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| FFTWConvolvePlan< N, Real > Class Template Reference Fast Fourier Transform |

`#include <vigra/multi_fft.hxx>`

List of all members.

## Public Member Functions

template<class C1 , class C2 , class C3 >
void | execute (MultiArrayView< N, Real, C1 > in, MultiArrayView< N, Real, C2 > kernel, MultiArrayView< N, Real, C3 > out)
| Execute a plan to convolve a real array with a real kernel.
template<class C1 , class C2 , class C3 >
void | execute (MultiArrayView< N, Real, C1 > in, MultiArrayView< N, FFTWComplex< Real >, C2 > kernel, MultiArrayView< N, Real, C3 > out)
| Execute a plan to convolve a real array with a complex kernel.
template<class C1 , class C2 , class C3 >
void | execute (MultiArrayView< N, FFTWComplex< Real >, C1 > in, MultiArrayView< N, FFTWComplex< Real >, C2 > kernel, MultiArrayView< N, FFTWComplex< Real >, C3 > out)
| Execute a plan to convolve a complex array with a complex kernel.
template<class C1 , class KernelIterator , class OutIterator >
void | executeMany (MultiArrayView< N, FFTWComplex< Real >, C1 > in, KernelIterator kernels, KernelIterator kernelsEnd, OutIterator outs)
| Execute a plan to convolve a complex array with a sequence of kernels.
template<class C1 , class KernelIterator , class OutIterator >
void | executeMany (MultiArrayView< N, Real, C1 > in, KernelIterator kernels, KernelIterator kernelsEnd, OutIterator outs)
| Execute a plan to convolve a real array with a sequence of kernels.
| FFTWConvolvePlan ()
| Create an empty plan.
template<class C1 , class C2 , class C3 >
| FFTWConvolvePlan (MultiArrayView< N, Real, C1 > in, MultiArrayView< N, Real, C2 > kernel, MultiArrayView< N, Real, C3 > out, unsigned int planner_flags=FFTW_ESTIMATE)
| Create a plan to convolve a real array with a real kernel.
template<class C1 , class C2 , class C3 >
| FFTWConvolvePlan (MultiArrayView< N, Real, C1 > in, MultiArrayView< N, FFTWComplex< Real >, C2 > kernel, MultiArrayView< N, Real, C3 > out, unsigned int planner_flags=FFTW_ESTIMATE)
| Create a plan to convolve a real array with a complex kernel.
template<class C1 , class C2 , class C3 >
| FFTWConvolvePlan (MultiArrayView< N, FFTWComplex< Real >, C1 > in, MultiArrayView< N, FFTWComplex< Real >, C2 > kernel, MultiArrayView< N, FFTWComplex< Real >, C3 > out, bool fourierDomainKernel, unsigned int planner_flags=FFTW_ESTIMATE)
| Create a plan to convolve a complex array with a complex kernel.
template<class C1 , class C2 , class C3 >
| FFTWConvolvePlan (Shape inOut, Shape kernel, bool useFourierKernel=false, unsigned int planner_flags=FFTW_ESTIMATE)
| Create a plan from just the shape information.
template<class C1 , class C2 , class C3 >
void | init (MultiArrayView< N, Real, C1 > in, MultiArrayView< N, Real, C2 > kernel, MultiArrayView< N, Real, C3 > out, unsigned int planner_flags=FFTW_ESTIMATE)
| Init a plan to convolve a real array with a real kernel.
template<class C1 , class C2 , class C3 >
void | init (MultiArrayView< N, Real, C1 > in, MultiArrayView< N, FFTWComplex< Real >, C2 > kernel, MultiArrayView< N, Real, C3 > out, unsigned int planner_flags=FFTW_ESTIMATE)
| Init a plan to convolve a real array with a complex kernel.
template<class C1 , class C2 , class C3 >
void | init (MultiArrayView< N, FFTWComplex< Real >, C1 > in, MultiArrayView< N, FFTWComplex< Real >, C2 > kernel, MultiArrayView< N, FFTWComplex< Real >, C3 > out, bool fourierDomainKernel, unsigned int planner_flags=FFTW_ESTIMATE)
| Init a plan to convolve a complex array with a complex kernel.
template<class C1 , class KernelIterator , class OutIterator >
void | initMany (MultiArrayView< N, Real, C1 > in, KernelIterator kernels, KernelIterator kernelsEnd, OutIterator outs, unsigned int planner_flags=FFTW_ESTIMATE)
| Init a plan to convolve a real array with a sequence of kernels.
template<class C1 , class KernelIterator , class OutIterator >
void | initMany (MultiArrayView< N, FFTWComplex< Real >, C1 > in, KernelIterator kernels, KernelIterator kernelsEnd, OutIterator outs, bool fourierDomainKernels, unsigned int planner_flags=FFTW_ESTIMATE)
| Init a plan to convolve a complex array with a sequence of kernels.

## Detailed Description

### template<unsigned int N, class Real>
class vigra::FFTWConvolvePlan< N, Real >

C++ wrapper for a pair of FFTW plans used to perform FFT-based convolution.

The class encapsulates the calls to `fftw_plan_dft_2d`, `fftw_execute`, and `fftw_destroy_plan` (and their `float` and `long double` counterparts) in an easy-to-use interface. It always creates a pair of plans, one for the forward and one for the inverse transform required for convolution.

Usually, you use this class only indirectly via convolveFFT() and its variants. You only need this class if you want to have more control about FFTW's planning process (by providing non-default planning flags) and/or want to re-use plans for several convolutions.

Usage:

#include <vigra/multi_fft.hxx>
Namespace: vigra

        // convolve a real array with a real kernel
        MultiArray<2, double> src(Shape2(w, h)), dest(Shape2(w, h));

        MultiArray<2, double> spatial_kernel(Shape2(9, 9));
        Gaussian<double> gauss(1.0);

        for(int y=0; y<9; ++y)
            for(int x=0; x<9; ++x)
                spatial_kernel(x, y) = gauss(x-4.0)*gauss(y-4.0);

        // create an optimized plan by measuring the speed of several algorithm variants
        FFTWConvolvePlan<2, double> plan(src, spatial_kernel, dest, FFTW_MEASURE);

        plan.execute(src, spatial_kernel, dest);

## Constructor & Destructor Documentation

FFTWConvolvePlan | ( |  | ) |

Create an empty plan.

The plan can be initialized later by one of the init() functions.

FFTWConvolvePlan | ( | MultiArrayView< N, Real, C1 > | in,
|  | MultiArrayView< N, Real, C2 > | kernel,
|  | MultiArrayView< N, Real, C3 > | out,
|  | unsigned int | planner_flags = `FFTW_ESTIMATE`
| ) |  |

Create a plan to convolve a real array with a real kernel.

The kernel must be defined in the spatial domain. See convolveFFT() for detailed information on required shapes and internal padding.

- planner_flags must be a combination of the planner flags defined by the FFTW library. The default `FFTW_ESTIMATE` will guess optimal algorithm settings or read them from pre-loaded "wisdom".

FFTWConvolvePlan | ( | MultiArrayView< N, Real, C1 > | in,
|  | MultiArrayView< N, FFTWComplex< Real >, C2 > | kernel,
|  | MultiArrayView< N, Real, C3 > | out,
|  | unsigned int | planner_flags = `FFTW_ESTIMATE`
| ) |  |

Create a plan to convolve a real array with a complex kernel.

The kernel must be defined in the Fourier domain, using the half-space format. See convolveFFT() for detailed information on required shapes and internal padding.

- planner_flags must be a combination of the planner flags defined by the FFTW library. The default `FFTW_ESTIMATE` will guess optimal algorithm settings or read them from pre-loaded "wisdom".

FFTWConvolvePlan | ( | MultiArrayView< N, FFTWComplex< Real >, C1 > | in,
|  | MultiArrayView< N, FFTWComplex< Real >, C2 > | kernel,
|  | MultiArrayView< N, FFTWComplex< Real >, C3 > | out,
|  | bool | fourierDomainKernel,
|  | unsigned int | planner_flags = `FFTW_ESTIMATE`
| ) |  |

Create a plan to convolve a complex array with a complex kernel.

See convolveFFT() for detailed information on required shapes and internal padding.

- fourierDomainKernel determines if the kernel is defined in the spatial or Fourier domain.
- planner_flags must be a combination of the planner flags defined by the FFTW library. The default `FFTW_ESTIMATE` will guess optimal algorithm settings or read them from pre-loaded "wisdom".

FFTWConvolvePlan | ( | Shape | inOut,
|  | Shape | kernel,
|  | bool | useFourierKernel = `false`,
|  | unsigned int | planner_flags = `FFTW_ESTIMATE`
| ) |  |

Create a plan from just the shape information.

See convolveFFT() for detailed information on required shapes and internal padding.

- fourierDomainKernel determines if the kernel is defined in the spatial or Fourier domain.
- planner_flags must be a combination of the planner flags defined by the FFTW library. The default `FFTW_ESTIMATE` will guess optimal algorithm settings or read them from pre-loaded "wisdom".

## Member Function Documentation

void init | ( | MultiArrayView< N, Real, C1 > | in,
|  | MultiArrayView< N, Real, C2 > | kernel,
|  | MultiArrayView< N, Real, C3 > | out,
|  | unsigned int | planner_flags = `FFTW_ESTIMATE`
| ) |  |

Init a plan to convolve a real array with a real kernel.

See the constructor with the same signature for details.

void init | ( | MultiArrayView< N, Real, C1 > | in,
|  | MultiArrayView< N, FFTWComplex< Real >, C2 > | kernel,
|  | MultiArrayView< N, Real, C3 > | out,
|  | unsigned int | planner_flags = `FFTW_ESTIMATE`
| ) |  |

Init a plan to convolve a real array with a complex kernel.

See the constructor with the same signature for details.

void init | ( | MultiArrayView< N, FFTWComplex< Real >, C1 > | in,
|  | MultiArrayView< N, FFTWComplex< Real >, C2 > | kernel,
|  | MultiArrayView< N, FFTWComplex< Real >, C3 > | out,
|  | bool | fourierDomainKernel,
|  | unsigned int | planner_flags = `FFTW_ESTIMATE`
| ) |  |

Init a plan to convolve a complex array with a complex kernel.

See the constructor with the same signature for details.

void initMany | ( | MultiArrayView< N, Real, C1 > | in,
|  | KernelIterator | kernels,
|  | KernelIterator | kernelsEnd,
|  | OutIterator | outs,
|  | unsigned int | planner_flags = `FFTW_ESTIMATE`
| ) |  |

Init a plan to convolve a real array with a sequence of kernels.

The kernels can be either real or complex. The sequences kernels and outs must have the same length. See the corresponding constructors for single kernels for details.

void initMany | ( | MultiArrayView< N, FFTWComplex< Real >, C1 > | in,
|  | KernelIterator | kernels,
|  | KernelIterator | kernelsEnd,
|  | OutIterator | outs,
|  | bool | fourierDomainKernels,
|  | unsigned int | planner_flags = `FFTW_ESTIMATE`
| ) |  |

Init a plan to convolve a complex array with a sequence of kernels.

The kernels must be complex as well. The sequences kernels and outs must have the same length. See the corresponding constructors for single kernels for details.

void execute | ( | MultiArrayView< N, Real, C1 > | in,
|  | MultiArrayView< N, Real, C2 > | kernel,
|  | MultiArrayView< N, Real, C3 > | out
| ) |  |

Execute a plan to convolve a real array with a real kernel.

The array shapes must be the same as in the corresponding init function or constructor. However, execute() can be called several times on the same plan, even with different arrays, as long as they have the appropriate shapes.

void execute | ( | MultiArrayView< N, Real, C1 > | in,
|  | MultiArrayView< N, FFTWComplex< Real >, C2 > | kernel,
|  | MultiArrayView< N, Real, C3 > | out
| ) |  |

Execute a plan to convolve a real array with a complex kernel.

The array shapes must be the same as in the corresponding init function or constructor. However, execute() can be called several times on the same plan, even with different arrays, as long as they have the appropriate shapes.

void execute | ( | MultiArrayView< N, FFTWComplex< Real >, C1 > | in,
|  | MultiArrayView< N, FFTWComplex< Real >, C2 > | kernel,
|  | MultiArrayView< N, FFTWComplex< Real >, C3 > | out
| ) |  |

Execute a plan to convolve a complex array with a complex kernel.

The array shapes must be the same as in the corresponding init function or constructor. However, execute() can be called several times on the same plan, even with different arrays, as long as they have the appropriate shapes.

void executeMany | ( | MultiArrayView< N, FFTWComplex< Real >, C1 > | in,
|  | KernelIterator | kernels,
|  | KernelIterator | kernelsEnd,
|  | OutIterator | outs
| ) |  |

Execute a plan to convolve a complex array with a sequence of kernels.

The array shapes must be the same as in the corresponding init function or constructor. However, executeMany() can be called several times on the same plan, even with different arrays, as long as they have the appropriate shapes.

void executeMany | ( | MultiArrayView< N, Real, C1 > | in,
|  | KernelIterator | kernels,
|  | KernelIterator | kernelsEnd,
|  | OutIterator | outs
| ) |  |

Execute a plan to convolve a real array with a sequence of kernels.

The array shapes must be the same as in the corresponding init function or constructor. However, executeMany() can be called several times on the same plan, even with different arrays, as long as they have the appropriate shapes.

The documentation for this class was generated from the following file:

- vigra/multi_fft.hxx

© Ullrich Köthe (ullrich.koethe@iwr.uni-heidelberg.de) Heidelberg Collaboratory for Image Processing, University of Heidelberg, Germany | html generated using doxygen and Python vigra 1.9.0 (Tue Nov 6 2012)