commons-math-legacy/src/main/java/org/apache/commons/math4/legacy/analysis/ParametricUnivariateFunction.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF 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
 *
 *      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 org.apache.commons.math4.legacy.analysis;

/**
 * An interface representing a real function that depends on one independent
 * variable plus some extra parameters.
 *
 * @since 3.0
 */
public interface ParametricUnivariateFunction {
    /**
     * Compute the value of the function.
     *
     * @param x Point for which the function value should be computed.
     * @param parameters Function parameters.
     * @return the value.
     */
    double value(double x, double ... parameters);

    /**
     * Compute the gradient of the function with respect to its parameters.
     *
     * @param x Point for which the function value should be computed.
     * @param parameters Function parameters.
     * @return the value.
     */
    double[] gradient(double x, double ... parameters);
}