geometry optimization runs out of cycles

job314

I noticed that MAXCYCLE keyword does not work very well in optimization. I had the same problem with EOS - it runs out of arbitrary number of cycles nevermind I specify MAXCYCLE as a large number.

Simple geometry optimization of a large cell, restarted, with MAXCYCLE 700 stops after 200 cycles - I am sure logical reason for it exists, perhaps you can advise?

PREDICTED ENERGY CHANGE -0.366E-07

MAX GRADIENT 0.000036 THRESHOLD 0.000045 CONVERGED YES
RMS GRADIENT 0.000005 THRESHOLD 0.000030 CONVERGED YES
MAX DISPLAC. 0.000921 THRESHOLD 0.000180 CONVERGED NO
RMS DISPLAC. 0.000167 THRESHOLD 0.000120 CONVERGED NO
CONVERGENCE TESTS UNSATISFIED AFTER 200 ENERGY AND GRADIENT CALCULATIONS

OPT END - FAILED * E(AU): -2.756455928711E+04 POINTS 200 *

INPUT (2).d12 Input and output.out output

aerba

Hi,

I have looked at the code and figured out what is going on. Let me explain what is happening first. I'll then offer a solution below.

You are running a pre-optimization within a frequency calculation + Raman intensity calculation (via the CPHF/KS approach):

FREQCALC
FRAGMENT
19
9 106 131 175 191 192 193  194 195 196 197 198 199 200 201 202 203 204 205
PREOPTGEOM
RESTART
MAXCYCLE
700
ATOMONLY
END
INTENS
INTRAMAN
INTCPHF
END
END

It turns out that the same variable is used in the code to define the maximum number of optimization steps and the maximum number of cycles in the CPHF/KS process. The default maximum number of cycles for CPHF/KS for intensity calculations is 200. Thus what happens is that with MAXCYCLE you set it to 700 but when the INTCPHF keyword is read it is internally re-set to the default of 200.

Clearly, this is not ideal! We are going to fix it in future versions.

Luckily, there is a simple workaround. Everything is fine if you run a geometry optimization first, then followed by a subsequent frequency calculation starting from the optimized geometry.

The first calculation would look something like:

OPTGEOM
ATOMONLY
MAXCYCLE
700
END

And the second one (from the optimized geometry obtained at the previous step) would be:

FREQCALC
FRAGMENT
19
9 106 131 175 191 192 193  194 195 196 197 198 199 200 201 202 203 204 205
INTENS
INTRAMAN
INTCPHF
END
END

Hope this helps

job314

thank you