Package ffx.numerics.math

Class ScalarMath

java.lang.Object
ffx.numerics.math.ScalarMath
public class ScalarMath extends Object
The ScalarMath class is a simple math library that operates on single variables
Since:
1.0
Author:
Jacob M. Litman, Michael J. Schnieders

  • Method Summary

    Modifier and Type
    Method
    Description
    static double
    b2u(double b)
    b2u
    static long
    binomial(long n, long k)
    binomial
    static long
    doubleFactorial(long n)
    Returns n!!
    static long
    factorial(long n)
    Returns n!
    static double
    fermiFunction(double x)
    Compute 1.0 / (1.0 + exp(x)).
    static double
    mirrorDegrees(double angle)
    Reflect proposed angles to be within 0 and 180 degrees.
    static double
    mirrorRadians(double angle)
    Reflect proposed angles to be within 0 and 180 degrees.
    static double
    mod(double a, double b)
    This is an atypical mod function used by crystallography methods.
    static int
    mod(int a, int b)
    This is an atypical mod function used by crystallography methods.
    static double
    modToRange(double value, double lb, double ub)
    Atypical mod function used to move a value into the range lb <= value < ub, assuming the domain is periodic with a period of (ub - lb).
    static double
    quadForm(double[] v, double[][] mat)
    quadForm
    static double
    u2b(double u)
    u2b

    Methods inherited from class java.lang.Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

  • Method Details

    • b2u

      public static double b2u(double b)
      b2u
      Parameters:
      b - a double.
      Returns:
      a double.

    • binomial

      public static long binomial(long n, long k)
      binomial
      Parameters:
      n - a long.
      k - a long.
      Returns:
      Returns the binomial of (n,k).

    • doubleFactorial

      public static long doubleFactorial(long n)
      Returns n!! Precondition: n .GE. -1 Returning 1 for -1 input is analogous to Maple behavior.
      Parameters:
      n - long.
      Returns:
      Returns the n!!.

    • factorial

      public static long factorial(long n)
      Returns n!
      Precondition: n .GE. 0 and n .LE. 20
      Max long = 9223372036854775807
      20! = 2432902008176640000 is ok.
      21! returns an overflow: -4249290049419214848
      Parameters:
      n - long.
      Returns:
      Returns n!.

    • fermiFunction

      public static double fermiFunction(double x)
      Compute 1.0 / (1.0 + exp(x)).
      Parameters:
      x - Input.
      Returns:
      Returns 1.0 / (1.0 + exp(x)).

    • mod

      public static double mod(double a, double b)
      This is an atypical mod function used by crystallography methods.

      mod

      Parameters:
      a - Value to mod.
      b - Value to mod by.
      Returns:
      Positive a % b.

    • mod

      public static int mod(int a, int b)
      This is an atypical mod function used by crystallography methods.
      Parameters:
      a - an int.
      b - an int.
      Returns:
      an int.

    • modToRange

      public static double modToRange(double value, double lb, double ub)
      Atypical mod function used to move a value into the range lb <= value < ub, assuming the domain is periodic with a period of (ub - lb).
      Parameters:
      value - Value to move between bounds.
      lb - Lower bound.
      ub - Upper bound.
      Returns:
      Returns periodic copy of value, in the range lb <= value < ub.

    • u2b

      public static double u2b(double u)
      u2b
      Parameters:
      u - a double.
      Returns:
      a double.

    • quadForm

      public static double quadForm(double[] v, double[][] mat)
      quadForm
      Parameters:
      v - an array of double.
      mat - an array of double.
      Returns:
      a double.

    • mirrorRadians

      public static double mirrorRadians(double angle)
      Reflect proposed angles to be within 0 and 180 degrees.
      Parameters:
      angle - Proposed angle in radians.
      Returns:
      value of mirrored angle in radians.

    • mirrorDegrees

      public static double mirrorDegrees(double angle)
      Reflect proposed angles to be within 0 and 180 degrees.
      Parameters:
      angle - Proposed angle in radians.
      Returns:
      value of mirrored angle in radians.