Error in estimating error of (a**x)

[Codeprey]

Hello, I am trying to estimate the error of a formula, and the code goes to a dead loop. After some attempts I find the problem lies in the (a**x) like formula, which belongs to 'rpow' type.

A simple example for a dead loop is like:

alpha=N(20,1) 10**alpha Traceback (most recent call last): File "", line 1, in File "/opt/anaconda3/lib/python3.7/site-packages/soerp/init.py", line 426, in rpow return _make_UF_compatible_object(ADF.rpow(self, val)) File "/opt/anaconda3/lib/python3.7/site-packages/ad/init.py", line 787, in rpow return to_auto_diff(val)**self File "/opt/anaconda3/lib/python3.7/site-packages/soerp/init.py", line 426, in rpow return _make_UF_compatible_object(ADF.rpow(self, val)) File "/opt/anaconda3/lib/python3.7/site-packages/ad/init.py", line 787, in rpow return to_auto_diff(val)**self File "/opt/anaconda3/lib/python3.7/site-packages/soerp/init.py", line 426, in rpow return _make_UF_compatible_object(ADF.rpow(self, val)) File "/opt/anaconda3/lib/python3.7/site-packages/ad/init.py", line 787, in rpow return to_auto_diff(val)**self (984 loops skipped...) File "/opt/anaconda3/lib/python3.7/site-packages/soerp/init.py", line 426, in rpow return _make_UF_compatible_object(ADF.rpow(self, val)) File "/opt/anaconda3/lib/python3.7/site-packages/ad/init.py", line 787, in rpow return to_auto_diff(val)**self File "/opt/anaconda3/lib/python3.7/site-packages/soerp/init.py", line 426, in rpow return _make_UF_compatible_object(ADF.rpow(self, val)) File "/opt/anaconda3/lib/python3.7/site-packages/ad/init.py", line 787, in rpow return to_auto_diff(val)**self File "/opt/anaconda3/lib/python3.7/site-packages/soerp/init.py", line 426, in rpow return _make_UF_compatible_object(ADF.rpow(self, val)) File "/opt/anaconda3/lib/python3.7/site-packages/ad/init.py", line 787, in rpow return to_auto_diff(val)**self File "/opt/anaconda3/lib/python3.7/site-packages/soerp/init.py", line 426, in rpow return _make_UF_compatible_object(ADF.rpow(self, val)) File "/opt/anaconda3/lib/python3.7/site-packages/ad/init.py", line 787, in rpow return to_auto_diff(val)**self File "/opt/anaconda3/lib/python3.7/site-packages/ad/init.py", line 39, in to_auto_diff if isinstance(x, ADF): RecursionError: maximum recursion depth exceeded while calling a Python object

In soerp/init.py: def rpow(self, val): return _make_UF_compatible_object(ADF.rpow(self, val))

In ad/init.py: def rpow(self,val): return to_auto_diff(val)**self

Please solve this problem, thanks!

Sincerely, Peter