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专业: 凝聚态物性 II ：电子结构

[求助] 掺杂后的结构计算弹性常数出现问题（急），请大家一定要帮帮忙啊~~

我有两个问题，想问一下大家，
1.我在计算弹性常数的时候计算出来的cij-1-2.castep这种文件中都是收敛的，但老是出现这样的提醒，这是怎么回事。
*** There were at least 4 warnings during this run ***
*** => please check the whole of this file carefully! ***

2.如果cij-1-2.castep这类文件中不收敛，是怎么回事，是不是要重新计算。

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1楼2012-12-14 19:11:45

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专业: 凝聚态物性 II ：电子结构

BFGS: Warning - trial step suggests complex energy landscape
               in which simple line minimization will fail.

            - This is usually an indication that the forces/streses
               are not accurate enough. Consider making the following changes:

               1) Increase cutoff_energy or basis_precision
               2) Reduce elec_energy_tol and/or elec_force_tol
               3) Increase grid_scale
               4) Increase fine_grid_scale

            - Proceeding with a bisection search to find root instead.

BFGS: Warning - Repeated consecutive reset of inverse Hessian
BFGS:          without satisfying convergence criteria which
BFGS:          looks like BFGS has run out of search directions.
BFGS: Warning - Lets try allowing some uphill steps and see if
BFGS:          we can get around this barrier.
BFGS: Warning - It is possible that the system may now converge to
BFGS:          a stationary point OTHER than the desired minimum.
BFGS: Hint - this may be an indication that either:
BFGS:          a) you are using a poor guess at geom_frequency_est
BFGS:          and/or geom_modulus_est, or
BFGS:          b) you are using unrealistic convergence criteria.
BFGS:          Suggest therefore that you consider changing them!

总是出现这样的警告，这是什么意思，怎么解决