/*
 * 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.math.analysis.integration;

import org.apache.commons.math.ConvergenceException;
import org.apache.commons.math.ConvergingAlgorithm;
import org.apache.commons.math.FunctionEvaluationException;
import org.apache.commons.math.analysis.UnivariateRealFunction;

/**
 * Interface for univariate real integration algorithms.
 * 
 * @version $Revision$ $Date$
 * @since 1.2
 */
public interface UnivariateRealIntegrator extends ConvergingAlgorithm {

	/**
	 * Set the lower limit for the number of iterations.
	 * <p>
	 * Minimal iteration is needed to avoid false early convergence, e.g. the
	 * sample points happen to be zeroes of the function. Users can use the
	 * default value or choose one that they see as appropriate.
	 * </p>
	 * <p>
	 * A <code>ConvergenceException</code> will be thrown if this number is not
	 * met.
	 * </p>
	 *
	 * @param count
	 *            minimum number of iterations
	 */
	void setMinimalIterationCount(int count);

	/**
	 * Get the lower limit for the number of iterations.
	 * 
	 * @return the actual lower limit
	 */
	int getMinimalIterationCount();

	/**
	 * Reset the lower limit for the number of iterations to the default.
	 * <p>
	 * The default value is supplied by the implementation.
	 * </p>
	 * 
	 * @see #setMinimalIterationCount(int)
	 */
	void resetMinimalIterationCount();

	/**
	 * Integrate the function in the given interval.
	 * 
	 * @param min
	 *            the lower bound for the interval
	 * @param max
	 *            the upper bound for the interval
	 * @return the value of integral
	 * @throws ConvergenceException
	 *             if the maximum iteration count is exceeded or the integrator
	 *             detects convergence problems otherwise
	 * @throws FunctionEvaluationException
	 *             if an error occurs evaluating the function
	 * @throws IllegalArgumentException
	 *             if min > max or the endpoints do not satisfy the requirements
	 *             specified by the integrator
	 * @deprecated replaced by
	 *             {@link #integrate(UnivariateRealFunction, double, double)}
	 *             since 2.0
	 */
	@Deprecated
	double integrate(double min, double max)
			throws ConvergenceException, FunctionEvaluationException, IllegalArgumentException;

	/**
	 * Integrate the function in the given interval.
	 * 
	 * @param f
	 *            the integrand function
	 * @param min
	 *            the lower bound for the interval
	 * @param max
	 *            the upper bound for the interval
	 * @return the value of integral
	 * @throws ConvergenceException
	 *             if the maximum iteration count is exceeded or the integrator
	 *             detects convergence problems otherwise
	 * @throws FunctionEvaluationException
	 *             if an error occurs evaluating the function
	 * @throws IllegalArgumentException
	 *             if min > max or the endpoints do not satisfy the requirements
	 *             specified by the integrator
	 */
	double integrate(UnivariateRealFunction f, double min, double max)
			throws ConvergenceException, FunctionEvaluationException, IllegalArgumentException;

	/**
	 * Get the result of the last run of the integrator.
	 * 
	 * @return the last result
	 * @throws IllegalStateException
	 *             if there is no result available, either because no result was
	 *             yet computed or the last attempt failed
	 */
	double getResult() throws IllegalStateException;

}
