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Hi, and thanks as always for cdb.

How should I go about writng a propagator and taking its derivative? I tried

from cdb.sympy.calculus import *

diff($1/(\eta_{\mu\nu} x^{\mu}x^{\nu})$, $x^{\mu}$);

but that doesn't work. Any advice?

Thanks GPN

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I now tried

from cdb.sympy.calculus import *

diff($1/(\eta_{\mu\nu} x^{\mu}x^{\nu})$, $x^{\rho}$);

which gave the error message

File "/home/gpn/.config/cadabra_packages/cdb/sympy/calculus.py", line 20, in diff
    dvars.append( sbtmp.to_sympy() )
RuntimeError: Dependencies on derivatives are not yet handled in the SymPy bridge

so I conclude this is not yet possible in cdb. If anyone has a better answer please let me know.

Thanks GPN

by (2.0k points)