profitMakeConvolver: Creates a Convolver object.

In ProFit: Fit Projected 2D Profiles to Galaxy Images

Description

Creates a Convolver object that can be used to perform convolution of images. Convolution can be carried out direcly via profitConvolve or when creating Model images with profitMakeModel.

This function allows users to create specific convolvers instead of letting profitMakeModel create a default one.

Usage

profitMakeConvolver(type, image_dimensions, psf,
 reuse_psf_fft = TRUE, fft_effort = 0, omp_threads = NULL, openclenv = NULL)

Arguments

type	The type of convolver to create. It should be one of the strings returned by profitAvailableConvolvers
image_dimensions	Dimensions of the images that will be convolved by this convolver.
psf	The point spread function (PSF) image matrix that will be used by this Convolver.
reuse_psf_fft	Logical; whether the FFT-ed version of the PSF used by the Convolver should be re-used across executions of the convolution. This is useful if the convolver will be re-used to convolve different images (of the same size) with the same PSF. Used only if type is "fft" and ProFit has FFTW support.
fft_effort	Amount of effort to spend creating the FFTW plans used by this Convolver. Accepted values range from 0 to 3, and map to the ESTIMATE, MEASURE, PATIENT and EXHAUSTIVE FFTW efforts, respectively. Used only if type is "fft" and ProFit has FFTW support.
omp_threads	Specifies the number of OpenMP threads to use to execute the underlying FFTW plans. Used only if type is "fft" and ProFit has FFTW support, OpenMP support, and the underlying FFTW library has OpenMP support.
openclenv	A valid pointer to an OpenCL environment (obtained from the profitOpenCLEnv). Used only if type is "opencl" or "opencl-local" and ProFit has OpenCL support.

Details

A convolver object can be used to perform one or more image convolutions. Depending on the convolver's requested configuration, it could be expensive to create them. Users should thus try to keep a hold on these objects.

Value

The output is an external pointer of class 'externalptr' to be passed to profitMakeModel via its convopt list option, or to be used to convolve images directly via profitConvolve

Author(s)

Rodrigo Tobar

See Also

profitAvailableConvolvers, profitConvolve, profitBruteConv, profitMakePointSource, profitBenchmarkConv, profitHasFFTW profitOpenCLEnv

Examples

## Not run: 
psf = profitMakeGaussianPSF(dim=c(100,100))

has_openCL=profitHasOpenCL()
has_fft = profitHasFFTW()
has_openMP=profitHasOpenMP()

convolver_brute = profitMakeConvolver("brute", c(400, 400), psf)

if(has_openCL){
  convolver_bruteCL = profitMakeConvolver("opencl", c(400, 400), psf,
  openclenv=profitOpenCLEnv())
}

if(has_fft){
	convolver_fft = profitMakeConvolver("fft", c(400, 400), psf, fft_effort=1,
	omp_threads=1)
}

if(has_fft & has_openMP){
	convolver_fftMP = profitMakeConvolver("fft", c(400, 400), psf, fft_effort=1,
	omp_threads=4)
}

model = list(
  sersic = list(
    xcen   = c(80, 210),
    ycen   = c(190, 50),
    mag = c(15, 13),
    re  = c(14, 5),
    nser  = c(3, 10),
    ang  = c(46, 80),
    axrat  = c(0.4, 0.6),
    box = c(0.5,-0.5)
  )
)

system.time(for(i in 1:10){image_brute=profitMakeModel(model=model, dim=c(300,300), psf=psf,
  convopt=list(convolver=convolver_brute))$z})

if(has_openCL){
system.time(for(i in 1:10){image_bruteCL=profitMakeModel(model=model, dim=c(300,300), psf=psf,
  convopt=list(convolver=convolver_bruteCL))$z})
}

if(has_fft){
system.time(for(i in 1:10){image_fft=profitMakeModel(model=model, dim=c(300,300), psf=psf,
  convopt=list(convolver=convolver_fft))$z})
}

if(has_fft & has_openMP){
system.time(for(i in 1:10){image_fftMP=profitMakeModel(model=model, dim=c(300,300), psf=psf,
  convopt=list(convolver=convolver_fftMP))$z})
}

magimage(image_brute)

if(has_openCL){
  magimage(image_bruteCL)
  magimage(image_brute-image_bruteCL)
}

if(has_fft){
  magimage(image_fft)
  magimage(image_brute-image_fft)
}

if(has_fft & has_openMP){
  magimage(image_fftMP)
  magimage(image_brute-image_fftMP)
}

## End(Not run)

ProFit documentation built on Nov. 11, 2019, 5:07 p.m.