Dear NWChem developers and users,
We are currently having troubles with the CPHF Module during the frequency analysis.
The Iterative solution of linear equations are not converging, which results in the error message "ikain not converged".
We managed to set the number of iterations higher with "set cphf:maxiter 2500", but they are simply continuing without converging. This happens for a range of structures/isomers. How can we modify the input to help the convergence?
This is our input (without the "set cphf:maxiter 2500"):
start Sn10P2_1SiPBE0
memory total 32000 mb
charge 0
geometry units angstrom noautoz noautosym
Sn 0.26925119 1.31076216 1.34259267
Sn 1.57791812 -0.72646357 -0.78694794
Sn -0.31621535 -1.76669855 1.51215804
Sn -2.60153299 -1.06867122 -0.61711425
Sn -2.09472757 1.92404765 -0.88224526
Sn -0.92864827 0.03956535 -2.89486175
Sn -2.39715028 0.52585329 1.90018541
Sn -0.32598565 -2.74446405 -1.43359287
Sn 2.63361744 -0.31579865 2.21931902
Sn 2.87506804 2.35376327 0.01632841
P 3.89433998 -0.01255075 0.01213677
P 0.58277208 1.63770465 -1.28199310
end
basis
* library def2-tzvpp
end
ecp
Sn library def2-ecp
end
dft
vectors input test.movecs output dft.movecs
xc pbe0
direct grid xfine
mult 1
convergence ncydp 0 dampon 1d99 dampoff 1d-7 damp 70
iterations 750
noio
end
task dft freq
Which results in the following (partial) output:
NWChem CPHF Module
------------------
scftype = RHF
nclosed = 125
nopen = 0
variables = 70125
# of vectors = 36
tolerance = 0.10D-03
level shift = 0.00D+00
max iterations = 50
max subspace = 360
Grid integrated density: 249.999995405115
Requested integration accuracy: 0.10E-13
SCF residual: 1.406252467695138E-004
Iterative solution of linear equations
No. of variables 70125
No. of equations 36
Maximum subspace 360
Iterations 50
Convergence 1.0D-04
Start time 11581.9
iter nsub residual time
---- ------ -------- ---------
1 36 7.89D-02 13507.1
2 72 4.62D-02 15430.3
3 108 1.35D-02 17354.8
4 144 1.78D-02 19278.3
5 180 9.51D-03 21202.9
6 216 2.64D-03 23127.5
7 252 2.01D-03 25052.1
8 288 1.81D-03 26976.3
9 324 2.33D-03 28900.8
10 360 1.20D-03 30825.6
11 360 1.16D-03 32750.1
12 360 1.32D-03 34674.6
13 360 1.95D-03 36598.9
14 360 2.83D-03 38523.6
15 360 9.89D-03 40449.2
16 360 1.21D-02 42374.0
17 360 7.45D-03 44298.7
18 360 5.96D-03 46223.9
19 360 6.84D-03 48148.9
20 360 4.36D-03 50074.1
21 360 4.84D-03 51999.1
22 360 5.85D-03 53924.5
23 360 2.57D-03 55849.6
24 360 3.52D-03 57775.6
25 360 3.40D-03 59700.1
26 360 7.79D-03 61624.8
27 360 1.20D-02 63549.0
28 360 6.15D-03 65473.2
29 360 6.80D-03 67398.7
30 360 4.00D-03 69323.5
31 360 4.38D-03 71248.2
32 360 5.43D-03 73173.4
33 360 8.65D-03 75099.5
34 360 3.89D-03 77024.0
35 360 2.65D-03 78949.3
36 360 3.01D-03 80873.5
37 360 6.64D-03 82797.5
38 360 5.16D-03 84722.5
39 360 4.49D-03 86647.1
40 360 4.64D-03 88572.1
41 360 3.54D-03 90497.1
42 360 2.21D-03 92421.8
43 360 4.54D-03 94347.5
44 360 3.59D-03 96272.7
45 360 6.50D-03 98198.2
46 360 4.00D-03 100122.7
47 360 4.88D-03 102047.4
48 360 5.20D-03 103972.0
49 360 3.35D-03 105898.4
50 360 3.00D-03 107824.8
------------------------------------------------------------------------
lkain: not converged 0
lkain: not converged 0
lkain: not converged 0
lkain: not converged 0
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lkain: not converged 0
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lkain: not converged 0
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lkain: not converged 0
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current input line :
current input line :
current input line :
current input line :
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This type of error is most commonly associated with calculations not reaching
convergence criteria
lkain: not converged 0
This type of error is most commonly associated with calculations not reaching
convergence criteria
Thank you in advance!
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