Is there a constant defined in SageMath that I can use to distinguish whether Sage is running or pure Python? Something that I can use like this:
SAGE = False
try:
SAGE = ZZ
except NameError:
pass
print(SAGE)Contrary to my expectations, the Sage Cell Server outputs 'Integer Ring' in both cases.
It depends on what you mean by "Sage is running". If you mean, "have the standard Sage commands, etc., been imported and are ready for use," then you could test
import sys
if 'sage' in sys.modules:
print('The Sage library has been imported')This seems to be the case with the Sage Cell server for both Sage and Python: Sage has been imported in both cases. That's why your test isn't distinguishing the two. Along the same lines, print(sage.version.version) returns 10.2 in both Sage and Python on the Sage Cell server.
If you mean, "is Sage's preparser running," then the answer from @PedroBrazil is correct. In Python, ^ means bitwise exclusive or, while by default in Sage, ^ is exponentiation. The preparser can be turned off while still running Sage, though, so this is not a perfect test.
My guess is that the "Python" setting for the Sage Cell Server imports all of Sage and just turns off the preparser. So again, it depends on what you need to test, why you need to know whether it's Sage or Python.
This 1-liner fulfills the purpose (tested with the Sage Cell Server).
def is_sage_running(): return 2^3 != 1
print(is_sage_running())Sage Math Server's behavior is clearly misleading the user and should be changed immediately.
def issage():
try:
import sage.all
return True
except ImportError:
return False
print(issage())This should work independent of the preparser.
This tests whether Sage can be imported, not whether it already has been, and furthermore it imports it if it can be: it has side effects.
That's right. Then it's not really any good.
Asked: 0 years ago
Seen: 168 times
Last updated: Jan 29
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