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 * (the "License"); you may not use this file except in compliance with
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package org.apache.commons.math3.transform;

import org.apache.commons.math3.analysis.UnivariateFunction;
import org.apache.commons.math3.exception.MathIllegalArgumentException;
import org.apache.commons.math3.exception.NonMonotonicSequenceException;
import org.apache.commons.math3.exception.NotStrictlyPositiveException;

Interface for one-dimensional data sets transformations producing real results.
 Such transforms include sine transform, cosine transform or Hadamard transform. 
Fourier transform is of a different kind and does not implement this interface since it produces Complex results instead of real ones. 
Since:
2.0/**
 * Interface for one-dimensional data sets transformations producing real results.
 * <p>
 * Such transforms include {@link FastSineTransformer sine transform},
 * {@link FastCosineTransformer cosine transform} or {@link
 * FastHadamardTransformer Hadamard transform}. {@link FastFourierTransformer
 * Fourier transform} is of a different kind and does not implement this
 * interface since it produces {@link org.apache.commons.math3.complex.Complex}
 * results instead of real ones.
 *
 * @since 2.0
 */
public interface RealTransformer  {

    
Returns the (forward, inverse) transform of the specified real data set.
Params:
f – the real data array to be transformed (signal)
type – the type of transform (forward, inverse) to be performed
Throws:
MathIllegalArgumentException – if the array cannot be transformed
  with the given type (this may be for example due to array size, which is
  constrained in some transforms)
Returns:
the real transformed array (spectrum)/**
     * Returns the (forward, inverse) transform of the specified real data set.
     *
     * @param f the real data array to be transformed (signal)
     * @param type the type of transform (forward, inverse) to be performed
     * @return the real transformed array (spectrum)
     * @throws MathIllegalArgumentException if the array cannot be transformed
     *   with the given type (this may be for example due to array size, which is
     *   constrained in some transforms)
     */
    double[] transform(double[] f, TransformType type) throws MathIllegalArgumentException;

    
Returns the (forward, inverse) transform of the specified real function,
sampled on the specified interval.
Params:
f – the function to be sampled and transformed
min – the (inclusive) lower bound for the interval
max – the (exclusive) upper bound for the interval
n – the number of sample points
type – the type of transform (forward, inverse) to be performed
Throws:
NonMonotonicSequenceException – if the lower bound is greater than, or equal to the upper bound
NotStrictlyPositiveException – if the number of sample points is negative
MathIllegalArgumentException – if the sample cannot be transformed
  with the given type (this may be for example due to sample size, which is
  constrained in some transforms)
Returns:
the real transformed array/**
     * Returns the (forward, inverse) transform of the specified real function,
     * sampled on the specified interval.
     *
     * @param f the function to be sampled and transformed
     * @param min the (inclusive) lower bound for the interval
     * @param max the (exclusive) upper bound for the interval
     * @param n the number of sample points
     * @param type the type of transform (forward, inverse) to be performed
     * @return the real transformed array
     * @throws NonMonotonicSequenceException if the lower bound is greater than, or equal to the upper bound
     * @throws NotStrictlyPositiveException if the number of sample points is negative
     * @throws MathIllegalArgumentException if the sample cannot be transformed
     *   with the given type (this may be for example due to sample size, which is
     *   constrained in some transforms)
     */
    double[] transform(UnivariateFunction f, double min, double max, int n,
                       TransformType type)
        throws NonMonotonicSequenceException, NotStrictlyPositiveException, MathIllegalArgumentException;

}