec() {
  // Get pointers to the workspace, parameter map and table
  API::MatrixWorkspace_sptr inputWS = getProperty("Workspace");
  m_min_Eresolution = getProperty("MinInstrResolution");
  m_max_Eresolution = getProperty("MaxInstrResolution");
  m_peakEnergyRatio2reject = getProperty("PeaksRatioToReject");

  ////---> recalculate chopper delay to monitor position:
  auto pInstrument = inputWS->getInstrument();
  // auto lastChopPositionComponent =
  // pInstrument->getComponentByName("chopper-position");
  // auto chopPoint1 = pInstrument->getChopperPoint(0); ->TODO: BUG! this
  // operation loses parameters map.
  m_chopper = pInstrument->getComponentByName("chopper-position");
  if (!m_chopper)
    throw std::runtime_error("Instrument " + pInstrument->getName() +
                             " does not have 'chopper-position' component");

  auto phase = m_chopper->getNumberParameter("initial_phase");

  if (phase.size() == 0) {
    throw std::runtime_error("Can not find initial_phase parameter"
                             " attached to the chopper-position component");
  }
  if (phase.size() > 1) {
    throw std::runtime_error(
        "Can not deal with multiple phases for initial_phase"
        " parameter attached to the chopper-position component");
  }
  m_phase = phase[0];
  std::string filterBase = getProperty("FilterBaseLog");
  if (boost::iequals(filterBase, "Defined in IDF")) {
    m_FilterLogName = m_chopper->getStringParameter("FilterBaseLog")[0];
    m_FilterWithDerivative =
        m_chopper->getBoolParameter("filter_with_derivative")[0];
  } else {
    m_FilterLogName = filterBase;
    m_FilterWithDerivative = getProperty("FilterWithDerivative");
  }
  try {
    auto pTimeSeries = dynamic_cast<Kernel::TimeSeriesProperty<double> *>(
        inputWS->run().getProperty(m_FilterLogName));
  } catch (std::runtime_error &) {
    g_log.warning() << " Can not retrieve (double) filtering log: " +
                           m_FilterLogName + " from current workspace\n"
                                             " Using total experiment range to "
                                             "find logs averages for chopper "
                                             "parameters\n";
    m_FilterLogName = "";
    m_FilterWithDerivative = false;
  }

  // auto chopPoint1  = pInstrument->getComponentByName("fermi-chopper");
  // auto par = chopPoint1->getDoubleParameter("Delay (us)");
  double chopSpeed, chopDelay;
  findChopSpeedAndDelay(inputWS, chopSpeed, chopDelay);
  g_log.debug() << boost::str(
      boost::format("*Identified avrg ChopSpeed: %8.2f and Delay: %8.2f\n") %
      chopSpeed % chopDelay);

  auto moderator = pInstrument->getSource();
  double chopDistance = m_chopper->getDistance(
      *moderator); // location[0].distance(moderator->getPos());
  double velocity = chopDistance / chopDelay;

  // build workspace to find monitor's peaks
  size_t det1WSIndex;
  auto monitorWS = buildWorkspaceToFit(inputWS, det1WSIndex);

  // recalculate delay time from chopper position to monitor position
  auto detector1 = inputWS->getDetector(det1WSIndex);
  double mon1Distance = detector1->getDistance(*moderator);
  double TOF0 = mon1Distance / velocity;

  //--->> below is reserved until full chopper's implementation is available;
  // auto nChoppers = pInstrument->getNumberOfChopperPoints();
  // get last chopper.
  /*
  if( nChoppers==0)throw std::runtime_error("Instrument does not have any
  choppers defined");

  auto lastChopper = pInstrument->getChopperPoint(nChoppers-1);
  ///<---------------------------------------------------
  */
  auto baseSpectrum = inputWS->getSpectrum(det1WSIndex);
  std::pair<double, double> TOF_range = baseSpectrum->getXDataRange();

  double Period =
      (0.5 * 1.e+6) / chopSpeed; // 0.5 because some choppers open twice.
  // Would be nice to have it 1 or 0.5 depending on chopper type, but
  // it looks like not enough information on what chopper is available on ws;
  std::vector<double> guess_opening;
  this->findGuessOpeningTimes(TOF_range, TOF0, Period, guess_opening);
  if (guess_opening.size() == 0) {
    throw std::runtime_error(
        "Can not find any chopper opening time within TOF range: " +
        std::to_string(TOF_range.first) + ':' +
        std::to_string(TOF_range.second));
  } else {
    g_log.debug() << "*Found : " << guess_opening.size()
                  << " chopper prospective opening within time frame: "
                  << TOF_range.first << " to: " << TOF_range.second
                  << std::endl;
    g_log.debug() << " Timings are:\n";
    for (size_t i = 0; i < guess_opening.size(); i++) {
      g_log.debug() << boost::str(boost::format(" %8.2f; ") % guess_opening[i]);
    }
    g_log.debug() << std::endl;
  }
  std::pair<double, double> Mon1_Erange =
      monitorWS->getSpectrum(0)->getXDataRange();
  std::pair<double, double> Mon2_Erange =
      monitorWS->getSpectrum(1)->getXDataRange();
  double eMin = std::max(Mon1_Erange.first, Mon2_Erange.first);
  double eMax = std::min(Mon1_Erange.second, Mon2_Erange.second);
  g_log.debug() << boost::str(
      boost::format(
          "Monitors record data in energy range Emin=%8.2f; Emax=%8.2f\n") %
      eMin % eMax);

  // convert to energy
  std::vector<double> guess_ei;
  guess_ei.reserve(guess_opening.size());
  double unused(0.0);
  auto destUnit = Kernel::UnitFactory::Instance().create("Energy");
  destUnit->initialize(mon1Distance, 0., 0.,
                       static_cast<int>(Kernel::DeltaEMode::Elastic), 0.,
                       unused);
  for (size_t i = 0; i < guess_opening.size(); i++) {
    double eGuess = destUnit->singleFromTOF(guess_opening[i]);
    if (eGuess > eMin && eGuess < eMax) {
      guess_ei.push_back(eGuess);
    }
  }
  g_log.debug() << "*From all chopper opening only: " +
                       std::to_string(guess_ei.size()) +
                       " fell within both monitor's recording energy range\n";
  g_log.debug() << " Guess Energies are:\n";
  for (size_t i = 0; i < guess_ei.size(); i++) {
    g_log.debug() << boost::str(boost::format(" %8.2f; ") % guess_ei[i]);
  }
  g_log.debug() << std::endl;

  std::sort(guess_ei.begin(), guess_ei.end());

  std::vector<size_t> irange_min, irange_max;
  std::vector<bool> guessValid;
  // preprocess first monitors peaks;
  g_log.debug() << "*Looking for real energy peaks on first monitor\n";
  findBinRanges(monitorWS->readX(0), monitorWS->readY(0), guess_ei,
                this->m_min_Eresolution / (2 * std::sqrt(2 * std::log(2.))),
                irange_min, irange_max, guessValid);

  // remove invalid guess values
  removeInvalidValues<double>(guessValid, guess_ei);

  // preprocess second monitors peaks
  std::vector<size_t> irange1_min, irange1_max;
  if (!this->getProperty("IgnoreSecondMonitor")) {
    g_log.debug() << "*Looking for real energy peaks on second monitor\n";
    findBinRanges(monitorWS->readX(1), monitorWS->readY(1), guess_ei,
                  this->m_min_Eresolution / (2 * std::sqrt(2 * std::log(2.))),
                  irange1_min, irange1_max, guessValid);
    removeInvalidValues<double>(guessValid, guess_ei);
    removeInvalidValues<size_t>(guessValid, irange_min);
    removeInvalidValues<size_t>(guessValid, irange_max);
  } else {
    // this is wrong but will not be used anyway
    // (except formally looping through vector)
    irange1_min.assign(irange_min.begin(), irange_min.end());
    irange1_max.assign(irange_max.begin(), irange_max.end());
  }
  g_log.debug()
      << "*Identified: " + std::to_string(guess_ei.size()) +
             " peaks with sufficient signal around guess chopper opening\n";

  std::vector<peakKeeper> peaks;

  double maxPeakEnergy(0);
  std::vector<size_t> monsRangeMin(2), monsRangeMax(2);
  for (size_t i = 0; i < guess_ei.size(); i++) {
    monsRangeMin[0] = irange_min[i];
    monsRangeMax[0] = irange_max[i];
    monsRangeMin[1] = irange1_min[i];
    monsRangeMax[1] = irange1_max[i];

    double energy, height, twoSigma;
    bool found = findMonitorPeak(monitorWS, guess_ei[i], monsRangeMin,
                                 monsRangeMax, energy, height, twoSigma);
    if (found) {
      peaks.push_back(peakKeeper(energy, height, 0.5 * twoSigma));
      if (peaks.back().energy > maxPeakEnergy)
        maxPeakEnergy = peaks.back().energy;
    }
  }
  monitorWS.reset();

  size_t nPeaks = peaks.size();
  if (nPeaks == 0) {
    throw std::runtime_error("Can not identify any energy peaks");
  }
  // sort peaks and remove invalid one
  guessValid.resize(nPeaks);
  bool needsRemoval(false);
  for (size_t i = 0; i < nPeaks; i++) {
    peaks[i].energy /= maxPeakEnergy;
    if (peaks[i].energy < m_peakEnergyRatio2reject) {
      guessValid[i] = false;
      g_log.debug() << "*Rejecting peak at Ei=" +
                           std::to_string(peaks[i].position) +
                           " as its total energy lower then the threshold\n";
      needsRemoval = true;
    } else {
      guessValid[i] = true;
    }
  }
  if (needsRemoval)
    removeInvalidValues<peakKeeper>(guessValid, peaks);
  nPeaks = peaks.size();
  // sort by energy decreasing -- see class definition
  std::sort(peaks.begin(), peaks.end());

  // finalize output
  auto result_ws = API::WorkspaceFactory::Instance().create("Workspace2D", 1,
                                                            nPeaks, nPeaks);

  MantidVec peaks_positions;
  MantidVec &Signal = result_ws->dataY(0);
  MantidVec &Error = result_ws->dataE(0);
  for (size_t i = 0; i < nPeaks; i++) {
    peaks_positions.push_back(peaks[i].position);
    Signal[i] = peaks[i].height;
    Error[i] = peaks[i].sigma;
  }
  result_ws->setX(0, peaks_positions);

  setProperty("OutputWorkspace", result_ws);
}

/**Get energy of monitor peak if one is present*/
bool GetAllEi::findMonitorPeak(const API::MatrixWorkspace_sptr &inputWS,
                               double Ei,
                               const std::vector<size_t> &monsRangeMin,
                               const std::vector<size_t> &monsRangeMax,
                               double &position, double &height,
                               double &twoSigma) {
  // calculate sigma from half-width parameters
  double maxSigma = Ei * m_min_Eresolution / (2 * std::sqrt(2 * std::log(2.)));
  double minSigma = Ei * m_max_Eresolution / (2 * std::sqrt(2 * std::log(2.)));

  /**Lambda to identify guess values for a peak at given index
  and set up these parameters as input for fitting algorithm   */
  auto peakGuess = [&](size_t index, double &peakPos, double &peakHeight,
                       double &peakTwoSigma) {

    double sMin(std::numeric_limits<double>::max());
    double sMax(-sMin);
    double xOfMax, dXmax;
    double ncMax(0), Intensity(0);

    auto X = inputWS->readX(index);
    auto S = inputWS->readY(index);
    size_t ind_min = monsRangeMin[index];
    size_t ind_max = monsRangeMax[index];
    // interval too small -- not interested in a peak there
    if (std::fabs(double(ind_max - ind_min)) < 5)
      return false;

    double xMin = X[ind_min];
    double xMax = X[ind_max];

    for (size_t i = ind_min; i < ind_max; i++) {
      double dX = X[i + 1] - X[i];
      double signal = S[i] / dX;
      if (signal < sMin)
        sMin = signal;
      if (signal > sMax) {
        sMax = signal;
        dXmax = dX;
        xOfMax = X[i];
      }
      Intensity += S[i];
    }
    // monitor peak should not have just two counts in it.
    if (sMax * dXmax <= 2)
      return false;
    //
    size_t SearchAreaSize = ind_max - ind_min;

    double SmoothRange = 2 * maxSigma;

    std::vector<double> SAvrg, binsAvrg;
    Kernel::VectorHelper::smoothInRange(S, SAvrg, SmoothRange, &X, ind_min,
                                        ind_max, &binsAvrg);

    double realPeakPos; // this position is less shifted due to the skew in
                        // averaging formula
    bool foundRealPeakPos(false);
    std::vector<double> der1Avrg, der2Avrg, peaks, hillsPos, SAvrg1, binsAvrg1;
    size_t nPeaks =
        calcDerivativeAndCountZeros(binsAvrg, SAvrg, der1Avrg, peaks);
    size_t nHills =
        calcDerivativeAndCountZeros(binsAvrg, der1Avrg, der2Avrg, hillsPos);
    size_t nPrevHills = 2 * nHills;
    if (nPeaks == 1) {
      foundRealPeakPos = true;
      realPeakPos = peaks[0];
    }

    size_t ic(0), stay_still_count(0);
    bool iterations_fail(false);
    while ((nPeaks > 1 || nHills > 2) && (!iterations_fail)) {
      Kernel::VectorHelper::smoothInRange(SAvrg, SAvrg1, SmoothRange, &binsAvrg,
                                          0, ind_max - ind_min, &binsAvrg1);
      nPrevHills = nHills;

      nPeaks = calcDerivativeAndCountZeros(binsAvrg1, SAvrg1, der1Avrg, peaks);
      nHills =
          calcDerivativeAndCountZeros(binsAvrg1, der1Avrg, der2Avrg, hillsPos);
      SAvrg.swap(SAvrg1);
      binsAvrg.swap(binsAvrg1);
      if (nPeaks == 1 && !foundRealPeakPos) { // fix first peak position found
        foundRealPeakPos = true;              // as averaging shift peaks on
        realPeakPos = peaks[0];               // irregular grid.
      }
      ic++;
      if (nPrevHills <= nHills) {
        stay_still_count++;
      } else {
        stay_still_count = 0;
      }
      if (ic > 50 || stay_still_count > 3)
        iterations_fail = true;
    }
    if (iterations_fail) {
      g_log.information() << "*No peak search convergence after " +
                                 std::to_string(ic) +
                                 " smoothing iterations at still_count: " +
                                 std::to_string(stay_still_count) +
                                 " Wrong energy or noisy peak at Ei=" +
                                 std::to_string(Ei) << std::endl;
    }
    g_log.debug() << "*Performed: " + std::to_string(ic) +
                         " averages for spectra " + std::to_string(index) +
                         " at energy: " + std::to_string(Ei) +
                         "\n and found: " + std::to_string(nPeaks) +
                         "peaks and " + std::to_string(nHills) + " hills\n";
    if (nPeaks != 1) {
      g_log.debug() << "*Peak rejected as n-peaks !=1 after averaging\n";
      return false;
    }

    peakPos = peaks[0];
    if (nHills > 2) {
      size_t peakIndex = Kernel::VectorHelper::getBinIndex(hillsPos, peaks[0]);
      peakTwoSigma = hillsPos[peakIndex + 1] - hillsPos[peakIndex];
    } else {
      if (hillsPos.size() == 2) {
        peakTwoSigma = hillsPos[1] - hillsPos[0];
      } else {
        g_log.debug() << "*Peak rejected as averaging gives: " +
                             std::to_string(nPeaks) + " peaks and " +
                             std::to_string(nHills) + " heals\n";

        return false;
      }
    }
    // assuming that averaging conserves intensity and removing linear
    // background:
    peakHeight = Intensity / (0.5 * std::sqrt(2. * M_PI) * peakTwoSigma) - sMin;
    peakPos = realPeakPos;

    return true;
  };
  //--------------------------------------------------------------------
  double peak1Pos, peak1TwoSigma, peak1Height;
  if (!peakGuess(0, peak1Pos, peak1Height, peak1TwoSigma))
    return false;
  if (0.25 * peak1TwoSigma > maxSigma || peak1TwoSigma < minSigma) {
    g_log.debug() << "*Rejecting due to width: Peak at mon1 Ei=" +
                         std::to_string(peak1Pos) + " with Height:" +
                         std::to_string(peak1Height) + " and 2*Sigma: " +
                         std::to_string(peak1TwoSigma) << std::endl;
    return false;
  }

  if (!this->getProperty("IgnoreSecondMonitor")) {
    double peak2Pos, peak2TwoSigma, peak2Height;
    if (!peakGuess(1, peak2Pos, peak2Height, peak2TwoSigma))
      return false;
    // Let's not check anything except peak position for monitor2, as
    // its intensity may be very low for some instruments.
    // if(0.25*peak2TwoSigma>maxSigma||peak2TwoSigma<minSigma)return false;

    // peak in first and second monitors are too far from each other. May be the
    // instrument
    // is ill-calibrated but GetEi will probably not find this peak anyway.
    if (std::fabs(peak1Pos - peak2Pos) >
        0.25 * (peak1TwoSigma + peak2TwoSigma)) {
      g_log.debug()
          << "*Rejecting due to displacement between Peak at mon1: Ei=" +
                 std::to_string(peak1Pos) + " with Height:" +
                 std::to_string(peak1Height) + " and 2*Sigma: " +
                 std::to_string(peak1TwoSigma) + "\n and Peak at mon2: Ei= " +
                 std::to_string(peak2Pos) + "and height: " +
                 std::to_string(peak1Height) << std::endl;

      return false;
    }
  }

  position = peak1Pos;
  twoSigma = peak1TwoSigma;
  height = peak1Height;

  return true;
}

/**Bare-bone function to calculate numerical derivative, and estimate number of
zeros
* this derivative has. No checks are performed for simplicity,
* so data have to be correct form at input.
*@param bins -- vector of bin boundaries.
*@param signal  -- vector of signal size of bins.size()-1
*@param deriv   -- output vector of numerical derivative
*@param zeros   -- coordinates of found zeros

*@return -- number of zeros, the derivative has in the interval provided.
*/
size_t GetAllEi::calcDerivativeAndCountZeros(const std::vector<double> &bins,
                                             const std::vector<double> &signal,
                                             std::vector<double> &deriv,
                                             std::vector<double> &zeros) {
  size_t nPoints = signal.size();
  deriv.resize(nPoints);
  zeros.resize(0);

  std::list<double> funVal, binVal;
  double bin0 = bins[1] - bins[0];
  double f0 = signal[0] / bin0;
  double bin1 = bins[2] - bins[1];
  double f1 = signal[1] / bin1;

  size_t nZeros(0);
  int prevSign = (f1 >= 0 ? 1 : -1);
  /**Estimate if sign have changed from its previous value*/
  auto signChanged = [&](double x) {
    int curSign = (x >= 0 ? 1 : -1);
    bool changed = curSign != prevSign;
    prevSign = curSign;
    return changed;
  };

  funVal.push_front(f1);
  binVal.push_front(bin1);
  deriv[0] = 2 * (f1 - f0) / (bin0 + bin1);
  for (size_t i = 1; i < nPoints - 1; i++) {
    bin1 = (bins[i + 2] - bins[i + 1]);
    f1 = signal[i + 1] / bin1;
    deriv[i] = (f1 - f0) / (bins[i + 1] - bins[i] + 0.5 * (bin1 + bin0));
    f0 = funVal.back();
    bin0 = binVal.back();
    funVal.pop_back();
    binVal.pop_back();
    funVal.push_front(f1);
    binVal.push_front(bin1);

    if (signChanged(deriv[i])) {
      nZeros++;
      zeros.push_back(0.5 * (bins[i + 1] + bins[i]));
    }
  }
  deriv[nPoints - 1] = 2 * (f1 - f0) / (bin1 + bin0);
  if (signChanged(deriv[nPoints - 1])) {
    zeros.push_back(bins[nPoints - 1]);
    nZeros++;
  }

  return nZeros;
}

/**Find indexes of each expected peak intervals from monotonous array of ranges.
@param eBins   -- bin ranges to look through
@param guess_energies -- vector of guess energies to look for
@param irangeMin  -- start indexes of energy intervals in the guess_energies
vector.
@param irangeMax  -- final indexes of energy intervals in the guess_energies
vector.
@param guessValid -- boolean vector, which specifies if guess energies are valid
*/
void GetAllEi::findBinRanges(const MantidVec &eBins, const MantidVec &signal,
                             const std::vector<double> &guess_energy,
                             double Eresolution, std::vector<size_t> &irangeMin,
                             std::vector<size_t> &irangeMax,
                             std::vector<bool> &guessValid) {

  size_t nBins = eBins.size();
  guessValid.resize(guess_energy.size());
  // get bin range corresponding to the energy range
  auto getBinRange =
      [&](double eMin, double eMax, size_t &index_min, size_t &index_max) {
        if (eMin <= eBins[0]) {
          index_min = 0;
        } else {
          index_min = Kernel::VectorHelper::getBinIndex(eBins, eMin);
        }

        if (eMax >= eBins[nBins - 1]) {
          index_max = nBins - 1;
        } else {
          index_max = Kernel::VectorHelper::getBinIndex(eBins, eMax) + 1;
          if (index_max >= nBins)
            index_max = nBins - 1; // last bin range anyway. Should not happen
        }
      };
  // refine bin range. May need better procedure for this.
  auto refineEGuess = [&](double &eGuess, size_t index_min, size_t index_max) {
    size_t ind_Emax = index_min;
    double SMax(0);
    for (size_t i = index_min; i < index_max; i++) {
      double dX = eBins[i + 1] - eBins[i];
      double sig = signal[i] / dX;
      if (sig > SMax) {
        SMax = sig;
        ind_Emax = i;
      }
    }
    if (ind_Emax == index_min || ind_Emax == index_max) {
      g_log.debug() << "*Incorrect guess energy: " << std::to_string(eGuess)
                    << " no energy peak found in 4*Sigma range\n";
      return false;
    }
    eGuess = 0.5 * (eBins[ind_Emax] + eBins[ind_Emax + 1]);
    return true;
  };

  // Do the job
  size_t ind_min, ind_max;
  irangeMin.resize(0);
  irangeMax.resize(0);

  // identify guess bin ranges
  std::vector<peakKeeper2> guess_peak(guess_energy.size());
  for (size_t nGuess = 0; nGuess < guess_energy.size(); nGuess++) {
    double eGuess = guess_energy[nGuess];
    getBinRange(eGuess * (1 - 4 * Eresolution), eGuess * (1 + 4 * Eresolution),
                ind_min, ind_max);
    guess_peak[nGuess] = peakKeeper2(eBins[ind_min], eBins[ind_max]);
  }
  // verify that the ranges not intercept and refine interceptions
  for (size_t i = 1; i < guess_energy.size(); i++) {
    if (guess_peak[i - 1].right_rng > guess_peak[i].left_rng) {
      double mid_pnt =
          0.5 * (guess_peak[i - 1].right_rng + guess_peak[i].left_rng);
      guess_peak[i - 1].right_rng = mid_pnt;
      guess_peak[i].left_rng = mid_pnt;
    }
  }
  // identify final bin ranges
  for (size_t nGuess = 0; nGuess < guess_energy.size(); nGuess++) {

    double eGuess = guess_energy[nGuess];
    getBinRange(guess_peak[nGuess].left_rng, guess_peak[nGuess].right_rng,
                ind_min, ind_max);

    if (refineEGuess(eGuess, ind_min, ind_max)) {

      getBinRange(
          std::max(guess_peak[nGuess].left_rng, eGuess * (1 - 3 * Eresolution)),
          std::max(guess_peak[nGuess].right_rng,
                   eGuess * (1 + 3 * Eresolution)),
          ind_min, ind_max);
      irangeMin.push_back(ind_min);
      irangeMax.push_back(ind_max);
      guessValid[nGuess] = true;
    } else {
      guessValid[nGuess] = false;
    }
  }
  // if array decreasing rather then increasing, indexes behave differently.
  // Will it still work?
  if (irangeMax.size() > 0) {
    if (irangeMax[0] < irangeMin[0]) {
      irangeMax.swap(irangeMin);
    }
  }
}

/**Build 2-spectra workspace in units of energy, used as source
*to identify actual monitors spectra
*@param inputWS shared pointer to initial workspace
*@param wsIndex0 -- returns workspace index for first detector.
*@return shared pointer to intermediate workspace, in units of energy
*        used to fit monitor's spectra.
*/
API::MatrixWorkspace_sptr
GetAllEi::buildWorkspaceToFit(const API::MatrixWorkspace_sptr &inputWS,
                              size_t &wsIndex0) {

  // at this stage all properties are validated so its safe to access them
  // without
  // additional checks.
  specid_t specNum1 = getProperty("Monitor1SpecID");
  wsIndex0 = inputWS->getIndexFromSpectrumNumber(specNum1);
  specid_t specNum2 = getProperty("Monitor2SpecID");
  size_t wsIndex1 = inputWS->getIndexFromSpectrumNumber(specNum2);
  auto pSpectr1 = inputWS->getSpectrum(wsIndex0);
  auto pSpectr2 = inputWS->getSpectrum(wsIndex1);
  // assuming equally binned ws.
  // auto bins       = inputWS->dataX(wsIndex0);
  auto bins = pSpectr1->dataX();
  size_t XLength = bins.size();
  size_t YLength = inputWS->dataY(wsIndex0).size();
  auto working_ws =
      API::WorkspaceFactory::Instance().create(inputWS, 2, XLength, YLength);
  // copy data --> very bad as implicitly assigns pointer
  // to bins array and bins array have to exist out of this routine
  // scope.
  // This does not matter in this case as below we convert units
  // which should decouple cow_pointer but very scary operation in
  // general.
  working_ws->setX(0, bins);
  working_ws->setX(1, bins);
  MantidVec &Signal1 = working_ws->dataY(0);
  MantidVec &Error1 = working_ws->dataE(0);
  MantidVec &Signal2 = working_ws->dataY(1);
  MantidVec &Error2 = working_ws->dataE(1);
  for (size_t i = 0; i < YLength; i++) {
    Signal1[i] = inputWS->dataY(wsIndex0)[i];
    Error1[i] = inputWS->dataE(wsIndex0)[i];
    Signal2[i] = inputWS->dataY(wsIndex1)[i];
    Error2[i] = inputWS->dataE(wsIndex1)[i];
  }
  // copy detector mapping
  API::ISpectrum *spectrum = working_ws->getSpectrum(0);
  spectrum->setSpectrumNo(specNum1);
  spectrum->clearDetectorIDs();
  spectrum->addDetectorIDs(pSpectr1->getDetectorIDs());
  spectrum = working_ws->getSpectrum(1);
  spectrum->setSpectrumNo(specNum2);
  spectrum->clearDetectorIDs();
  spectrum->addDetectorIDs(pSpectr2->getDetectorIDs());

  if (inputWS->getAxis(0)->unit()->caption() != "Energy") {
    API::IAlgorithm_sptr conv = createChildAlgorithm("ConvertUnits");
    conv->initialize();
    conv->setProperty("InputWorkspace", working_ws);
    conv->setProperty("OutputWorkspace", working_ws);
    conv->setPropertyValue("Target", "Energy");
    conv->setPropertyValue("EMode", "Elastic");
    // conv->setProperty("AlignBins",true); --> throws due to bug in
    // ConvertUnits
    conv->execute();
  }

  return working_ws;
}
/**function calculates list of provisional chopper opening times.
*@param TOF_range -- std::pair containing min and max time, of signal
*                    measured on monitors
*@param  ChopDelay -- the time of flight neutrons travel from source
*                     to the chopper opening.
*@param  Period  -- period of chopper openings

*@return guess_opening_times -- vector of times at which neutrons may
*                               pass through the chopper.
*/
void GetAllEi::findGuessOpeningTimes(const std::pair<double, double> &TOF_range,
                                     double ChopDelay, double Period,
                                     std::vector<double> &guess_opening_times) {

  if (ChopDelay >= TOF_range.second) {
    std::string chop = boost::str(boost::format("%.2g") % ChopDelay);
    std::string t_min = boost::str(boost::format("%.2g") % TOF_range.first);
    std::string t_max = boost::str(boost::format("%.2g") % TOF_range.second);
    throw std::runtime_error("Logical error: Chopper opening time: " + chop +
                             " is outside of time interval: " + t_min + ":" +
                             t_max + " of the signal, measured on monitors.");
  }

  // number of times chopper with specified rotation period opens.
  size_t n_openings =
      static_cast<size_t>((TOF_range.second - ChopDelay) / Period) + 1;
  // number of periods falling outside of the time period, measuring on monitor.
  size_t n_start(0);
  if (ChopDelay < TOF_range.first) {
    n_start = static_cast<size_t>((TOF_range.first - ChopDelay) / Period) + 1;
    n_openings -= n_start;
  }

  guess_opening_times.resize(n_openings);
  for (size_t i = n_start; i < n_openings + n_start; i++) {
    guess_opening_times[i - n_start] =
        ChopDelay + static_cast<double>(i) * Period;
  }
}
/**Return pointer to log value for property with specified name
*@param -- inputWS workspace with logs attached
*@param -- propertyName name of the property to find log for
*
*@return -- pointer to property which contain the log requested or nullptr if
*           no log found or other errors identified.
*/
Kernel::Property *
GetAllEi::getPLogForProperty(const API::MatrixWorkspace_sptr &inputWS,
                             const std::string &propertyName) {

  std::string LogName = this->getProperty(propertyName);
  if (boost::iequals(LogName, "Defined in IDF")) {
    auto AllNames = m_chopper->getStringParameter(propertyName);
    if (AllNames.size() != 1)
      return nullptr;
    LogName = AllNames[0];
  }
  auto pIProperty = (inputWS->run().getProperty(LogName));

  return pIProperty;
}

/**Return average time series log value for the appropriately filtered log
* @param inputWS      -- shared pointer to the input workspace containing
*                        the log to process
* @param propertyName -- log name
* @param splitter     -- array of Kernel::splittingInterval data, used to
*                        filter input events or empty array to use
*                        experiment start/end times.
*/
double
GetAllEi::getAvrgLogValue(const API::MatrixWorkspace_sptr &inputWS,
                          const std::string &propertyName,
                          std::vector<Kernel::SplittingInterval> &splitter) {

  auto pIProperty = getPLogForProperty(inputWS, propertyName);

  // this will always provide a defined pointer as this has been verified in
  // validator.
  auto pTimeSeries =
      dynamic_cast<Kernel::TimeSeriesProperty<double> *>(pIProperty);

  if (splitter.size() == 0) {
    auto TimeStart = inputWS->run().startTime();
    auto TimeEnd = inputWS->run().endTime();
    pTimeSeries->filterByTime(TimeStart, TimeEnd);
  } else {
    pTimeSeries->filterByTimes(splitter);
  }
  if (pTimeSeries->size() == 0) {
    throw std::runtime_error(
        "Can not find average value for log defined by property" +
        propertyName + " As no valid log values are found.");
  }

  return pTimeSeries->getStatistics().mean;
}
/**Analyze chopper logs and identify chopper speed and delay
@param  inputWS    -- sp to workspace with attached logs.
@return chop_speed -- chopper speed in uSec
@return chop_delay -- chopper delay in uSec
*/
void GetAllEi::findChopSpeedAndDelay(const API::MatrixWorkspace_sptr &inputWS,
                                     double &chop_speed, double &chop_delay) {

  // TODO: Make it dependent on inputWS time range

  std::vector<Kernel::SplittingInterval> splitter;
  if (m_FilterLogName.size() > 0) {
    std::unique_ptr<Kernel::TimeSeriesProperty<double>> pDerivative;
    // pointer will not be null as this has been verified in validators
    auto pTimeSeries = dynamic_cast<Kernel::TimeSeriesProperty<double> *>(
        inputWS->run().getProperty(m_FilterLogName));
    if (!pTimeSeries)
      throw std::runtime_error(
          "findChopSpeedAndDelay: filtering log: " + m_FilterLogName +
          " can not be interpreted as time series property of type 'double'");

    // Define selecting function
    bool inSelection(false);
    // time interval to select (start-end)
    Kernel::DateAndTime startTime, endTime;
    /**Select time interval on the basis of previous time interval state */
    auto SelectInterval = [&startTime, &endTime, &inSelection](
        const Kernel::DateAndTime &t_beg, const Kernel::DateAndTime &t_end,
        double value) {

      if (value > 0) {
        if (!inSelection) {
          startTime = t_beg;
        }
        inSelection = true;
      } else {
        if (inSelection) {
          inSelection = false;
          if (endTime > startTime)
            return true;
        }
      }
      endTime = t_end;
      return false;
    };
    //
    // Analyze filtering log
    auto dateAndTimes = pTimeSeries->valueAsCorrectMap();
    auto it = dateAndTimes.begin();
    auto next = it;
    next++;
    std::map<Kernel::DateAndTime, double> derivMap;
    auto itder = it;
    if (m_FilterWithDerivative) {
      pDerivative = pTimeSeries->getDerivative();
      derivMap = pDerivative->valueAsCorrectMap();
      itder = derivMap.begin();
    }

    // initialize selection log
    if (dateAndTimes.size() <= 1) {
      SelectInterval(it->first, it->first, itder->second);
      if (inSelection) {
        startTime = inputWS->run().startTime();
        endTime = inputWS->run().endTime();
        Kernel::SplittingInterval interval(startTime, endTime, 0);
        splitter.push_back(interval);
      } else {
        throw std::runtime_error("filter log :" + m_FilterLogName +
                                 " filters all data points. Nothing to do");
      }
    } else {
      SelectInterval(it->first, next->first, itder->second);
    }

    // if its filtered using log, both iterator walk through the same values
    // if use derivative, derivative's values are used for filtering