Conventions for using multi-demensional arrays
Variables defined as a function of multiple variables, are stored as discrete
arrays in the form of numpy.ndarray internally. For the subscripts of such
variables, we follow the following conventions.
Conventions
Variable on a grid of volume (pressure) and tempreature
- Index-conventions
- For an array of variable \(X\) at
\(i\)-th volume/pressure
\(j\)-th tempreature
- we use
X[i, j]
- Examples
Helmholtz free energy \(F(V, T)\)
Gibbs free energy \(G(P, T)\)
Variable on a grid of volume, mode and q point
- Index-conventions
- For an array of variable \(X\) at
\(i\)-th volume
\(q\)-th \(q\)-point
\(m\)-th phonon mode
- we use
X[i, q, m]
- Examples
Mode frequency \(\omega_{qm}(V)\)
Grüneisen parameter \(\gamma_{qm}(V)\)