FluxUtilities.cc

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// -*- lsst-c++ -*-
/*
 * LSST Data Management System
 * Copyright 2008-2015 AURA/LSST.
 *
 * This product includes software developed by the
 * LSST Project (http://www.lsst.org/).
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the LSST License Statement and
 * the GNU General Public License along with this program.  If not,
 * see <http://www.lsstcorp.org/LegalNotices/>.
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#include "lsst/afw/table/BaseRecord.h"
#include "lsst/meas/base/FluxUtilities.h"
#include "lsst/meas/base/Transform.h"

namespace lsst {
namespace meas {
namespace base {

FluxResult::FluxResult()
        : instFlux(std::numeric_limits<meas::base::Flux>::quiet_NaN()),
          instFluxErr(std::numeric_limits<meas::base::FluxErrElement>::quiet_NaN()) {}

FluxResultKey FluxResultKey::addFields(afw::table::Schema& schema, std::string const& name,
                                       std::string const& doc) {
    FluxResultKey result;
    result._instFlux = schema.addField<meas::base::Flux>(schema.join(name, "instFlux"), doc, "count");
    result._instFluxErr = schema.addField<meas::base::FluxErrElement>(
            schema.join(name, "instFluxErr"), "1-sigma instFlux uncertainty", "count");
    return result;
}

FluxResult FluxResultKey::get(afw::table::BaseRecord const& record) const {
    FluxResult r;
    r.instFlux = record.get(_instFlux);
    r.instFluxErr = record.get(_instFluxErr);
    return r;
}

void FluxResultKey::set(afw::table::BaseRecord& record, FluxResult const& value) const {
    record.set(_instFlux, value.instFlux);
    record.set(_instFluxErr, value.instFluxErr);
}

MagResultKey MagResultKey::addFields(afw::table::Schema& schema, std::string const& name) {
    MagResultKey result;
    result._magKey = schema.addField<Mag>(schema.join(name, "mag"), "Magnitude");
    result._magErrKey = schema.addField<MagErrElement>(schema.join(name, "magErr"), "Error on magnitude");
    return result;
}

MagResult MagResultKey::get(afw::table::BaseRecord const& record) const {
    MagResult result = {record.get(_magKey), record.get(_magErrKey)};
    return result;
}

void MagResultKey::set(afw::table::BaseRecord& record, MagResult const& magResult) const {
    record.set(_magKey, magResult.mag);
    record.set(_magErrKey, magResult.magErr);
}

void MagResultKey::set(afw::table::BaseRecord& record, std::pair<double, double> const& magResult) const {
    record.set(_magKey, magResult.first);
    record.set(_magErrKey, magResult.second);
}

FluxTransform::FluxTransform(std::string const& name, afw::table::SchemaMapper& mapper)
        : BaseTransform{name} {
    // Map the flag through to the output
    mapper.addMapping(mapper.getInputSchema().find<afw::table::Flag>(name + "_flag").key);

    // Add keys for the magnitude and associated error
    _magKey = MagResultKey::addFields(mapper.editOutputSchema(), name);
}

void FluxTransform::operator()(afw::table::SourceCatalog const& inputCatalog,
                               afw::table::BaseCatalog& outputCatalog, afw::geom::SkyWcs const& wcs,
                               afw::image::Calib const& calib) const {
    checkCatalogSize(inputCatalog, outputCatalog);
    FluxResultKey instFluxKey(inputCatalog.getSchema()[_name]);
    afw::table::SourceCatalog::const_iterator inSrc = inputCatalog.begin();
    afw::table::BaseCatalog::iterator outSrc = outputCatalog.begin();
    {
        // While noThrow is in scope, converting a negative instFlux to a magnitude
        // returns NaN rather than throwing.
        NoThrowOnNegativeFluxContext noThrow;
        for (; inSrc != inputCatalog.end() && outSrc != outputCatalog.end(); ++inSrc, ++outSrc) {
            FluxResult instFluxResult = instFluxKey.get(*inSrc);
            _magKey.set(*outSrc, calib.getMagnitude(instFluxResult.instFlux, instFluxResult.instFluxErr));
        }
    }
}

NoThrowOnNegativeFluxContext::NoThrowOnNegativeFluxContext() {
    _throwOnNegative = afw::image::Calib::getThrowOnNegativeFlux();
    afw::image::Calib::setThrowOnNegativeFlux(false);
}

NoThrowOnNegativeFluxContext::~NoThrowOnNegativeFluxContext() {
    afw::image::Calib::setThrowOnNegativeFlux(_throwOnNegative);
}

}  // namespace base
}  // namespace meas
}  // namespace lsst