/**
* Return a pair of (minimum Q, maximum Q) for given
* indirect geometry workspace. Estimates the Q range from all detectors.
* If workspace contains grouped detectors/not all detectors are linked
* to a spectrum, the returned interval may be larger than actually needed.
* @param ws a workspace
* @param minE minimum energy transfer in ws
* @param maxE maximum energy transfer in ws
* @return a pair containing global minimun and maximum Q
*/
std::pair<double, double>
SofQCommon::qBinHintsIndirect(const API::MatrixWorkspace &ws, const double minE,
const double maxE) const {
using namespace Mantid::PhysicalConstants;
auto minQ = std::numeric_limits<double>::max();
auto maxQ = std::numeric_limits<double>::lowest();
const auto &detectorInfo = ws.detectorInfo();
for (size_t i = 0; i < detectorInfo.size(); ++i) {
if (detectorInfo.isMasked(i) || detectorInfo.isMonitor(i)) {
continue;
}
const auto twoTheta = detectorInfo.twoTheta(i);
const auto &det = detectorInfo.detector(i);
const auto Q1 = indirectQ(minE, twoTheta, &det);
const auto Q2 = indirectQ(maxE, twoTheta, &det);
const auto minmaxQ = std::minmax(Q1, Q2);
if (minmaxQ.first < minQ) {
minQ = minmaxQ.first;
}
if (minmaxQ.second > maxQ) {
maxQ = minmaxQ.second;
}
}
if (minQ == std::numeric_limits<double>::max()) {
throw std::runtime_error("Could not determine Q binning: workspace does "
"not contain usable spectra.");
}
return std::make_pair(minQ, maxQ);
}
