This notebook sketches how to integrate the convolution operation into the astropy compound model framework

astropy_models_convolution.ipynb

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    "# Proof of concept: compound models and convolution\n",
    "\n",
    "This notebook sketches how to integrate the convolution operation into the astropy compound model framework"
   ]
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   "source": [
    "import numpy as np\n",
    "from astropy.modeling.models import Gaussian1D\n",
    "from astropy.modeling.core import _make_arithmetic_operator, BINARY_OPERATORS, _CompoundModelMeta\n",
    "from scipy.signal import fftconvolve\n",
    "from functools import partial"
   ]
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    "# define source model\n",
    "source = Gaussian1D(1, 0, 1, name='Source')\n",
    "\n",
    "# PSF is not normalized, but OK for a quick test\n",
    "psf = Gaussian1D(1, 0, 1, name='PSF')"
   ]
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    "# wrap fftconvolve to pass arguments, any other mode than 'same' won't work\n",
    "# for compound models (because the they expect the same shape for input and output arrays)\n",
    "convolve_func = partial(fftconvolve, mode='same')\n",
    "\n",
    "# add convolution to the binary operators\n",
    "BINARY_OPERATORS['convolve'] = _make_arithmetic_operator(convolve_func)\n",
    "\n",
    "# create compound model from two models and convolution operator\n",
    "conv = _CompoundModelMeta._from_operator('convolve', source, psf)"
   ]
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      "text/plain": [
       "array([ 0.00342127,  0.03246698,  0.18679594,  0.65211678,  1.38024565,\n",
       "        1.7726372 ,  1.38024565,  0.65211678,  0.18679594,  0.03246698,\n",
       "        0.00342127])"
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     "execution_count": 8,
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   "source": [
    "# evaluate\n",
    "x = np.arange(-5, 6)\n",
    "conv(x)"
   ]
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   "execution_count": 9,
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      "text/plain": [
       "array([ 0.00342127,  0.03246698,  0.18679594,  0.65211678,  1.38024565,\n",
       "        1.7726372 ,  1.38024565,  0.65211678,  0.18679594,  0.03246698,\n",
       "        0.00342127])"
      ]
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     "execution_count": 9,
     "metadata": {},
     "output_type": "execute_result"
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   ],
   "source": [
    "# check the result\n",
    "fftconvolve(source(x), psf(x), 'same')"
   ]
  },
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