Exemple #1
0
/**
 * Tries to refine the initial cell using the supplied peaks
 *
 * This method tries to refine the initial unit cell using the indexed peaks
 * that are supplied in the PoldiPeakCollection. If there are unindexed peaks,
 * the cell will not be refined at all, instead the unmodified initial cell
 * is returned.
 *
 * @param initialCell :: String with the initial unit cell
 * @param crystalSystem :: Crystal system name
 * @param peakCollection :: Collection of bragg peaks, must be indexed
 *
 * @return String for refined unit cell
 */
std::string PoldiFitPeaks2D::getRefinedStartingCell(
    const std::string &initialCell, const std::string &latticeSystem,
    const PoldiPeakCollection_sptr &peakCollection) {

  Geometry::UnitCell cell = Geometry::strToUnitCell(initialCell);

  ILatticeFunction_sptr latticeFunction =
      boost::dynamic_pointer_cast<ILatticeFunction>(
          FunctionFactory::Instance().createFunction("LatticeFunction"));

  latticeFunction->setLatticeSystem(latticeSystem);
  latticeFunction->fix(latticeFunction->parameterIndex("ZeroShift"));
  latticeFunction->setUnitCell(cell);

  // Remove errors from d-values
  PoldiPeakCollection_sptr clone = peakCollection->clone();
  for (size_t i = 0; i < clone->peakCount(); ++i) {
    PoldiPeak_sptr peak = clone->peak(i);

    // If there are unindexed peaks, don't refine, just return the initial cell
    if (peak->hkl() == MillerIndices()) {
      return initialCell;
    }

    peak->setD(UncertainValue(peak->d().value()));
  }

  TableWorkspace_sptr peakTable = clone->asTableWorkspace();

  IAlgorithm_sptr fit = createChildAlgorithm("Fit");
  fit->setProperty("Function",
                   boost::static_pointer_cast<IFunction>(latticeFunction));
  fit->setProperty("InputWorkspace", peakTable);
  fit->setProperty("CostFunction", "Unweighted least squares");
  fit->execute();

  Geometry::UnitCell refinedCell = latticeFunction->getUnitCell();

  return Geometry::unitCellToStr(refinedCell);
}
Exemple #2
0
/**
 * Return peak collection with integrated peaks
 *
 * This method takes a PoldiPeakCollection where the intensity is represented
 * by the maximum. Then it takes the profile function stored in the peak
 * collection, which must be the name of a registered
 * IPeakFunction-implementation. The parameters height and fwhm are assigned,
 * centre is set to 0 to avoid problems with the parameter transformation for
 * the integration from -inf to inf. The profiles are integrated using
 * a PeakFunctionIntegrator to the precision of 1e-10.
 *
 * The original peak collection is not modified, a new instance is created.
 *
 * @param rawPeakCollection :: PoldiPeakCollection
 * @return PoldiPeakCollection with integrated intensities
 */
PoldiPeakCollection_sptr PoldiFitPeaks2D::getIntegratedPeakCollection(
    const PoldiPeakCollection_sptr &rawPeakCollection) const {
  if (!rawPeakCollection) {
    throw std::invalid_argument(
        "Cannot proceed with invalid PoldiPeakCollection.");
  }

  if (!isValidDeltaT(m_deltaT)) {
    throw std::invalid_argument("Cannot proceed with invalid time bin size.");
  }

  if (!m_timeTransformer) {
    throw std::invalid_argument(
        "Cannot proceed with invalid PoldiTimeTransformer.");
  }

  if (rawPeakCollection->intensityType() == PoldiPeakCollection::Integral) {
    /* Intensities are integral already - don't need to do anything,
     * except cloning the collection, to make behavior consistent, since
     * integrating also results in a new peak collection.
     */
    return rawPeakCollection->clone();
  }

  /* If no profile function is specified, it's not possible to get integrated
   * intensities at all and we try to use the one specified by the user
   * instead.
   */
  std::string profileFunctionName = rawPeakCollection->getProfileFunctionName();

  if (!rawPeakCollection->hasProfileFunctionName()) {
    profileFunctionName = getPropertyValue("PeakProfileFunction");
  }

  std::vector<std::string> allowedProfiles =
      FunctionFactory::Instance().getFunctionNames<IPeakFunction>();

  if (std::find(allowedProfiles.begin(), allowedProfiles.end(),
                profileFunctionName) == allowedProfiles.end()) {
    throw std::runtime_error(
        "Cannot integrate peak profiles with invalid profile function.");
  }

  PoldiPeakCollection_sptr integratedPeakCollection =
      boost::make_shared<PoldiPeakCollection>(PoldiPeakCollection::Integral);
  integratedPeakCollection->setProfileFunctionName(profileFunctionName);

  // Preserve unit cell, point group
  assignCrystalData(integratedPeakCollection, rawPeakCollection);

  for (size_t i = 0; i < rawPeakCollection->peakCount(); ++i) {
    PoldiPeak_sptr peak = rawPeakCollection->peak(i);

    IPeakFunction_sptr profileFunction =
        boost::dynamic_pointer_cast<IPeakFunction>(
            FunctionFactory::Instance().createFunction(profileFunctionName));

    profileFunction->setHeight(peak->intensity());
    profileFunction->setFwhm(peak->fwhm(PoldiPeak::AbsoluteD));

    PoldiPeak_sptr integratedPeak = peak->clone();
    integratedPeak->setIntensity(UncertainValue(profileFunction->intensity()));
    integratedPeakCollection->addPeak(integratedPeak);
  }

  return integratedPeakCollection;
}