com.rapiddweller.common.MathUtil Maven / Gradle / Ivy
Go to download
Show more of this group Show more artifacts with this name
Show all versions of rd-lib-common Show documentation
Show all versions of rd-lib-common Show documentation
'rapiddweller Common' is an open source Java library
forked from Databene Commons by Volker Bergmann.
It provides extensions to the Java core library by utility classes, abstract concepts
and concrete implementations.
/*
* Copyright (C) 2004-2015 Volker Bergmann ([email protected]).
* All rights reserved.
*
* 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 com.rapiddweller.common;
import com.rapiddweller.common.math.IntDoublePair;
import com.rapiddweller.common.math.Segmented;
import java.util.List;
/**
* Provides mathematical utility methods.
*
* @author Volker Bergmann
* @since 0.4.0
*/
public class MathUtil {
/**
* Segment segmented.
*
* @param n the n
* @param period the period
* @return the segmented
*/
public static Segmented segment(int n, int period) {
return new Segmented(n / period, n % period);
}
/**
* Nan to null double.
*
* @param value the value
* @return the double
*/
public static Double nanToNull(double value) {
return (Double.isNaN(value) ? null : value);
}
/**
* Returns the number of digits needed for displaying the postfix values of a number, but at most 7.
*
* @param number the number to examine
* @return the number of digits needed for displaying the postfix values of a number, but at most 7
*/
public static int fractionDigits(double number) {
double x = fraction(number);
int n = 0;
while (x >= 0.0000001 && n < 7) {
n++;
x = fraction(x * 10);
}
return n;
}
/**
* Is integral value boolean.
*
* @param number the number
* @return the boolean
*/
public static boolean isIntegralValue(double number) {
return (Math.IEEEremainder(Math.abs(number), 1) == 0);
}
private static double fraction(double number) {
double value = Math.IEEEremainder(Math.abs(number), 1);
if (value < 0) {
value += 1;
}
return value;
}
/**
* Prefix digit count int.
*
* @param number the number
* @return the int
*/
public static int prefixDigitCount(double number) {
return nonNegativeDigitCount((long) Math.abs(number));
}
/**
* Digit count int.
*
* @param number the number
* @return the int
*/
public static int digitCount(long number) {
return nonNegativeDigitCount(Math.abs(number));
}
private static int nonNegativeDigitCount(long number) {
if (number <= 1) {
return 1;
}
return 1 + (int) Math.log10(number);
}
/**
* Digital root int.
*
* @param i the
* @return the int
*/
public static int digitalRoot(int i) {
Assert.notNegative(i, "number");
int result = i;
do {
result = digitSum(result);
} while (result >= 10);
return result;
}
/**
* Digit sum int.
*
* @param i the
* @return the int
*/
public static int digitSum(int i) {
Assert.notNegative(i, "number");
int tmp = i;
int result = 0;
while (tmp > 0) {
result += tmp % 10;
tmp /= 10;
}
return result;
}
/**
* Weighted sum of sum of digits int.
*
* @param number the number
* @param startIndex the start index
* @param weights the weights
* @return the int
*/
public static int weightedSumOfSumOfDigits(String number, int startIndex, int... weights) {
int sum = 0;
for (int i = 0; i < weights.length; i++) {
sum += MathUtil.digitSum(weights[i] * (number.charAt(startIndex + i) - '0'));
}
return sum;
}
/**
* Weighted sum of digits int.
*
* @param number the number
* @param startIndex the start index
* @param weights the weights
* @return the int
*/
public static int weightedSumOfDigits(CharSequence number, int startIndex, int... weights) {
int sum = 0;
for (int i = 0; i < weights.length; i++) {
sum += weights[i] * (number.charAt(startIndex + i) - '0');
}
return sum;
}
/**
* Range includes boolean.
*
* @param x the x
* @param min the min
* @param max the max
* @return the boolean
*/
public static boolean rangeIncludes(long x, long min, long max) {
return (min <= x && x <= max);
}
/**
* Range includes boolean.
*
* @param x the x
* @param min the min
* @param max the max
* @return the boolean
*/
public static boolean rangeIncludes(double x, double min, double max) {
return (min <= x && x <= max);
}
/**
* Between boolean.
*
* @param x the x
* @param min the min
* @param max the max
* @return the boolean
*/
public static boolean between(long x, long min, long max) {
return (min < x && x < max);
}
/**
* Between boolean.
*
* @param x the x
* @param min the min
* @param max the max
* @return the boolean
*/
public static boolean between(double x, double min, double max) {
return (min < x && x < max);
}
/**
* Sum double.
*
* @param addends the addends
* @return the double
*/
public static Double sum(double[] addends) {
double result = 0;
for (double addend : addends) {
result += addend;
}
return result;
}
/**
* Max int.
*
* @param args the args
* @return the int
*/
public static int max(int... args) {
int result = args[0];
for (int i = 1; i < args.length; i++) {
if (args[i] > result) {
result = args[i];
}
}
return result;
}
/**
* Max double.
*
* @param args the args
* @return the double
*/
public static double max(double... args) {
double result = args[0];
for (int i = 1; i < args.length; i++) {
if (args[i] > result) {
result = args[i];
}
}
return result;
}
/**
* Min double.
*
* @param args the args
* @return the double
*/
public static double min(double... args) {
double result = args[0];
for (int i = 1; i < args.length; i++) {
if (args[i] < result) {
result = args[i];
}
}
return result;
}
/**
* Nullable product double.
*
* @param factors the factors
* @return the double
*/
public static Double nullableProduct(Double... factors) {
if (factors.length == 0 || factors[0] == null) {
return null;
}
Double result = factors[0];
for (int i = 1; i < factors.length; i++) {
Double factor = factors[i];
if (factor == null) {
return null;
}
result *= factor;
}
return result;
}
/**
* Nullable division double.
*
* @param dividend the dividend
* @param divisors the divisors
* @return the double
*/
public static Double nullableDivision(Double dividend, Double... divisors) {
if (dividend == null || divisors.length == 0 || divisors[0] == null) {
return null;
}
Double result = dividend;
for (Double divisor : divisors) {
if (divisor == null) {
return null;
}
result /= divisor;
}
return result;
}
/**
* Nullable sum double.
*
* @param summands the summands
* @return the double
*/
public static Double nullableSum(Double... summands) {
if (summands.length == 0 || summands[0] == null) {
return null;
}
Double result = summands[0];
for (int i = 1; i < summands.length; i++) {
Double factor = summands[i];
if (factor == null) {
return null;
}
result += factor;
}
return result;
}
/**
* Nullable subtraction double.
*
* @param minuend the minuend
* @param subtrahends the subtrahends
* @return the double
*/
public static Double nullableSubtraction(Double minuend, Double... subtrahends) {
if (minuend == null || subtrahends.length == 0 || subtrahends[0] == null) {
return null;
}
Double result = minuend;
for (Double divisor : subtrahends) {
if (divisor == null) {
return null;
}
result -= divisor;
}
return result;
}
/**
* Factorial long.
*
* @param n the n
* @return the long
*/
public static long factorial(int n) {
long result = n;
for (int i = n - 1; i > 0; i--) {
result *= i;
}
return result;
}
/**
* Deg to rad double.
*
* @param degree the degree
* @return the double
*/
public static double degToRad(double degree) {
return degree * Math.PI / 180;
}
/**
* Rad to deg double.
*
* @param rad the rad
* @return the double
*/
public static double radToDeg(double rad) {
return rad / Math.PI * 180;
}
/**
* Square double.
*
* @param x the x
* @return the double
*/
public static double square(double x) {
return x * x;
}
/**
* Average double.
*
* @param values the values
* @return the double
*/
public static double average(double[] values) {
double result = 0;
for (double value : values) {
result += value / values.length;
}
return result;
}
/**
* Variance double.
*
* @param values the values
* @return the double
*/
public static double variance(double[] values) {
double avg = average(values);
double weight = 1. / values.length;
double result = 0;
for (double value : values) {
result += weight * square(value - avg);
}
return result;
}
/**
* Standard deviation double.
*
* @param values the values
* @return the double
*/
public static double standardDeviation(double[] values) {
return Math.sqrt(variance(values));
}
/**
* Corrected standard deviation double.
*
* @param values the values
* @return the double
*/
public static double correctedStandardDeviation(double[] values) {
double avg = average(values);
double weight = 1. / (values.length - 1);
double result = 0;
for (double value : values) {
result += weight * square(value - avg);
}
return Math.sqrt(result);
}
/**
* Min value int double pair.
*
* @param values the values
* @return the int double pair
*/
public static IntDoublePair minValue(List values) {
IntDoublePair min = values.get(0);
for (int i = values.size() - 1; i >= 0; i--) {
IntDoublePair tmp = values.get(i);
if (tmp.d < min.d) {
min = tmp;
}
}
return min;
}
/**
* Max value int double pair.
*
* @param values the values
* @return the int double pair
*/
public static IntDoublePair maxValue(List values) {
IntDoublePair max = values.get(0);
for (int i = values.size() - 1; i >= 0; i--) {
IntDoublePair tmp = values.get(i);
if (tmp.d > max.d) {
max = tmp;
}
}
return max;
}
}