/*******************************************************************************
* Copyright (c) 2010 Haifeng Li
*
* Licensed 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 smile.interpolation;
/**
* Piecewise linear interpolation. Linear interpolation, sometimes known as
* lerp, is quick and easy, but it is not very precise. Another disadvantage
* is that the interpolant is not differentiable at the control points x.
*
* @author Haifeng Li
*/
public class LinearInterpolation extends AbstractInterpolation {
/**
* Constructor.
*/
public LinearInterpolation(double[] x, double[] y) {
super(x, y);
}
@Override
double rawinterp(int j, double x) {
if (xx[j] == xx[j + 1]) {
return yy[j];
} else {
return yy[j] + ((x - xx[j]) / (xx[j + 1] - xx[j])) * (yy[j + 1] - yy[j]);
}
}
}