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cdtools/examples/simple_ptycho_model.py
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from __future__ import division, print_function, absolute_import
import numpy as np
import torch as t
from CDTools.models import CDIModel
from CDTools import tools
__all__ = ['SimplePtycho']
class SimplePtycho(CDIModel):
"""A simple ptychography model for exploring ideas and extensions"""
def __init__(self, probe_basis, probe_guess, obj_guess,
min_translation = [0,0]):
# We have to initialize the Module
super(SimplePtycho,self).__init__()
# We first save the relevant information
self.min_translation = t.Tensor(min_translation)
self.probe_basis = t.Tensor(probe_basis)
# We rescale the probe so it learns at the same rate as the object
self.probe_norm = t.max(tools.cmath.cabs(probe_guess.to(t.float32)))
self.probe = t.nn.Parameter(probe_guess.to(t.float32)
/ self.probe_norm)
self.obj = t.nn.Parameter(obj_guess.to(t.float32))
@classmethod
def from_dataset(cls, dataset):
# First, load the information from the dataset
wavelength = dataset.wavelength
det_basis = dataset.detector_geometry['basis']
det_shape = dataset[0][1].shape
distance = dataset.detector_geometry['distance']
(indices, translations), patterns = dataset[:]
# Then, generate the probe geometry
ewg = tools.initializers.exit_wave_geometry
probe_basis, probe_shape, det_slice = ewg(det_basis,
det_shape,
wavelength,
distance,
opt_for_fft=False)
# Next generate the object geometry
pix_translations = tools.interactions.translations_to_pixel(
probe_basis, translations)
obj_size, min_translation = tools.initializers.calc_object_setup(
probe_shape, pix_translations)
# Finally, initialize the probe and object using this information
probe = tools.initializers.SHARP_style_probe(dataset,
probe_shape,
det_slice)
obj = t.ones(obj_size+(2,))
return cls(probe_basis, probe, obj, min_translation=min_translation)
def interaction(self, index, translations):
pix_trans = tools.interactions.translations_to_pixel(self.probe_basis,
translations)
pix_trans -= self.min_translation
return tools.interactions.ptycho_2D_round(self.probe_norm * self.probe,
self.obj,
pix_trans)
def forward_propagator(self, wavefields):
return tools.propagators.far_field(wavefields)
def measurement(self, wavefields):
return tools.measurements.intensity(wavefields)
def loss(self, sim_data, real_data):
return tools.losses.amplitude_mse(real_data, sim_data)
def to(self, *args, **kwargs):
super(SimplePtycho, self).to(*args, **kwargs)
self.min_translation = self.min_translation.to(*args,**kwargs)
self.probe_basis = self.probe_basis.to(*args,**kwargs)
self.probe_norm = self.probe_norm.to(*args,**kwargs)
plot_list = [
('Probe Amplitude',
lambda self, fig: tools.plotting.plot_amplitude(self.probe, fig=fig, basis=self.probe_basis)),
('Probe Phase',
lambda self, fig: tools.plotting.plot_phase(self.probe, fig=fig, basis=self.probe_basis)),
('Object Amplitude',
lambda self, fig: tools.plotting.plot_amplitude(self.obj, fig=fig, basis=self.probe_basis)),
('Object Phase',
lambda self, fig: tools.plotting.plot_phase(self.obj, fig=fig, basis=self.probe_basis))
]
def save_results(self):
probe = tools.cmath.torch_to_complex(self.probe.detach().cpu())
probe = probe * self.probe_norm.detach().cpu().numpy()
obj = tools.cmath.torch_to_complex(self.obj.detach().cpu())
return {'probe':probe,'obj':obj}
if __name__ == '__main__':