/** Create the final output workspace after converting the X axis
* @returns the final output workspace
*
* @param progress :: Progress indicator
* @param targetUnit :: Target conversion unit
* @param inputWS :: Input workspace
* @param nHist :: Stores the number of histograms
*/
MatrixWorkspace_sptr ConvertSpectrumAxis2::createOutputWorkspace(
API::Progress &progress, const std::string &targetUnit,
API::MatrixWorkspace_sptr &inputWS, size_t nHist) {
// Create the output workspace. Can not re-use the input one because the
// spectra are re-ordered.
MatrixWorkspace_sptr outputWorkspace = WorkspaceFactory::Instance().create(
inputWS, m_indexMap.size(), inputWS->x(0).size(), inputWS->y(0).size());
// Now set up a new numeric axis holding the theta values corresponding to
// each spectrum.
auto const newAxis = new NumericAxis(m_indexMap.size());
outputWorkspace->replaceAxis(1, newAxis);
progress.setNumSteps(nHist + m_indexMap.size());
// Set the units of the axis.
if (targetUnit == "theta" || targetUnit == "Theta" ||
targetUnit == "signed_theta" || targetUnit == "SignedTheta") {
newAxis->unit() = boost::make_shared<Units::Degrees>();
} else if (targetUnit == "ElasticQ") {
newAxis->unit() = UnitFactory::Instance().create("MomentumTransfer");
} else if (targetUnit == "ElasticQSquared") {
newAxis->unit() = UnitFactory::Instance().create("QSquared");
}
std::multimap<double, size_t>::const_iterator it;
size_t currentIndex = 0;
for (it = m_indexMap.begin(); it != m_indexMap.end(); ++it) {
// Set the axis value.
newAxis->setValue(currentIndex, it->first);
// Copy over the data.
outputWorkspace->setHistogram(currentIndex, inputWS->histogram(it->second));
// We can keep the spectrum numbers etc.
outputWorkspace->getSpectrum(currentIndex)
.copyInfoFrom(inputWS->getSpectrum(it->second));
++currentIndex;
progress.report("Creating output workspace...");
}
return outputWorkspace;
}
/** Forms the quadrature phase signal (squashogram)
* @param ws :: [input] workspace containing the measured spectra
* @param phase :: [input] table workspace containing the detector phases
* @param n0 :: [input] vector containing the normalization constants
* @return :: workspace containing the quadrature phase signal
*/
API::MatrixWorkspace_sptr
PhaseQuadMuon::squash(const API::MatrixWorkspace_sptr &ws,
const API::ITableWorkspace_sptr &phase,
const std::vector<double> &n0) {
// Poisson limit: below this number we consider we don't have enough
// statistics
// to apply sqrt(N). This is an arbitrary number used in the original code
// provided by scientists
const double poissonLimit = 30.;
// Muon life time in microseconds
const double muLife = PhysicalConstants::MuonLifetime * 1e6;
const size_t nspec = ws->getNumberHistograms();
if (n0.size() != nspec) {
throw std::invalid_argument("Invalid normalization constants");
}
auto names = phase->getColumnNames();
for (auto &name : names) {
std::transform(name.begin(), name.end(), name.begin(), ::tolower);
}
auto phaseIndex = findName(phaseNames, names);
auto asymmetryIndex = findName(asymmNames, names);
// Get the maximum asymmetry
double maxAsym = 0.;
for (size_t h = 0; h < nspec; h++) {
if (phase->Double(h, asymmetryIndex) > maxAsym &&
phase->Double(h, asymmetryIndex) != ASYMM_ERROR) {
maxAsym = phase->Double(h, asymmetryIndex);
}
}
if (maxAsym == 0.0) {
throw std::invalid_argument("Invalid detector asymmetries");
}
std::vector<bool> emptySpectrum;
emptySpectrum.reserve(nspec);
std::vector<double> aj, bj;
{
// Calculate coefficients aj, bj
double sxx = 0.;
double syy = 0.;
double sxy = 0.;
for (size_t h = 0; h < nspec; h++) {
emptySpectrum.push_back(
std::all_of(ws->y(h).begin(), ws->y(h).end(),
[](double value) { return value == 0.; }));
if (!emptySpectrum[h]) {
const double asym = phase->Double(h, asymmetryIndex) / maxAsym;
const double phi = phase->Double(h, phaseIndex);
const double X = n0[h] * asym * cos(phi);
const double Y = n0[h] * asym * sin(phi);
sxx += X * X;
syy += Y * Y;
sxy += X * Y;
}
}
const double lam1 = 2 * syy / (sxx * syy - sxy * sxy);
const double mu1 = 2 * sxy / (sxy * sxy - sxx * syy);
const double lam2 = 2 * sxy / (sxy * sxy - sxx * syy);
const double mu2 = 2 * sxx / (sxx * syy - sxy * sxy);
for (size_t h = 0; h < nspec; h++) {
if (emptySpectrum[h]) {
aj.push_back(0.0);
bj.push_back(0.0);
} else {
const double asym = phase->Double(h, asymmetryIndex) / maxAsym;
const double phi = phase->Double(h, phaseIndex);
const double X = n0[h] * asym * cos(phi);
const double Y = n0[h] * asym * sin(phi);
aj.push_back((lam1 * X + mu1 * Y) * 0.5);
bj.push_back((lam2 * X + mu2 * Y) * 0.5);
}
}
}
const size_t npoints = ws->blocksize();
// Create and populate output workspace
API::MatrixWorkspace_sptr ows =
API::WorkspaceFactory::Instance().create(ws, 2, npoints + 1, npoints);
// X
ows->setSharedX(0, ws->sharedX(0));
ows->setSharedX(1, ws->sharedX(0));
// Phase quadrature
auto &realY = ows->mutableY(0);
auto &imagY = ows->mutableY(1);
auto &realE = ows->mutableE(0);
auto &imagE = ows->mutableE(1);
const auto xPointData = ws->histogram(0).points();
// First X value
const double X0 = xPointData.front();
// calculate exponential decay outside of the loop
std::vector<double> expDecay = xPointData.rawData();
std::transform(expDecay.begin(), expDecay.end(), expDecay.begin(),
[X0, muLife](double x) { return exp(-(x - X0) / muLife); });
for (size_t i = 0; i < npoints; i++) {
for (size_t h = 0; h < nspec; h++) {
if (!emptySpectrum[h]) {
// (X,Y,E) with exponential decay removed
const double X = ws->x(h)[i];
const double exponential = n0[h] * exp(-(X - X0) / muLife);
const double Y = ws->y(h)[i] - exponential;
const double E =
(ws->y(h)[i] > poissonLimit) ? ws->e(h)[i] : sqrt(exponential);
realY[i] += aj[h] * Y;
imagY[i] += bj[h] * Y;
realE[i] += aj[h] * aj[h] * E * E;
imagE[i] += bj[h] * bj[h] * E * E;
}
}
realE[i] = sqrt(realE[i]);
imagE[i] = sqrt(imagE[i]);
// Regain exponential decay
realY[i] /= expDecay[i];
imagY[i] /= expDecay[i];
realE[i] /= expDecay[i];
imagE[i] /= expDecay[i];
}
// New Y axis label
ows->setYUnit("Asymmetry");
return ows;
}