Package org.meeuw.math

Class Utils

  • public final class Utils
extends Object
    Author:
    Michiel Meeuwissen

    • Field Summary

      Fields 
      Modifier and Type Field Description
      static String e  
      static String PI
      1000 decimals of pi

    • Method Summary

      All Methods Static Methods Concrete Methods 
      Modifier and Type Method Description
      static boolean isPrime​(int n)
      Simple prime test.
      static int leastSignificantBit​(double doubleValue)
      Given a double value, returns the bit the power of 2 exponent that the least significant bit in the IEEE 754 representation of the double represents.
      static int log10​(double d)
      A crude order of magnitude implemention This is like Math.log10(Mat.abs(d))
      static int log10​(long l)
      A crude order of magnitude implemention This is like Math.log10(Mat.abs(l))
      static ChronoUnit orderOfMagnitude​(Duration stddev)  
      static long positivePow​(@javax.validation.constraints.NotNull long base, @javax.validation.constraints.Min(0L) int i)
      Returns base to the power i, a utility in java.lang.Math for that lacks.
      static long positivePow10​(@javax.validation.constraints.Min(0L) int i)
      Returns 10 to the power i, a utility in java.lang.Math for that lacks.
      static double pow​(double base, int i)
      Returns base to the power i, a utility in java.lang.Math for that lacks.
      static double pow​(int base, int i)
      Returns base to the power i, a utility in java.lang.Math for that lacks.
      static double pow10​(int i)
      Returns 10 to the power i, a utility in java.lang.Math for that lacks.
      static double pow2​(int i)
      Returns 10 to the power i, a utility in java.lang.Math for that lacks.
      static Duration round​(Duration duration, ChronoUnit order)  
      static Instant round​(Instant instant, ChronoUnit order)  
      static Stream<int[]> stream​(int length)
      Returns an infinite stream of integer arrays of given length It will start with an array with only zeros.
      static <T extends Enum<T>>
      String      		 toString​(T[] values, int[] basic)
      Given an array of enums, and a array of integers, interpret the second array as exponents for the first one, and create a string representation of that using superscript notation.
      static double uncertaintyForDouble​(double doubleValue)  

    • Method Detail

      • pow10

        public static double pow10​(int i)
        Returns 10 to the power i, a utility in java.lang.Math for that lacks.

      • pow2

        public static double pow2​(int i)
        Returns 10 to the power i, a utility in java.lang.Math for that lacks.

      • pow

        public static double pow​(int base,
                         int i)
        Returns base to the power i, a utility in java.lang.Math for that lacks.

      • pow

        public static double pow​(double base,
                         int i)
        Returns base to the power i, a utility in java.lang.Math for that lacks.

      • positivePow10

        public static long positivePow10​(@Min(0L)
                                 @javax.validation.constraints.Min(0L) int i)
        Returns 10 to the power i, a utility in java.lang.Math for that lacks.
        See Also:
        positivePow(long, int)

      • positivePow

        public static long positivePow​(@NotNull
                               @javax.validation.constraints.NotNull long base,
                               @Min(0L)
                               @javax.validation.constraints.Min(0L) int i)
        Returns base to the power i, a utility in java.lang.Math for that lacks. This is more exact than Math.pow(double, double) (though probably not faster)

      • log10

        public static int log10​(double d)
        A crude order of magnitude implemention This is like Math.log10(Mat.abs(d))

      • log10

        public static int log10​(long l)
        A crude order of magnitude implemention This is like Math.log10(Mat.abs(l))

      • stream

        public static Stream<int[]> stream​(int length)
        Returns an infinite stream of integer arrays of given length It will start with an array with only zeros. Then it will return array filled with all possible combinations of -1, 0, 1, then with all possibles arrays with only -2, -1, 0, 1, 2 and so on.

      • toString

        public static <T extends Enum<T>> String toString​(T[] values,
                                                  int[] basic)
        Given an array of enums, and a array of integers, interpret the second array as exponents for the first one, and create a string representation of that using superscript notation.

      • leastSignificantBit

        public static int leastSignificantBit​(double doubleValue)
        Given a double value, returns the bit the power of 2 exponent that the least significant bit in the IEEE 754 representation of the double represents. pow(2, ) is an estimate of the 'uncertainty' in this double. More precision it simply cannot represent.

      • uncertaintyForDouble

        public static double uncertaintyForDouble​(double doubleValue)

      • isPrime

        public static boolean isPrime​(int n)
        Simple prime test. 6k ± 1 optimization only. Not suitable for (very) large numbers.