Package org.apache.commons.math3.transform

Class TransformUtils

java.lang.Object
org.apache.commons.math3.transform.TransformUtils
public class TransformUtils extends Object
Useful functions for the implementation of various transforms.
Since:
3.0

  • Method Details

    • scaleArray

      public static double[] scaleArray(double[] f, double d)
      Multiply every component in the given real array by the given real number. The change is made in place.
      Parameters:
      f - the real array to be scaled
      d - the real scaling coefficient
      Returns:
      a reference to the scaled array

    • scaleArray

      public static Complex[] scaleArray(Complex[] f, double d)
      Multiply every component in the given complex array by the given real number. The change is made in place.
      Parameters:
      f - the complex array to be scaled
      d - the real scaling coefficient
      Returns:
      a reference to the scaled array

    • createRealImaginaryArray

      public static double[][] createRealImaginaryArray(Complex[] dataC)
      Builds a new two dimensional array of double filled with the real and imaginary parts of the specified Complex numbers. In the returned array dataRI, the data is laid out as follows
      • dataRI[0][i] = dataC[i].getReal(),
      • dataRI[1][i] = dataC[i].getImaginary().
      Parameters:
      dataC - the array of Complex data to be transformed
      Returns:
      a two dimensional array filled with the real and imaginary parts of the specified complex input

    • createComplexArray

      public static Complex[] createComplexArray(double[][] dataRI) throws DimensionMismatchException
      Builds a new array of Complex from the specified two dimensional array of real and imaginary parts. In the returned array dataC, the data is laid out as follows
      • dataC[i].getReal() = dataRI[0][i],
      • dataC[i].getImaginary() = dataRI[1][i].
      Parameters:
      dataRI - the array of real and imaginary parts to be transformed
      Returns:
      an array of Complex with specified real and imaginary parts.
      Throws:
      DimensionMismatchException - if the number of rows of the specified array is not two, or the array is not rectangular

    • exactLog2

      public static int exactLog2(int n) throws MathIllegalArgumentException
      Returns the base-2 logarithm of the specified int. Throws an exception if n is not a power of two.
      Parameters:
      n - the int whose base-2 logarithm is to be evaluated
      Returns:
      the base-2 logarithm of n
      Throws:
      MathIllegalArgumentException - if n is not a power of two