[Wien] Error in Volume Optimization for TiC

[Stefaan Cottenier]

> I done volume optimization after scf calculation for TiC. I cannot found
> optimized lattice parameter.

How many E(V) data points did you put into case.vol? According to your 
output, you gave only a single point:

>           vol       energy         de(Birch-Murnaghan)  Pressure(GPa)
>       139.5080    -1783.963311  1783.963311                0.000
>                    Sigma:       1783.963311


Of course, a 4-parameter equation cannot be fit through a single data point.

Stefaan