[BUG] Error while running example non_cartesian_reconstruction.py

[jmsweng]

System setup
OS: Windows 10, running the provided docker
Python version: 3.8.8
Python environment (if any): [e.g.] conda v4.5.11

Describe the bug
Running the code provided in the non_cartesian_reconstruction.py example results in the error
AttributeError: 'ForwardBackward' object has no attribute '_metrics'

To Reproduce
Ran code in the provided example code

Expected behavior
I'm assuming this should output something similar to figure 5 in this paper: https://arxiv.org/abs/1910.08465

Module and lines involved
Full error message:

---

AttributeError Traceback (most recent call last)
in
20 verbose=1,
21 )
---> 22 x_final, costs, metrics = reconstructor.reconstruct(
23 kspace_data=kspace_obs,
24 optimization_alg='fista',

/opt/conda/envs/pysap/lib/python3.8/site-packages/mri/reconstructors/base.py in reconstruct(self, kspace_data, optimization_alg, x_init, num_iterations, cost_op_kwargs, **kwargs)
151 **cost_op_kwargs,
152 )
--> 153 self.x_final, self.costs, *metrics = optimizer(
154 gradient_op=self.gradient_op,
155 linear_op=self.linear_op,

/opt/conda/envs/pysap/lib/python3.8/site-packages/mri/optimizers/forward_backward.py in fista(gradient_op, linear_op, prox_op, cost_op, lambda_init, max_nb_of_iter, x_init, metric_call_period, metrics, verbose, **lambda_update_params)
94
95 # Define the optimizer
---> 96 opt = ForwardBackward(
97 x=alpha_init,
98 grad=gradient_op,

/opt/conda/envs/pysap/lib/python3.8/site-packages/modopt/opt/algorithms.py in init(self, x, grad, prox, cost, beta_param, lambda_param, beta_update, lambda_update, auto_iterate, metric_call_period, metrics, linear, **kwargs)
683
684 # Set default algorithm properties
--> 685 super().init(
686 metric_call_period=metric_call_period,
687 metrics=metrics,

/opt/conda/envs/pysap/lib/python3.8/site-packages/modopt/opt/algorithms.py in init(self, metric_call_period, metrics, verbose, progress, step_size, use_gpu, **dummy_kwargs)
114 super().init(['cv_metrics'])
115
--> 116 for name, dic in self.metrics.items():
117 observer = MetricObserver(
118 name,

/opt/conda/envs/pysap/lib/python3.8/site-packages/modopt/opt/algorithms.py in metrics(self)
142 def metrics(self):
143 """Metrics."""
--> 144 return self._metrics
145
146 @metrics.setter

AttributeError: 'ForwardBackward' object has no attribute '_metrics'

Are you planning to submit a Pull Request?

• Yes
• No