<SYSTEM_TASK:>
Given the following text description, write Python code to implement the functionality described below step by step
<END_TASK>
<USER_TASK:>
Description:
 Critical Radii
Step1:  As always, let's do imports and initialize a logger and a new Bundle.  See Building a System for more details.
Step2:  Detached Systems
Detached systems are the default case for default_binary.  The requiv_max parameter is constrained to show the maximum value for requiv before the system will begin overflowing at periastron.
Step3:  We can see that the default system is well within this critical value by printing all radii and critical radii.
Step4:  If we increase 'requiv' past the critical point, we'll receive a warning from the logger and would get an error if attempting to call b.run_compute().
<ASSISTANT_TASK:>
Python Code:
!pip install -I "phoebe>=2.2,<2.3"
Explanation: Critical Radii: Detached Systems
Setup
Let's first make sure we have the latest version of PHOEBE 2.2 installed. (You can comment out this line if you don't use pip for your installation or don't want to update to the latest release).
End of explanation
%matplotlib inline
import phoebe
from phoebe import u # units
import numpy as np
import matplotlib.pyplot as plt
logger = phoebe.logger()
b = phoebe.default_binary()
Explanation: As always, let's do imports and initialize a logger and a new Bundle.  See Building a System for more details.
End of explanation
b['requiv_max@component@primary']
b['requiv_max@constraint@primary']
Explanation: Detached Systems
Detached systems are the default case for default_binary.  The requiv_max parameter is constrained to show the maximum value for requiv before the system will begin overflowing at periastron.
End of explanation
print(b.filter(qualifier='requiv*', context='component'))
Explanation: We can see that the default system is well within this critical value by printing all radii and critical radii.
End of explanation
b['requiv@primary'] = 2.2
print(b.run_checks())
Explanation: If we increase 'requiv' past the critical point, we'll receive a warning from the logger and would get an error if attempting to call b.run_compute().
End of explanation
<END_TASK>