Loris::FourierTransform Class Reference

FourierTransform provides a simplified interface to the FFTW library (www.fftw.org). More...

#include <FourierTransform.h>

List of all members.

Public Types
typedef std::vector< std::complex< double > >::size_type	size_type
	An unsigned integral type large enough to represent the length of any transform.
typedef std::vector< std::complex< double > >::iterator	iterator
	The type of a non-const iterator of (complex) transform samples.
typedef std::vector< std::complex< double > >::const_iterator	const_iterator
	The type of a const iterator of (complex) transform samples.
Public Member Functions
	FourierTransform (size_type len)
	Exceptions: RuntimeError  if the necessary buffers cannot be allocated, or there is an error configuring FFTW.
	FourierTransform (const FourierTransform &rhs)
	Initialize a new FourierTransform that is a copy of another, having the same size and the same buffer contents.
	~FourierTransform (void)
	Free the resources associated with this FourierTransform.
FourierTransform &	operator= (const FourierTransform &rhs)
	Make this FourierTransform a copy of another, having the same size and buffer contents.
std::complex< double > &	operator[] (size_type index)
	Access (read/write) a transform sample by index.
const std::complex< double > &	operator[] (size_type index) const
	Access (read-only) a transform sample by index.
iterator	begin (void)
	Return an iterator refering to the beginning of the sequence of complex samples in the transform buffer.
iterator	end (void)
	complex samples in the transform buffer.
const_iterator	begin (void) const
	Return a const iterator refering to the beginning of the sequence of complex samples in the transform buffer.
const_iterator	end (void) const
	complex samples in the transform buffer.
void	transform (void)
	Compute the Fourier transform of the samples stored in the transform buffer.
size_type	size (void) const
	Return the length of the transform (in samples).

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Detailed Description

FourierTransform provides a simplified interface to the FFTW library (www.fftw.org).

Loris uses the FFTW library to perform efficient Fourier transforms of arbitrary length. Clients store and access the in-place transform data as a sequence of std::complex< double >. Samples are stored in the FourierTransform instance using subscript or iterator access, the transform is computed by the transform member, and the transformed samples replace the input samples, and are accessed by subscript or iterator. FourierTransform computes a complex transform, so it can be used to invert a transform of real samples as well. Uses the standard library complex class, which implements arithmetic operations. Does not use FFTW "wisdom" to speed up transform computation.

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Constructor & Destructor Documentation

Loris::FourierTransform::FourierTransform (  const FourierTransform &  rhs  )

Initialize a new FourierTransform that is a copy of another, having the same size and the same buffer contents. Parameters: rhs  is the instance to copy Exceptions: RuntimeError  if the necessary buffers cannot be allocated, or there is an error configuring FFTW.

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Member Function Documentation

const_iterator Loris::FourierTransform::begin (  void   )  const

Return a const iterator refering to the beginning of the sequence of complex samples in the transform buffer. Returns: a const iterator refering to the first position in the transform buffer.

iterator Loris::FourierTransform::begin (  void   )

Return an iterator refering to the beginning of the sequence of complex samples in the transform buffer. Returns: a non-const iterator refering to the first position in the transform buffer.

const_iterator Loris::FourierTransform::end (  void   )  const

complex samples in the transform buffer. Returns: a const iterator refering to one past the last position in the transform buffer.

iterator Loris::FourierTransform::end (  void   )

complex samples in the transform buffer. Returns: a non-const iterator refering to one past the last position in the transform buffer.

FourierTransform& Loris::FourierTransform::operator= (  const FourierTransform &  rhs  )

Make this FourierTransform a copy of another, having the same size and buffer contents. Parameters: rhs  is the instance to copy Returns: a refernce to this instance Exceptions: RuntimeError  if the necessary buffers cannot be allocated, or there is an error configuring FFTW.

const std::complex< double >& Loris::FourierTransform::operator[] (  size_type  index  )  const

Access (read-only) a transform sample by index. Use this member to fill the transform buffer before computing the transform, and to access the samples after computing the transform. (inlined for speed) Parameters: index  is the index or rank of the complex transform sample to access. Zero is the first position in the buffer. Returns: const reference to the std::complex< double > at the specified position in the buffer.

std::complex< double >& Loris::FourierTransform::operator[] (  size_type  index  )

Access (read/write) a transform sample by index. Use this member to fill the transform buffer before computing the transform, and to access the samples after computing the transform. (inlined for speed) Parameters: index  is the index or rank of the complex transform sample to access. Zero is the first position in the buffer. Returns: non-const reference to the std::complex< double > at the specified position in the buffer.

size_type Loris::FourierTransform::size (  void   )  const

Return the length of the transform (in samples). Returns: the length of the transform in samples.

void Loris::FourierTransform::transform (  void   )

Compute the Fourier transform of the samples stored in the transform buffer. The samples stored in the transform buffer (accessed by index or by iterator) are replaced by the transformed samples, in-place.

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