SigmoidalKernel.java
- /*
- * MIT License
- *
- * Copyright (c) 2009-2016 Ignacio Calderon <https://github.com/kronenthaler>
- *
- * Permission is hereby granted, free of charge, to any person obtaining a copy
- * of this software and associated documentation files (the "Software"), to deal
- * in the Software without restriction, including without limitation the rights
- * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
- * copies of the Software, and to permit persons to whom the Software is
- * furnished to do so, subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be included in all
- * copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
- * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
- * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
- * SOFTWARE.
- */
- package libai.common.kernels;
- import libai.common.matrix.Matrix;
- /**
- * Sigmoid Kernel. Follows the form: K(x,y) = tanh(a * xy + b), where a & b are
- * parameters of this kernel.
- *
- * @author kronenthaler
- */
- public class SigmoidalKernel implements Kernel {
- private static final long serialVersionUID = 5132845207274843125L;
- private final double a;
- private final double b;
- public SigmoidalKernel(double a, double b) {
- this.a = a;
- this.b = b;
- }
- @Override
- public double eval(Matrix A, Matrix B) {
- double dotProduct = A.dotProduct(B);
- return Math.tanh(a * dotProduct + b);
- }
- }