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A Java library with generally useful classes and methods.
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/*
* Copyright 2019 Andy Turner, University of Leeds.
*
* 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 uk.ac.leeds.ccg.generic.math;
//import ch.obermuhlner.math.big.BigRational;
import java.math.BigDecimal;
import java.math.BigInteger;
import java.math.MathContext;
import java.math.RoundingMode;
/**
* Generic Math
*
* Methods for adding two Numbers and testing if Numbers are in the range of
* other Numbers.
*
* @author Andy Turner
* @version 1.0
*/
public class Generic_Math {
/**
* Stores the second largest finite double. The largest is:
*
* new BigDecimal(Double.MAX_VALUE)
*
* Values greater than this are best not stored as doubles and nearby values
* may not necessarily be stored any differently to this - if stored as a
* double - due to the way floating point numbers operate with narrowing
* conversions.
*/
public static final BigDecimal DOUBLE_MAXVALUE = new BigDecimal(
String.valueOf(Double.MAX_VALUE));
//public static final BigDecimal DOUBLE_MAXVALUE = new BigDecimal(
// Double.toString(Double.MAX_VALUE));
/**
* Stores the third largest finite double.
*/
public static final BigDecimal DOUBLE_MAXVALUE_PEN = new BigDecimal(
String.valueOf(Math.nextDown(Double.MAX_VALUE)));
/**
* Stores a negative finite double with the second largest magnitude. The
* largest is:
*
* new BigDecimal(-Double.MAX_VALUE)
*
* Values less than this are best not stored as doubles and nearby values
* may not necessarily be stored any differently to this - if stored as a
* double - due to the way floating point numbers operate with narrowing
* conversions.
*/
public static final BigDecimal DOUBLE_MAXVALUE_NEG = DOUBLE_MAXVALUE.negate();
/**
* Stores a negative finite double with the third largest magnitude.
*/
public static final BigDecimal DOUBLE_MINVALUE_PEN = new BigDecimal(
String.valueOf(Math.nextUp(-Double.MAX_VALUE)));
/**
* Used for testing. If values are greater than this then storing them as
* Float values is dubious. The toString() conversion is necessary otherwise
* the number is too large.
*/
public static final BigDecimal FLOAT_MAXVALUE = new BigDecimal(
String.valueOf(Float.MAX_VALUE));
//public static final BigDecimal FLOAT_MAXVALUE = new BigDecimal(
// Float.toString(Float.MAX_VALUE));
/**
* Used for testing. If values are greater than this then they cannot be stored as
* Shorts.
*/
public static final BigInteger SHORT_MAXVALUE = new BigInteger(
Short.toString(Short.MAX_VALUE));
/**
* Used for testing. If values are less than this then storing them as Float
* values is dubious.
*/
public static final BigDecimal FLOAT_MAXVALUE_NEG = FLOAT_MAXVALUE.negate();
/**
* For adding two generic Numbers x and y of the same type. The numbers x
* and y are converted as appropriate into BigInteger or BigDecimal (for
* integer type or floating point numbers respectively - if they are not
* already of these types). In the general case, the converted numbers are
* then added and the result cast into the type T and returned. If the
* result of adding the two numbers cannot be stored exactly in the case of
* integer type numerical addition then an ArithmeticException is thrown. If
* the result of adding the two numbers is beyond the range in the type of
* numbers being added then an ArithmeticExcpetion is thrown unless
* infinities are involved (except when the two numbers being added are
* opposite infinities - in which case an ArithmeticException is thrown). If
* one number is positive or negative infinity then that infinity is
* returned. In cases where the values being added are represented in
* floating point precision the results are a consequence of a narrowing
* digital conversion. (N.B. If desirable then if numbers do not increase or
* decrease as expected then there could be an implementation that throws an
* ArithmeticException in cases where a narrowing digital conversion does
* not result in a larger or smaller number as is typically mathematically
* expected in a sum.
*
* @param The type T of the Numbers x and y.
* @param x A Number to add.
* @param y A Number to add.
* @return The result of adding x and y expressed in the same type as x and
* y.
*/
public static T add(T x, T y) {
if (x == null || y == null) {
return null;
}
// if (x instanceof BigRational) {
// return (T) ((BigRational) x).add((BigRational) y);
// } else
if (x instanceof BigDecimal) {
return (T) ((BigDecimal) x).add((BigDecimal) y);
} else if (x instanceof BigInteger) {
return (T) ((BigInteger) x).add((BigInteger) y);
} else {
if (x instanceof Double) {
Double x0 = (Double) x;
// Deal with special cases.
if (x0.isNaN()) {
return (T) x0;
}
Double y0 = (Double) y;
if (y0.isNaN()) {
return (T) y0;
}
if (x0 == Double.POSITIVE_INFINITY) {
if (y0 == Double.NEGATIVE_INFINITY) {
throw new ArithmeticException("Attempting to add "
+ "positive and negative infinity.");
//return (T) (Double) Double.NaN;
} else {
return (T) x0;
}
} else if (x0 == Double.NEGATIVE_INFINITY) {
if (y0 == Double.POSITIVE_INFINITY) {
throw new ArithmeticException("Attempting to add "
+ "positive and negative infinity.");
//return (T) (Double) Double.NaN;
} else {
return (T) x0;
}
} else {
BigDecimal x1 = BigDecimal.valueOf(x0);
BigDecimal y1 = BigDecimal.valueOf(y0);
BigDecimal sum = x1.add(y1);
testDouble(sum);
return (T) (Double) sum.doubleValue();
}
} else if (x instanceof Float) {
Float x0 = (Float) x;
// Deal with special cases.
if (x0.isNaN()) {
return (T) x0;
}
Float y0 = (Float) y;
if (y0.isNaN()) {
return (T) y0;
}
if (x0 == Float.POSITIVE_INFINITY) {
if (y0 == Float.NEGATIVE_INFINITY) {
throw new ArithmeticException("Attempting to add "
+ "positive and negative infinity.");
//return (T) (Float) Float.NaN;
} else {
return (T) x0;
}
} else if (x0 == Float.NEGATIVE_INFINITY) {
if (y0 == Float.POSITIVE_INFINITY) {
throw new ArithmeticException("Attempting to add "
+ "positive and negative infinity.");
//return (T) (Float) Float.NaN;
} else {
return (T) x0;
}
} else {
BigDecimal x1 = BigDecimal.valueOf(x0);
BigDecimal y1 = BigDecimal.valueOf(y0);
BigDecimal sum = x1.add(y1);
testFloat(sum);
return (T) (Float) sum.floatValue();
}
} else if (x instanceof Long) {
BigInteger x0 = BigInteger.valueOf((Long) x);
BigInteger y0 = BigInteger.valueOf((Long) y);
return (T) (Long) x0.add(y0).longValueExact();
} else if (x instanceof Integer) {
BigInteger x0 = BigInteger.valueOf((Integer) x);
BigInteger y0 = BigInteger.valueOf((Integer) y);
return (T) (Integer) x0.add(y0).intValueExact();
} else if (x instanceof Short) {
BigInteger x0 = BigInteger.valueOf((Short) x);
BigInteger y0 = BigInteger.valueOf((Short) y);
return (T) (Short) x0.add(y0).shortValueExact();
} else if (x instanceof Byte) {
BigInteger x0 = BigInteger.valueOf((Byte) x);
BigInteger y0 = BigInteger.valueOf((Byte) y);
return (T) (Byte) x0.add(y0).byteValueExact();
} else {
throw new IllegalArgumentException("Type T=" + x.getClass()
+ " is not supported in Generic_Collections.add(T, T)");
}
}
}
/**
* For adding two generic Numbers of the same type. The types of number are
* converted as appropriate into BigDecimals or BigIntegers (for integer
* type numbers and floating point number respectively - if they are not
* already of these types) which are then added and the result cast into the
* type T. If the result of adding the two numbers cannot be stored exactly
* in the case of integer type numerical addition then an
* ArithmeticException is thrown.
*
* If the result of adding the two numbers is beyond the range in T1 then an
* ArithmeticExcpetion is thrown unless infinities are involved (except when
* the two numbers being added are opposite infinities - in which case an
* ArithmeticException is thrown). If one number is positive or negative
* infinity then that infinity is returned. In cases where the values being
* added are represented in floating point precision the results are a
* consequence of a narrowing digital conversion. (N.B. If desirable then if
* numbers do not increase or decrease as expected then there could be an
* implementation that throws an ArithmeticException in cases where a
* narrowing digital conversion does not result in a larger or smaller
* number as is typically mathematically expected in a sum.
*
* @param The type of the Number x and the result returned.
* @param The type of the Number y.
* @param x A Number to add.
* @param y A Number to add.
* @return The result of adding x and y expressed in the same type as x.
*/
public static T1 add2(T1 x, T2 y) {
if (x == null || y == null) {
return null;
}
if (x instanceof BigDecimal) {
BigDecimal x0 = (BigDecimal) x;
if (y instanceof BigDecimal) {
return (T1) x0.add((BigDecimal) y);
} else if (y instanceof BigInteger) {
return (T1) x0.add(new BigDecimal((BigInteger) y));
} else if (y instanceof Double) {
return (T1) x0.add(new BigDecimal((Double) y));
} else if (y instanceof Float) {
return (T1) x0.add(new BigDecimal((Float) y));
} else if (y instanceof Long) {
return (T1) x0.add(new BigDecimal((Long) y));
} else if (y instanceof Integer) {
return (T1) x0.add(new BigDecimal((Integer) y));
} else if (y instanceof Short) {
return (T1) x0.add(new BigDecimal((Short) y));
} else if (y instanceof Byte) {
return (T1) x0.add(new BigDecimal((Byte) y));
} else {
throw new IllegalArgumentException("Type T2=" + y.getClass()
+ " is not supported in Generic_Math.add(T1, T2)");
}
} else if (x instanceof BigInteger) {
BigInteger x0 = (BigInteger) x;
if (y instanceof BigDecimal) {
return (T1) x0.add(((BigDecimal) y).toBigInteger());
} else if (y instanceof BigInteger) {
return (T1) x0.add((BigInteger) y);
} else if (y instanceof Double) {
return (T1) x0.add(BigInteger.valueOf(((Double) y).longValue()));
} else if (y instanceof Float) {
return (T1) x0.add(BigInteger.valueOf(((Float) y).longValue()));
} else if (y instanceof Long) {
return (T1) x0.add(BigInteger.valueOf((Long) y));
} else if (y instanceof Integer) {
return (T1) x0.add(BigInteger.valueOf((Integer) y));
} else if (y instanceof Short) {
return (T1) x0.add(BigInteger.valueOf((Short) y));
} else if (y instanceof Byte) {
return (T1) x0.add(BigInteger.valueOf((Byte) y));
} else {
throw new IllegalArgumentException("Type T2=" + y.getClass()
+ " is not supported in Generic_Math.add(T1, T2)");
}
} else if (x instanceof Double) {
Double x0 = (Double) x;
// Deal with special cases.
if (x0.isNaN()) {
return (T1) x0;
}
if (y instanceof Double) {
Double y0 = (Double) y;
if (y0.isNaN()) {
return (T1) (Double) Double.NaN;
}
} else if (y instanceof Float) {
Float y0 = (Float) y;
if (y0.isNaN()) {
return (T1) (Double) Double.NaN;
}
}
if (x0 == Double.POSITIVE_INFINITY) {
if (y instanceof Double) {
Double y0 = (Double) y;
if (y0 == Double.NEGATIVE_INFINITY) {
throw new ArithmeticException("Attempting to add "
+ "positive and negative infinity.");
//return (T1) (Double) Double.NaN;
} else {
return (T1) x0;
}
} else if (y instanceof Float) {
Float y0 = (Float) y;
if (y0 == Float.NEGATIVE_INFINITY) {
throw new ArithmeticException("Attempting to add "
+ "positive and negative infinity.");
//return (T1) (Double) Double.NaN;
} else {
return (T1) x0;
}
} else {
return (T1) x0;
}
} else if (x0 == Double.NEGATIVE_INFINITY) {
if (y instanceof Double) {
Double y0 = (Double) y;
if (y0 == Double.POSITIVE_INFINITY) {
throw new ArithmeticException("Attempting to add "
+ "positive and negative infinity.");
//return (T1) (Double) Double.NaN;
} else {
return (T1) x0;
}
} else if (y instanceof Float) {
Float y0 = (Float) y;
if (y0 == Float.POSITIVE_INFINITY) {
throw new ArithmeticException("Attempting to add "
+ "positive and negative infinity.");
//return (T1) (Double) Double.NaN;
} else {
return (T1) x0;
}
} else {
return (T1) x0;
}
} else {
BigDecimal x1 = BigDecimal.valueOf(x0);
if (y instanceof BigDecimal) {
BigDecimal sum = x1.add((BigDecimal) y);
testDouble(sum);
return (T1) (Double) sum.doubleValue();
} else if (y instanceof BigInteger) {
BigDecimal sum = x1.add(new BigDecimal((BigInteger) y));
testDouble(sum);
return (T1) (Double) sum.doubleValue();
} else if (y instanceof Double) {
BigDecimal sum = x1.add(new BigDecimal((Double) y));
testDouble(sum);
return (T1) (Double) sum.doubleValue();
} else if (y instanceof Float) {
BigDecimal sum = x1.add(new BigDecimal((Float) y));
testDouble(sum);
return (T1) (Double) sum.doubleValue();
} else if (y instanceof Long) {
BigDecimal sum = x1.add(new BigDecimal((Long) y));
testDouble(sum);
return (T1) (Double) sum.doubleValue();
} else if (y instanceof Integer) {
BigDecimal sum = x1.add(new BigDecimal((Integer) y));
testDouble(sum);
return (T1) (Double) sum.doubleValue();
} else if (y instanceof Short) {
BigDecimal sum = x1.add(new BigDecimal((Short) y));
testDouble(sum);
return (T1) (Double) sum.doubleValue();
} else if (y instanceof Byte) {
BigDecimal sum = x1.add(new BigDecimal((Byte) y));
testDouble(sum);
return (T1) (Double) sum.doubleValue();
} else {
throw new IllegalArgumentException("Type T2=" + y.getClass()
+ " is not supported in Generic_Math.add(T1, T2)");
}
}
} else if (x instanceof Float) {
Float x0 = (Float) x;
// Deal with special cases.
if (x0.isNaN()) {
return (T1) x0;
}
if (y instanceof Double) {
Double y0 = (Double) y;
if (y0.isNaN()) {
return (T1) (Float) Float.NaN;
}
} else if (y instanceof Float) {
Float y0 = (Float) y;
if (y0.isNaN()) {
return (T1) (Float) Float.NaN;
}
}
if (x0 == Float.POSITIVE_INFINITY) {
if (y instanceof Double) {
Double y0 = (Double) y;
if (y0 == Double.NEGATIVE_INFINITY) {
throw new ArithmeticException("Attempting to add "
+ "positive and negative infinity.");
//return (T1) (Float) Float.NaN;
} else {
return (T1) x0;
}
} else if (y instanceof Float) {
Float y0 = (Float) y;
if (y0 == Float.NEGATIVE_INFINITY) {
throw new ArithmeticException("Attempting to add "
+ "positive and negative infinity.");
//return (T1) (Float) Float.NaN;
} else {
return (T1) x0;
}
} else {
return (T1) x0;
}
} else if (x0 == Float.NEGATIVE_INFINITY) {
if (y instanceof Double) {
Double y0 = (Double) y;
if (y0 == Double.POSITIVE_INFINITY) {
throw new ArithmeticException("Attempting to add "
+ "positive and negative infinity.");
//return (T1) (Float) Float.NaN;
} else {
return (T1) x0;
}
} else if (y instanceof Float) {
Float y0 = (Float) y;
if (y0 == Float.POSITIVE_INFINITY) {
throw new ArithmeticException("Attempting to add "
+ "positive and negative infinity.");
//return (T1) (Float) Float.NaN;
} else {
return (T1) x0;
}
} else {
return (T1) x0;
}
} else {
BigDecimal x1 = BigDecimal.valueOf(x0);
if (y instanceof BigDecimal) {
BigDecimal sum = x1.add((BigDecimal) y);
testFloat(sum);
return (T1) (Float) sum.floatValue();
} else if (y instanceof BigInteger) {
BigDecimal sum = x1.add(new BigDecimal((BigInteger) y));
testFloat(sum);
return (T1) (Float) sum.floatValue();
} else if (y instanceof Double) {
BigDecimal sum = x1.add(new BigDecimal((Double) y));
testFloat(sum);
return (T1) (Float) sum.floatValue();
} else if (y instanceof Float) {
BigDecimal sum = x1.add(new BigDecimal((Float) y));
testFloat(sum);
return (T1) (Float) sum.floatValue();
} else if (y instanceof Long) {
BigDecimal sum = x1.add(new BigDecimal((Long) y));
testFloat(sum);
return (T1) (Float) sum.floatValue();
} else if (y instanceof Integer) {
BigDecimal sum = x1.add(new BigDecimal((Integer) y));
testFloat(sum);
return (T1) (Float) sum.floatValue();
} else if (y instanceof Short) {
BigDecimal sum = x1.add(new BigDecimal((Short) y));
testFloat(sum);
return (T1) (Float) sum.floatValue();
} else if (y instanceof Byte) {
BigDecimal sum = x1.add(new BigDecimal((Byte) y));
testFloat(sum);
return (T1) (Float) sum.floatValue();
} else {
throw new IllegalArgumentException("Type T2=" + y.getClass()
+ " is not supported in Generic_Math.add(T1, T2)");
}
}
} else if (x instanceof Long) {
Long x0 = (Long) x;
// Deal with special cases.
if (y instanceof Double) {
Double y0 = (Double) y;
if (y0.isNaN()) {
throw new ArithmeticException("T1 is type Long and T2 is "
+ "Double and NaN in Generic_Math.add(T1, T2)");
} else {
BigInteger x1 = BigInteger.valueOf(x0);
return (T1) (Long) x1.add((new BigDecimal((Double) y))
.toBigInteger()).longValueExact();
}
} else if (y instanceof Float) {
Float y0 = (Float) y;
if (y0.isNaN()) {
throw new ArithmeticException("T1 is type Long and T2 is "
+ "Float and NaN in Generic_Math.add(T1, T2)");
} else {
BigInteger x1 = BigInteger.valueOf(x0);
return (T1) (Long) x1.add((new BigDecimal((Float) y))
.toBigInteger()).longValueExact();
}
} else {
BigInteger x1 = BigInteger.valueOf(x0);
if (y instanceof BigDecimal) {
return (T1) (Long) x1.add(((BigDecimal) y).toBigInteger())
.longValueExact();
} else if (y instanceof BigInteger) {
return (T1) (Long) x1.add((BigInteger) y).longValueExact();
} else if (y instanceof Long) {
return (T1) (Long) x1.add(BigInteger.valueOf((Long) y))
.longValueExact();
} else if (y instanceof Integer) {
return (T1) (Long) x1.add(BigInteger.valueOf((Integer) y))
.longValueExact();
} else if (y instanceof Short) {
return (T1) (Long) x1.add(BigInteger.valueOf((Short) y))
.longValueExact();
} else if (y instanceof Byte) {
return (T1) (Long) x1.add(BigInteger.valueOf((Byte) y))
.longValueExact();
} else {
throw new IllegalArgumentException("Type T2=" + y.getClass()
+ " is not supported in Generic_Math.add(T1, T2)");
}
}
} else if (x instanceof Integer) {
Integer x0 = (Integer) x;
// Deal with special cases.
if (y instanceof Double) {
Double y0 = (Double) y;
if (y0.isNaN()) {
throw new ArithmeticException("T1 is type Integer and T2 is"
+ " Double and NaN in Generic_Math.add(T1, T2)");
} else {
BigInteger x1 = BigInteger.valueOf(x0);
return (T1) (Integer) x1.add((new BigDecimal((Double) y))
.toBigInteger()).intValueExact();
}
} else if (y instanceof Float) {
Float y0 = (Float) y;
if (y0.isNaN()) {
throw new ArithmeticException("T1 is type Integer and T2 is"
+ " Float and NaN in Generic_Math.add(T1, T2)");
} else {
BigInteger x1 = BigInteger.valueOf(x0);
return (T1) (Integer) x1.add((new BigDecimal((Float) y))
.toBigInteger()).intValueExact();
}
} else {
BigInteger x1 = BigInteger.valueOf(x0);
if (y instanceof BigDecimal) {
return (T1) (Integer) x1.add(((BigDecimal) y).
toBigInteger()).intValueExact();
} else if (y instanceof BigInteger) {
return (T1) (Integer) x1.add((BigInteger) y).intValueExact();
} else if (y instanceof Long) {
return (T1) (Integer) x1.add(BigInteger.valueOf((Long) y))
.intValueExact();
} else if (y instanceof Integer) {
return (T1) (Integer) x1.add(BigInteger.valueOf((Integer) y))
.intValueExact();
} else if (y instanceof Short) {
return (T1) (Integer) x1.add(BigInteger.valueOf((Short) y))
.intValueExact();
} else if (y instanceof Byte) {
return (T1) (Integer) x1.add(BigInteger.valueOf((Byte) y))
.intValueExact();
} else {
throw new IllegalArgumentException("Type T2=" + y.getClass()
+ " is not supported in Generic_Math.add(T1, T2)");
}
}
} else if (x instanceof Short) {
Short x0 = (Short) x;
// Deal with special cases.
if (y instanceof Double) {
Double y0 = (Double) y;
if (y0.isNaN()) {
throw new ArithmeticException("T1 is type Short and T2 is"
+ " Double and NaN in Generic_Math.add(T1, T2)");
} else if (y instanceof Double) {
BigInteger x1 = BigInteger.valueOf(x0);
return (T1) (Short) x1.add((new BigDecimal((Double) y))
.toBigInteger()).shortValueExact();
}
} else if (y instanceof Float) {
Float y0 = (Float) y;
if (y0.isNaN()) {
throw new ArithmeticException("T1 is type Short and T2 is"
+ " Float and NaN in Generic_Math.add(T1, T2)");
} else {
BigInteger x1 = BigInteger.valueOf(x0);
return (T1) (Short) x1.add((new BigDecimal((Float) y))
.toBigInteger()).shortValueExact();
}
} else {
BigInteger x1 = BigInteger.valueOf(x0);
if (y instanceof BigDecimal) {
return (T1) (Short) x1.add(((BigDecimal) y).toBigInteger())
.shortValueExact();
} else if (y instanceof BigInteger) {
return (T1) (Short) x1.add((BigInteger) y).shortValueExact();
} else if (y instanceof Long) {
return (T1) (Short) x1.add(BigInteger.valueOf((Long) y))
.shortValueExact();
} else if (y instanceof Integer) {
return (T1) (Short) x1.add(BigInteger.valueOf((Integer) y))
.shortValueExact();
} else if (y instanceof Short) {
return (T1) (Short) x1.add(BigInteger.valueOf((Short) y))
.shortValueExact();
} else if (y instanceof Byte) {
return (T1) (Short) x1.add(BigInteger.valueOf((Byte) y))
.shortValueExact();
} else {
throw new IllegalArgumentException("Type T2=" + y.getClass()
+ " is not supported in Generic_Math.add(T1, T2)");
}
}
} else if (x instanceof Byte) {
Byte x0 = (Byte) x;
// Deal with special cases.
if (y instanceof Double) {
Double y0 = (Double) y;
if (y0.isNaN()) {
throw new ArithmeticException("T1 is type Byte and T2 is"
+ " Double and NaN in Generic_Math.add(T1, T2)");
} else {
BigInteger x1 = BigInteger.valueOf(x0);
return (T1) (Byte) x1.add((new BigDecimal((Double) y))
.toBigInteger()).byteValueExact();
}
} else if (y instanceof Float) {
Float y0 = (Float) y;
if (y0.isNaN()) {
throw new ArithmeticException("T1 is type Byte and T2 is"
+ " Float and NaN in Generic_Math.add(T1, T2)");
} else {
BigInteger x1 = BigInteger.valueOf(x0);
return (T1) (Byte) x1.add((new BigDecimal((Float) y))
.toBigInteger()).byteValueExact();
}
} else {
BigInteger x1 = BigInteger.valueOf(x0);
if (y instanceof BigDecimal) {
return (T1) (Byte) x1.add(((BigDecimal) y).toBigInteger())
.byteValueExact();
} else if (y instanceof BigInteger) {
return (T1) (Byte) x1.add((BigInteger) y).byteValueExact();
} else if (y instanceof Long) {
return (T1) (Byte) x1.add(BigInteger.valueOf((Long) y))
.byteValueExact();
} else if (y instanceof Integer) {
return (T1) (Byte) x1.add(BigInteger.valueOf((Integer) y))
.byteValueExact();
} else if (y instanceof Short) {
return (T1) (Byte) x1.add(BigInteger.valueOf((Short) y))
.byteValueExact();
} else if (y instanceof Byte) {
return (T1) (Byte) x1.add(BigInteger.valueOf((Byte) y))
.byteValueExact();
} else {
throw new IllegalArgumentException("Type T2=" + y.getClass()
+ " is not supported in Generic_Math.add(T1, T2)");
}
}
} else {
throw new IllegalArgumentException("Type T=" + x.getClass()
+ " is not supported in Generic_Collections.add(T, T)");
}
// This line should never be reached!
return null;
}
/**
* @param x Value to test.
* @throws ArithmeticException if x is greater than {@link #DOUBLE_MAXVALUE}
* or less than {@link #DOUBLE_MAXVALUE_NEG}.
*/
public static void testDouble(BigDecimal x) {
if (x.compareTo(DOUBLE_MAXVALUE) == 1) {
throw new ArithmeticException("x " + x.toString() + " is greater "
+ "than Double.Max_Value.");
}
if (x.compareTo(DOUBLE_MAXVALUE_NEG) == -1) {
throw new ArithmeticException("x " + x.toString() + " is less "
+ "than -Double.Max_Value.");
}
}
/**
* @param x Value to test.
* @throws ArithmeticException if x is greater than {@link #FLOAT_MAXVALUE}
* or less than {@link #FLOAT_MAXVALUE_NEG}.
*/
public static void testFloat(BigDecimal x) {
if (x.compareTo(FLOAT_MAXVALUE) == 1) {
throw new ArithmeticException("x " + x.toString() + " is greater "
+ "than Float.Max_Value.");
}
if (x.compareTo(FLOAT_MAXVALUE_NEG) == -1) {
throw new ArithmeticException("x " + x.toString() + " is less "
+ "than -Float.Max_Value.");
}
}
/**
* Tests if x can be represented within epsilon as a double. Choose epsilon
* equal to BigDecimal.ZERO to test 100% accuracy.
*
* @param x Number to test.
* @param epsilon The allowed range either side of x for the double
* representation.
* @return -1 if x cannot be represented as a double within epsilon and the
* nearest representation is less than x; 1 if x cannot be represented as a
* double within epsilon and the nearest representation is greater than x; 0
* otherwise.
*/
public static int testDouble(BigDecimal x, BigDecimal epsilon) {
double xd = x.doubleValue();
//double xd = Double.valueOf(x.toString());
//System.out.println(xd);
//System.out.println(Double.toString(xd));
/**
* Simply using:
*
* BigDecimal xToCompare = new BigDecimal(xd);
*
* Fails!
*
* Precision needs to be handled explicitly.
*/
BigDecimal xToCompare = new BigDecimal(Double.toString(xd),
getMathContextForComparison(x));
return compare(x, xToCompare, epsilon);
}
/**
* Compares x and xd. If the difference is greater than epsilon then -1 is
* returned if x is less than xd.subtract(epsilon), 1 is returned if x is
* greater than xd.add(epsilon); 0 otherwise (i.e. x and xd are within
* epsilon).
*
* @param x A number to compare.
* @param xd A number to compare.
* @param epsilon The allowed error epsilon.
* @return -1 if x is less than xd.subtract(epsilon), 1 if x is greater than
* xd.add(epsilon) and 0 otherwise.
*/
public static int compare(BigDecimal x, BigDecimal xd, BigDecimal epsilon) {
if (x.compareTo(xd.subtract(epsilon)) == -1) {
return -1;
}
if (x.compareTo(xd.add(epsilon)) == 1) {
return 1;
}
return 0;
}
/**
* Tests if x can be represented within epsilon as a double. Choose epsilon
* equal to BigDecimal.ZERO to test 100% accuracy.
*
* @param x Number to test.
* @param epsilon The allowed range either side of x for the double
* representation.
* @return false if x cannot be represented as a double within epsilon; true
* otherwise.
*/
public static boolean testDouble2(BigDecimal x, BigDecimal epsilon) {
double xd = x.doubleValue();
//double xd = Double.valueOf(x.toString());
//System.out.println(xd);
//System.out.println(Double.toString(xd));
/**
* Simply using:
*
* BigDecimal xToCompare = new BigDecimal(xd);
*
* Fails!
*
* Precision needs to be handled explicitly.
*/
BigDecimal xToCompare = new BigDecimal(Double.toString(xd),
getMathContextForComparison(x));
return compare2(x, xToCompare, epsilon);
}
/**
* For getting a MathContext for {@code x} for comparison purposes.
* @param x A BigDecimal.
* @return A MathContext.
*/
public static MathContext getMathContextForComparison(BigDecimal x) {
int ul = x.unscaledValue().toString().length();
// 2 is added to precision in the MathContext to cope with any rounding.
MathContext mc = new MathContext(
ul + (int) Math.pow(10, ul) + x.scale() + 2, // Precision.
RoundingMode.FLOOR);
return mc;
}
/**
* Use x.precision() instead.
* @param x A BigDecimal.
* @return An integer representing the precision of {@code x}.
* @deprecated As of Version 1.1 - this is likely to removed in a future
* release.
*/
@Deprecated
public static int getPrecision(BigDecimal x) {
int ul = x.unscaledValue().toString().length();
return ul + (int) Math.pow(10, ul) + x.scale();
}
/**
* {@code x.precision() + 2}
* @param x A BigDecimal.
* @return An integer representing the precision of {@code x}.
*/
public static int getPrecisionSafe(BigDecimal x) {
return x.precision() + 2;
//return getPrecision(x) + 2;
}
/**
* Compares x and xd. If the difference is greater than epsilon then false
* is returned. Otherwise true is returned.
*
* @param x A number to compare.
* @param xd A number to compare.
* @param epsilon The allowed error epsilon.
* @return true if x is less than xd.add(epsilon) and greater than
* xd.subtract(epsilon) and false otherwise.
*/
public static boolean compare2(BigDecimal x, BigDecimal xd, BigDecimal epsilon) {
if (x.compareTo(xd.subtract(epsilon)) == -1) {
return false;
}
return x.compareTo(xd.add(epsilon)) != 1;
}
/**
* Tests if x can be represented within epsilon as a float. Choose epsilon
* equal to BigDecimal.ZERO to test 100% accuracy.
*
* @param x Number to test.
* @param epsilon The allowed range either side of x for the float
* representation.
* @return -1 if x cannot be represented as a float within epsilon and the
* nearest representation is less than x; 1 if x cannot be represented as a
* float within epsilon and the nearest representation is greater than x; 0
* otherwise.
*/
public static int testFloat(BigDecimal x, BigDecimal epsilon) {
float xd = x.floatValue();
return compare(x, new BigDecimal(xd), epsilon);
}
/**
* Tests if x can be represented within epsilon as a float. Choose epsilon
* equal to BigDecimal.ZERO to test 100% accuracy.
*
* @param x Number to test.
* @param epsilon The allowed range either side of x for the float
* representation.
* @return false if x cannot be represented as a float within epsilon; true
* otherwise.
*/
public static boolean testFloat2(BigDecimal x, BigDecimal epsilon) {
float xd = x.floatValue();
//float xd = Float.valueOf(x.toString());
//System.out.println(xd);
//System.out.println(Float.toString(xd));
/**
* Simply using:
*
* BigDecimal xToCompare = new BigDecimal(xd);
*
* Fails!
*
* Precision needs to be handled explicitly.
*/
BigDecimal xToCompare = new BigDecimal(Float.toString(xd),
getMathContextForComparison(x));
return compare2(x, xToCompare, epsilon);
}
}
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