[Pw_forum] new bfgs: strange behavior doing vc-relax

[Максим Попов]

Dear QE developers,

comparing vc-relax calculations between BFGS(4.2.1) and the latest BFGS(from
CVS) I faced  with a following problem:
the newest QE calculates one extra point after achieving convergence
criteria (etot_conv_thr,force_conv_thr,press_conv_thr),
which leads to slightly higher total energy.

Here are the two latest energies from outputs:
       v.4.2.1                       CVS(18.04.2011)

-242.66342170 Ry       -242.66342267 Ry
-242.66342336 Ry       -242.66284562 Ry

One can see that there is a good agreement between the last energy by
v.4.2.1 and next to the last by CVS-version, whereas
the last energy by CVS is higher by ~ 0.5 mRy.

I tried relax (cell shape fixed) also - it works fine, no extra point
calculation.

-- 
Best regards, Max Popov
Ph.D. student
Materials center Leoben (MCL), Leoben, Austria.
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