FieldDerivative.java
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* Licensed to the Hipparchus project under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The Hipparchus project 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
*
* 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.
*/
package org.hipparchus.analysis.differentiation;
import org.hipparchus.CalculusFieldElement;
import org.hipparchus.exception.MathIllegalArgumentException;
import org.hipparchus.util.FastMath;
/** Interface representing both the value and the differentials of a function.
* @param <S> the type of the field elements
* @param <T> the type of the function derivative
* @see Derivative
* @since 1.7
*/
public interface FieldDerivative<S extends CalculusFieldElement<S>, T extends FieldDerivative<S, T>>
extends CalculusFieldElement<T>, DifferentialAlgebra {
/** Get the value part of the function.
* @return value part of the value of the function
*/
S getValue();
/** Get a partial derivative.
* @param orders derivation orders with respect to each variable (if all orders are 0,
* the value is returned)
* @return partial derivative
* @see #getValue()
* @exception MathIllegalArgumentException if the numbers of variables does not
* match the instance
* @exception MathIllegalArgumentException if sum of derivation orders is larger
* than the instance limits
*/
S getPartialDerivative(int ... orders)
throws MathIllegalArgumentException;
/** {@inheritDoc} */
@Override
default double getReal() {
return getValue().getReal();
}
/** Create an instance corresponding to a constant Field value.
* <p>
* This default implementation is there so that no API gets broken
* by the next release, which is not a major one. Custom inheritors
* should probably overwrite it.
* </p>
* @param value constant value
* @return instance corresponding to a constant Field value
* @since 3.1
*/
default T newInstance(S value) {
return newInstance(value.getReal());
}
/** Create a new object with new value (zeroth-order derivative, as passed as input)
* and same derivatives of order one and above.
* <p>
* This default implementation is there so that no API gets broken
* by the next release, which is not a major one. Custom inheritors
* should probably overwrite it.
* </p>
* @param value zeroth-order derivative of new represented function
* @return new object with changed value
* @since 3.1
*/
default T withValue(S value) {
return add(newInstance(value.subtract(getValue())));
}
/** '+' operator.
* @param a right hand side parameter of the operator
* @return this+a
* @since 3.1
*/
default T add(S a) {
return withValue(getValue().add(a));
}
/** '-' operator.
* @param a right hand side parameter of the operator
* @return this-a
* @since 3.1
*/
default T subtract(S a) {
return withValue(getValue().subtract(a));
}
/** {@inheritDoc} */
@Override
default T log10() {
return log().divide(FastMath.log(10.));
}
/** {@inheritDoc} */
@Override
default T pow(T e) {
return log().multiply(e).exp();
}
/** {@inheritDoc} */
@Override
default T cosh() {
return (exp().add(negate().exp())).divide(2);
}
/** {@inheritDoc} */
@Override
default T sinh() {
return (exp().subtract(negate().exp())).divide(2);
}
/** {@inheritDoc} */
@Override
default T acos() {
return asin().negate().add(getPi().divide(2));
}
/** {@inheritDoc} */
@Override
default T ceil() {
return newInstance(getValue().ceil());
}
/** {@inheritDoc} */
@Override
default T floor() {
return newInstance(getValue().floor());
}
/** {@inheritDoc} */
@Override
default T rint() {
return newInstance(getValue().rint());
}
/** {@inheritDoc} */
@Override
default T ulp() {
return newInstance(getValue().ulp());
}
/** {@inheritDoc} */
@Override
default T sign() {
return newInstance(getValue().sign());
}
/** {@inheritDoc} */
@Override
default int getExponent() {
return getValue().getExponent();
}
}