Module: Tools

Helpers for post-processing simulation data: slices through 1D/2D/3D arrays, centre of mass, particle number, condensation and flow energies.

Module: tools

List of functions

libnest.tools.threeSlice(variable)

Returns 1, 2 or 3 dimensional numpy array with slices through given variable.

It works for 1D, 2D, 3D.

By default it cuts through the center.

Parameters:

variable (numpy.ndarray) – 1D, 2D or 3D array

Returns:

slices through the centre along each axis

Return type:

numpy.ndarray

libnest.tools.centerOfMass(density)

Returns numpy array of center of masses coordinates.

It works for 1D, 2D, 3D.

Note

The center of mass unit here is unitless (units of grid)

Parameters:

density (numpy.ndarray) – \(\rho_n\) [fm ^-3] at subsequent time steps, shape (nt, nx, ny, nz)

Returns:

2 dimensional numpy array of center of mass coordinates at subsequent time steps [[x0,y0,z0], [x1,y1,z1],…]

libnest.tools.condensationEnergy(density, delta, dV=1.0)

Calculates the condensation energy by calculating proper function of system density \(\rho\), and pairing field \(\Delta\). The Fermi energy \(\epsilon^*_{F}\) is calculated under the assumption that the effective mass is taken into account. It works for 1D, 2D, 3D. Returns numpy array of values of condensation energy. 1 dimensional numpy array of condensation energy

\[E_{\mathrm{cond}} = \int_V \frac{3}{8} \frac{|\Delta(\bm r)|^2}{\epsilon^*_{F}(\bm r)}\rho(\bm r)d{\bm r}\]

Parameters:

• density (float) – \(\rho\) [fm ^-3]

• delta (float) – \(\Delta\) [MeV]

• dV (float) – infinitesimal element of volume (by default set to 1.0)

Returns:

condensation energy \(E_{\mathrm{cond}}\) at subsequent time steps [e0, e1,…]

Return type:

float

libnest.tools.flowEnergy(j, density_n, density_p)

Returns numpy array of values of flow energy.

It works for 1D, 2D, 3D.

Formula: integral hbar*c*j^2/(2mc^2 density) dr

Parameters:

• j (numpy.ndarray) – current, shape (nt, 3, nx, ny, nz)

• density_n (numpy.ndarray) – neutron density [fm ^-3], shape (nt, nx, ny, nz)

• density_p (numpy.ndarray) – proton density [fm ^-3], shape (nt, nx, ny, nz)

Returns:

1 dimensional numpy array of flow energy at subsequent time steps [e0, e1,…]

libnest.tools.particleN(density)

Returns number of particles.

It works for 1D, 2D, 3D. For static nucleus it is constant, however there are some system scenarios where the number of particles might change.

Parameters:

density (numpy.ndarray) – density [fm ^-3], shape (nt, nx, ny, nz)

Returns:

1 dimensional numpy array of number of particles at subsequent time steps [N0, N1,…]