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/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package org.apache.ctakes.ytex.kernel.metric;

import java.util.Map;

/**
 * compute corpus-ic or intrinsic-ic based lin measure.
 * 
 * @author vijay
 * 
 */
public class LinMetric extends BaseSimilarityMetric {
	private boolean intrinsicIC = true;
	private boolean validCG = false;
	private String rootConcept = simSvc.getConceptGraph().getRoot();

	public boolean isIntrinsicIC() {
		return intrinsicIC;
	}

	public void setIntrinsicIC(boolean intrinsicIC) {
		this.intrinsicIC = intrinsicIC;
	}

	@Override
	public double similarity(String concept1, String concept2,
			Map conceptFilter, SimilarityInfo simInfo) {
		// don't bother if the concept graph is null
		if (!validCG)
			return 0d;
		// get lcs
		double lcsIC = initLcsIC(concept1, concept2, conceptFilter, simInfo,
				this.intrinsicIC);
		if (lcsIC == 0d) {
			return 0d;
		}
		// get ic of concepts
		double ic1 = simSvc.getIC(concept1, this.intrinsicIC);
		double ic2 = simSvc.getIC(concept2, this.intrinsicIC);
		// if the corpus IC is 0 and the concept is not the root, then we don't
		// have any IC on the concept and can't measure similarity - return 0
		if (!intrinsicIC && ic1 == 0 && !rootConcept.equals(concept1))
			return 0d;
		if (!intrinsicIC && ic2 == 0 && !rootConcept.equals(concept2))
			return 0d;
		double denom = ic1 + ic2;
		if (denom == 0)
			return 0d;
		return 2 * lcsIC / denom;
	}

	public LinMetric(ConceptSimilarityService simSvc, boolean intrinsicIC) {
		super(simSvc);
		this.intrinsicIC = intrinsicIC;
		this.validCG = simSvc.getConceptGraph() != null;
		if (!this.intrinsicIC && validCG) {
			rootConcept = simSvc.getConceptGraph().getRoot();
		}
	}

}