org.nd4j.evaluation.curves.BaseCurve Maven / Gradle / Ivy
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* Copyright (c) 2015-2018 Skymind, Inc.
*
* This program and the accompanying materials are made available under the
* terms of the Apache License, Version 2.0 which is available at
* https://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.
*
* SPDX-License-Identifier: Apache-2.0
******************************************************************************/
package org.nd4j.evaluation.curves;
import org.nd4j.evaluation.BaseEvaluation;
import org.nd4j.serde.json.JsonMappers;
import org.nd4j.shade.jackson.annotation.JsonTypeInfo;
import org.nd4j.shade.jackson.core.JsonProcessingException;
import java.io.IOException;
/**
* Abstract class for ROC and Precision recall curves
*
* @author Alex Black
*/
@JsonTypeInfo(use = JsonTypeInfo.Id.CLASS, include = JsonTypeInfo.As.PROPERTY)
public abstract class BaseCurve {
public static final int DEFAULT_FORMAT_PREC = 4;
/**
* @return The number of points in the curve
*/
public abstract int numPoints();
/**
* @return X axis values
*/
public abstract double[] getX();
/**
* @return Y-axis values
*/
public abstract double[] getY();
/**
* @return Title for the curve
*/
public abstract String getTitle();
/**
* @return Area under the curve
*/
protected double calculateArea() {
return calculateArea(getX(), getY());
}
protected double calculateArea(double[] x, double[] y) {
int nPoints = x.length;
double area = 0.0;
for (int i = 0; i < nPoints - 1; i++) {
double xLeft = x[i];
double yLeft = y[i];
double xRight = x[i + 1];
double yRight = y[i + 1];
//y axis: TPR
//x axis: FPR
double deltaX = Math.abs(xRight - xLeft); //Iterating in threshold order, so FPR decreases as threshold increases
double avg = (yRight + yLeft) / 2.0;
area += deltaX * avg;
}
return area;
}
protected String format(double d, int precision) {
return String.format("%." + precision + "f", d);
}
/**
* @return JSON representation of the curve
*/
public String toJson() {
try {
return JsonMappers.getMapper().writeValueAsString(this);
} catch (JsonProcessingException e) {
throw new RuntimeException(e);
}
}
/**
* @return YAML representation of the curve
*/
public String toYaml() {
try {
return JsonMappers.getYamlMapper().writeValueAsString(this);
} catch (JsonProcessingException e) {
throw new RuntimeException(e);
}
}
/**
*
* @param json JSON representation
* @param curveClass Class for the curve
* @param Type
* @return Instance of the curve
*/
public static T fromJson(String json, Class curveClass) {
try {
return JsonMappers.getMapper().readValue(json, curveClass);
} catch (IOException e) {
throw new RuntimeException(e);
}
}
/**
*
* @param yaml YAML representation
* @param curveClass Class for the curve
* @param Type
* @return Instance of the curve
*/
public static T fromYaml(String yaml, Class curveClass) {
try {
return JsonMappers.getYamlMapper().readValue(yaml, curveClass);
} catch (IOException e) {
throw new RuntimeException(e);
}
}
}