[Pw_forum] discrepancy in tests

[Paolo Giannozzi]

On Thu, 2015-02-26 at 22:03 +0900, ＷＡＮＧ ＹＵＡＮＱＩＮＧ wrote:

> There is one big discrepancy in lda+u_force calculation (0.3476(ref)
> vs. 0.5302).

give command "diff lda+U_force.???" and look at the force section,
towards the end. Discrepancies ike those below are acceptable:
<      atom    1 type  1   force =     0.00000033    0.00000033
0.00000033
<      atom    2 type  1   force =    -0.00000111   -0.00000111
-0.00000111
<      atom    3 type  2   force =    -0.14189745   -0.14189745
-0.14189745
<      atom    4 type  3   force =     0.14189823    0.14189823
0.14189823
---
>      atom    1 type  1   force =     0.00000040    0.00000040
0.00000040
>      atom    2 type  1   force =    -0.00000101   -0.00000101
-0.00000101
>      atom    3 type  2   force =    -0.14189797   -0.14189797
-0.14189797
>      atom    4 type  3   force =     0.14189858    0.14189858
0.14189858
848c849
<      Total force =     0.347577     Total SCF correction =
0.000020
---
>      Total force =     0.347578     Total SCF correction =
0.000021
Discrepancies larger than this are very suspicious

Paolo
-- 
Paolo Giannozzi, Dept. Chemistry&Physics&Environment, 
Univ. Udine, via delle Scienze 208, 33100 Udine, Italy
Phone +39-0432-558216, fax +39-0432-558222