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Diffstat (limited to 'src/main/java/com/softsynth/math/ChebyshevPolynomial.java')
-rw-r--r-- | src/main/java/com/softsynth/math/ChebyshevPolynomial.java | 45 |
1 files changed, 45 insertions, 0 deletions
diff --git a/src/main/java/com/softsynth/math/ChebyshevPolynomial.java b/src/main/java/com/softsynth/math/ChebyshevPolynomial.java new file mode 100644 index 0000000..bc0e854 --- /dev/null +++ b/src/main/java/com/softsynth/math/ChebyshevPolynomial.java @@ -0,0 +1,45 @@ +/* + * Copyright 1997 Phil Burk, Mobileer Inc + * + * 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 com.softsynth.math; + +/** + * ChebyshevPolynomial<br> + * Used to generate data for waveshaping table oscillators. + * + * @author Nick Didkovsky (C) 1997 Phil Burk and Nick Didkovsky + */ + +public class ChebyshevPolynomial { + static final Polynomial twoX = new Polynomial(2, 0); + static final Polynomial one = new Polynomial(1); + static final Polynomial oneX = new Polynomial(1, 0); + + /** + * Calculates Chebyshev polynomial of specified integer order. Recursively generated using + * relation Tk+1(x) = 2xTk(x) - Tk-1(x) + * + * @return Chebyshev polynomial of specified order + */ + public static Polynomial T(int order) { + if (order == 0) + return one; + else if (order == 1) + return oneX; + else + return Polynomial.minus(Polynomial.mult(T(order - 1), (twoX)), T(order - 2)); + } +} |