qmctorch.wavefunction.jastrows.distance.electron_electron_distance module

class qmctorch.wavefunction.jastrows.distance.electron_electron_distance.ElectronElectronDistance(nelec, ndim=3, scale=False, scale_factor=0.6)

Bases: sphinx.ext.autodoc.importer._MockObject

Computes the electron-electron distances

\[r_{ij} = \sqrt{ (x_i-x_j)^2 + (y_i-y_j)^2 + (z_i-z_j)^2}\]

Parameters:

• nelec (int) – number of electrons
• ndim (int) – number of spatial dimensions
• scale (bool, optional) – return scaled values, Defaults to False
• scale_factor (float, optional) – value of the scale factor, Defaults to 0.6

Examples::

>>> edist = ElectronDistance(2,3)
>>> pos = torch.tensor(500,6)
>>> r = edist(pos)
>>> dr = edist(pos,derivative=1)

forward(input, derivative=0)

Compute the pairwise distance between the electrons or its derivative.

When required, the derivative is computed wrt to the first electron i.e.

\[\frac{dr_{ij}}{dx_i}\]

which is different from :

\[\frac{d r_{ij}}{dx_j} = -\frac{dr_{ij}}{dx_i}\]

Parameters:

• input (torch.tesnor) –

  position of the electron

  size : Nbatch x [Nelec x Ndim]

• derivative (int, optional) –

  degre of the derivative.

  Defaults to 0.

Returns:

distance (or derivative) matrix

Nbatch x Nelec x Nelec if derivative = 0

Nbatch x Ndim x Nelec x Nelec if derivative = 1,2

Return type:

torch.tensor

safe_sqrt(dist)

Compute the square root of the electron electron distance matrix.

Parameters:dist (torch.tensor) – ee distances squared Nbatch x Nelec x Nelec Returns:sqrt of dist Nbatch x Nelec x Nelec Return type:torch.tensor

get_der_distance(pos, dist)

Get the derivative of the electron electron distance matrix.

\[\frac{d r_{ij}}{d x_i}\]

Parameters:

• pos (torch.tensor) – positions of the electrons Nbatch x Nelec x Ndim
• dist (torch.tensor) – distance matrix between the elecs Nbatch x Nelec x Nelec

Returns:

[description]

Return type:

[type]

get_second_der_distance(pos, dist)

Get the second derivative of the electron electron distance matrix.

\[\frac{d^2 r_{ij}}{d x_i^2}\]

Parameters:

• pos (torch.tensor) – positions of the electrons Nbatch x Nelec x Ndim
• dist (torch.tensor) – distance matrix between the elecs Nbatch x Nelec x Nelec

Returns:

[description]

Return type:

[type]

static get_distance_quadratic(pos)

Compute the distance following a quadratic expansion

Parameters:{torch.tensor} -- electron position [nbatch x nelec x ndim] (pos) – Returns:torch.tensor – distance matrices nbatch x nelec x ndim]

static get_difference(pos)

Compute the difference ri - rj

Parameters:{torch.tensor} -- electron position [nbatch x nelec x ndim] (pos) – Returns:torch.tensor – distance matrices nbatch x nelec x nelec x ndim]