Package org.hipparchus.transform

Class TransformUtils

  • public class TransformUtils
extends Object
    Useful functions for the implementation of various transforms.

    • Method Detail

      • 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 MathIllegalArgumentException
        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:
        MathIllegalArgumentException - 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