eos.py 文件源码

def E_MurnV(V,a0,a1,a2,a3):
    """
    This function implements the Murnaghan EOS (in a form which is best for fitting).
    Returns the energy at the volume *V* using the coefficients *a0,a1,a2,a3* 
    from the equation:

    .. math::
       E = a_0 - (a_2*a_1)/(a_3-1.0) V a_2/a_3 ( a_1/V^{a_3})/(a_3-1.0) +1.0 )

    """
    res=np.zeros(len(V))
    for i in range(0,len(V)):
        res[i]=a0 - a2*a1/(a3-1.0) + V[i]*a2/a3*( pow(a1/V[i],a3)/(a3-1.0)+1.0 )
    return res

# Other functions