/*
 * Zorbage: an algebraic data hierarchy for use in numeric processing.
 *
 * Copyright (C) 2016-2019 Barry DeZonia
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 * 
 * 1. Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDERS OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */
package nom.bdezonia.zorbage.algorithm;

import nom.bdezonia.zorbage.type.algebra.Addition;
import nom.bdezonia.zorbage.type.algebra.Algebra;
import nom.bdezonia.zorbage.type.algebra.Ordered;

/**
 * 
 * @author Barry DeZonia
 *
 */
public class NumberWithin {

	private NumberWithin() { }
	
	/**
	 * 
	 * @param algebra
	 * @param a
	 * @param b
	 * @param tol
	 * @return
	 */
	public static <T extends Algebra<T,U> & Ordered<U> & Addition<U>,U>
		boolean compute(T algebra, U a, U b, U tol)
	{
		U zero = algebra.construct();
		U diff = algebra.construct();
		if (algebra.isLess().call(tol, zero))
			throw new IllegalArgumentException("tolerance must be >= 0");
		int sigA = algebra.signum().call(a);
		int sigB = algebra.signum().call(b);
		if (sigA < 0) {
			if (sigB < 0) {
				if (algebra.isGreater().call(a, b))
					algebra.subtract().call(b, a, diff);
				else
					algebra.subtract().call(a, b, diff);
				if (algebra.isLess().call(diff, zero))
					algebra.negate().call(diff, diff);
				if (algebra.isGreater().call(diff, tol))
					return false;
				return true;
			}
			else if (sigB > 0) {

				if (algebra.isGreater().call(b, tol))
					return false;
				algebra.negate().call(tol, tol);
				if (algebra.isLess().call(a, tol))
					return false;
				// if here then they are within 2 tol of each other
				algebra.add().call(b, tol, diff);
				if (algebra.isGreater().call(diff, a))
					return false;
				return true;	
			}
			else { // sigB == 0
				algebra.negate().call(tol, tol);
				if (algebra.isLess().call(a, tol))
					return false;
				return true;
			}
		}
		else if (sigA > 0) {
			if (sigB < 0) {
				if (algebra.isGreater().call(a, tol))
					return false;
				algebra.negate().call(tol, tol);
				if (algebra.isLess().call(b, tol))
					return false;
				// if here then they are within 2 tol of each other
				algebra.add().call(a, tol, diff);
				if (algebra.isGreater().call(diff, b))
					return false;
				return true;	
			}
			else if (sigB > 0) {
				if (algebra.isLess().call(a, b))
					algebra.subtract().call(b, a, diff);
				else
					algebra.subtract().call(a, b, diff);
				if (algebra.isGreater().call(diff, tol))
					return false;
				return true;
			}
			else { // sigB == 0
				if (algebra.isGreater().call(a, tol))
					return false;
				return true;
			}
		}
		else { // sigA == 0
			if (sigB < 0) {
				algebra.negate().call(tol, tol);
				if (algebra.isLess().call(b, tol))
					return false;
				return true;
			}
			else if (sigB > 0) {
				if (algebra.isGreater().call(b, tol))
					return false;
				return true;
			}
			else { // sigB == 0
				// they both equal 0: they are within any nonnegative tolerance
				return true;
			}
		}
	}
}

@@ -1913,17 +1913,22 @@
  U b, U 
-t
+inputT
 ol)%0A%09%7B%0A%09
@@ -1990,16 +1990,55 @@
 ruct();%0A
+%09%09U tol = algebra.construct(inputTol);%0A
 %09%09if (al

Fix a bug due to unintended side effects