I’m having trouble getting a calculation to converge. The error I always get says the following:
** Lambda not converged to 1.0e-07 **
Fatal Error: cclambda: error
Error occurred in file: D:\a\1\s\psi4\src\psi4\cc\cclambda\cclambda.cc on line: 297
Before this happens 50 iterations of calculations get printed to the screen, and while the values in the “RMS” column remain above 1.0e-07, they do trend downward the entire time (the 50th iteration has an RMS value of 2.254e-07). I’ve read the CCLAMBDA documentation and it seems like I have the ability to enforce either a less strict limit on the convergence by modifying the value of r_convergence
or I can allow the code to perform more iterations by modifying maxiter
, in the hope that the value will drop within acceptable bounds. But despite modifying both parameters, the code’s behaviour has not changed. More specifically, I’ve added the following line of code:
psi4.set_options({'maxiter': '75', 'r_convergence': '6'})
Yet the script still only performs 50 iterations and still fails because lambda failed to converge to 7 decimal places, not 6. What is going on here? Do I need to a different function than psi4.set_options
? I’d appreciate some feedback on this issue.