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// Copyright Yahoo. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
#include "jarowinklerdistancefeature.h"
#include "utils.h"
#include <vespa/searchlib/fef/featurenamebuilder.h>
#include <vespa/searchlib/fef/properties.h>
#include <vespa/vespalib/util/stringfmt.h>
#include <vespa/vespalib/locale/c.h>
#include <vespa/vespalib/util/stash.h>
namespace search::features {
//-----------------------------------------------------------------------------
// JaroWinklerDistanceConfig
//-----------------------------------------------------------------------------
JaroWinklerDistanceConfig::JaroWinklerDistanceConfig() :
fieldId(search::fef::IllegalHandle),
fieldBegin(0),
fieldEnd(std::numeric_limits<uint32_t>::max()),
boostThreshold(0.7f),
prefixSize(4u)
{
// empty
}
//-----------------------------------------------------------------------------
// JaroWinklerDistanceExecutor
//-----------------------------------------------------------------------------
JaroWinklerDistanceExecutor::JaroWinklerDistanceExecutor(const search::fef::IQueryEnvironment &env,
const JaroWinklerDistanceConfig &config) :
search::fef::FeatureExecutor(),
_config(config),
_termFieldHandles(),
_md(nullptr)
{
for (uint32_t i = 0; i < env.getNumTerms(); ++i) {
_termFieldHandles.push_back(util::getTermFieldHandle(env, i, config.fieldId));
}
}
void
JaroWinklerDistanceExecutor::execute(uint32_t docId)
{
// Build a list of field position iterators, one per query term.
std::vector<search::fef::FieldPositionsIterator> pos;
for (uint32_t term = 0; term < _termFieldHandles.size(); ++term) {
search::fef::FieldPositionsIterator it; // this is not vaild
const search::fef::TermFieldHandle &handle = _termFieldHandles[term];
if (handle != search::fef::IllegalHandle) {
const search::fef::TermFieldMatchData &tfmd = *_md->resolveTermField(handle);
if (tfmd.getDocId() == docId) {
it = tfmd.getIterator();
}
}
pos.push_back(it);
}
// Assign the jaroWinkler distance to this executor's output.
outputs().set_number(0, 1 - jaroWinklerProximity(pos, (uint32_t)inputs().get_number(0)));
}
void
JaroWinklerDistanceExecutor::handle_bind_match_data(const fef::MatchData &md)
{
_md = &md;
}
namespace {
uint32_t
matches(const std::vector<search::fef::FieldPositionsIterator> &termPos,
uint32_t fieldLen, uint32_t *numTransposes)
{
(*numTransposes) = 0u;
uint32_t ret = 0;
uint32_t halfLen = termPos.size() > fieldLen ? (fieldLen / 2 + 1) : (termPos.size() / 2 + 1);
for (uint32_t i = 0; i < termPos.size(); ++i) {
uint32_t min = i > halfLen ? i - halfLen : 0u;
uint32_t max = std::min(fieldLen, i + halfLen);
for (search::fef::FieldPositionsIterator it = termPos[i]; it.valid() && it.getPosition() <= max; it.next()) {
uint32_t pos = it.getPosition();
if (pos >= min && pos <= max) {
if (pos != i) {
(*numTransposes)++;
}
ret++;
break;
}
}
}
(*numTransposes) /= 2;
return ret;
}
uint32_t
prefixMatch(const std::vector<search::fef::FieldPositionsIterator> &termPos, uint32_t fieldLen, uint32_t maxLen)
{
uint32_t len = std::min((uint32_t)termPos.size(), std::min(fieldLen, maxLen));
for (uint32_t i = 0; i < len; ++i) {
if (!termPos[i].valid() || termPos[i].getPosition() != i) {
return i;
}
}
return len;
}
feature_t
jaroMeasure(const std::vector<search::fef::FieldPositionsIterator> &termPos, uint32_t fieldLen)
{
// _P_A_R_A_N_O_I_A_
if (termPos.empty() || fieldLen == 0) {
return 0.0f;
}
uint32_t numTransposes = 0;
uint32_t numMatches = matches(termPos, fieldLen, &numTransposes);
if (numMatches == 0u) {
return 0.0f;
}
return (((feature_t)numMatches / termPos.size()) +
((feature_t)numMatches / fieldLen) +
((feature_t)numMatches - numTransposes) / numMatches) / 3.0f;
}
} // namespace
feature_t
JaroWinklerDistanceExecutor::jaroWinklerProximity(const std::vector<search::fef::FieldPositionsIterator> &termPos, uint32_t fieldLen)
{
feature_t ret = std::min(1.0, std::max(0.0, jaroMeasure(termPos, fieldLen)));
if (ret > _config.boostThreshold) {
ret += 0.1f * prefixMatch(termPos, fieldLen, _config.prefixSize) * (1 - ret); // less boost close to 1
}
return ret;
}
//-----------------------------------------------------------------------------
// JaroWinklerDistanceBlueprint
//-----------------------------------------------------------------------------
JaroWinklerDistanceBlueprint::JaroWinklerDistanceBlueprint() :
search::fef::Blueprint("jaroWinklerDistance"),
_config()
{
// empty
}
void
JaroWinklerDistanceBlueprint::visitDumpFeatures(const search::fef::IIndexEnvironment &,
search::fef::IDumpFeatureVisitor &) const
{
// empty
}
bool
JaroWinklerDistanceBlueprint::setup(const search::fef::IIndexEnvironment &env,
const search::fef::ParameterList ¶ms)
{
_config.fieldId = params[0].asField()->id();
vespalib::string boostThreshold = env.getProperties().lookup(getName(), "boostThreshold").getAt(0);
_config.boostThreshold = boostThreshold.empty() ? 0.7f : vespalib::locale::c::atof(boostThreshold.c_str());
vespalib::string prefixSize = env.getProperties().lookup(getName(), "prefixSize").getAt(0);
_config.prefixSize = prefixSize.empty() ? 4 : atoi(prefixSize.c_str());
defineInput(vespalib::make_string("fieldLength(%s)", params[0].getValue().c_str()));
describeOutput("out", "JaroWinklerDistance distance measure.");
return true;
}
search::fef::Blueprint::UP
JaroWinklerDistanceBlueprint::createInstance() const
{
return std::make_unique<JaroWinklerDistanceBlueprint>();
}
search::fef::FeatureExecutor &
JaroWinklerDistanceBlueprint::createExecutor(const search::fef::IQueryEnvironment &env, vespalib::Stash &stash) const
{
return stash.create<JaroWinklerDistanceExecutor>(env, _config);
}
}
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