diff --git a/doc/source/reference/kwant.physics.rst b/doc/source/reference/kwant.physics.rst
index 2c457f5617e405622f42602a9f01c60a945ea555..e1c6f9019ea64b05153c1f2febf7bb4139e2a571 100644
--- a/doc/source/reference/kwant.physics.rst
+++ b/doc/source/reference/kwant.physics.rst
@@ -11,6 +11,5 @@ Leads
Bands
modes
selfenergy
- selfenergy_from_modes
PropagatingModes
StabilizedModes
diff --git a/kwant/builder.py b/kwant/builder.py
index 7487bc7503a9bd1084037f9a77cee6fd9496e74f..b6b6c66d5ff311d8c92f9acf5c35c56c19025d2d 100644
--- a/kwant/builder.py
+++ b/kwant/builder.py
@@ -479,7 +479,7 @@ class ModesLead(Lead):
"""
def __init__(self, modes_func, interface):
- self._modes_func = modes_func
+ self.modes_func = modes_func
self.interface = tuple(interface)
def finalized(self):
@@ -487,11 +487,11 @@ class ModesLead(Lead):
return self
def modes(self, energy, args=()):
- return self._modes_func(energy, args)
+ return self.modes_func(energy, args)
def selfenergy(self, energy, args=()):
- modes = self.modes(energy, args)
- return physics.selfenergy_from_modes(modes=modes)
+ propagating, stabilized = self.modes(energy, args)
+ return stabilized.selfenergy()
diff --git a/kwant/physics/leads.py b/kwant/physics/leads.py
index e77d0353028d3e4e9fac9754c76f8321472b570e..8fb6ad31a053883aa970ba4d853b9d2aed8a004a 100644
--- a/kwant/physics/leads.py
+++ b/kwant/physics/leads.py
@@ -17,8 +17,7 @@ from .. import linalg as kla
dot = np.dot
-__all__ = ['selfenergy', 'modes', 'PropagatingModes', 'StabilizedModes',
- 'selfenergy_from_modes']
+__all__ = ['selfenergy', 'modes', 'PropagatingModes', 'StabilizedModes']
# Container classes
@@ -103,6 +102,25 @@ class StabilizedModes(object):
def __getitem__(self, item):
return (self.vecs, self.vecslmbdainv, self.nmodes, self.sqrt_hop)[item]
+ def selfenergy(self):
+ """
+ Compute the self-energy generated by lead modes.
+
+ Returns
+ -------
+ Sigma : numpy array, real or complex, shape (M,M)
+ The computed self-energy. Note that even if `h_cell` and `h_hop` are
+ both real, `Sigma` will typically be complex. (More precisely, if
+ there is a propagating mode, `Sigma` will definitely be complex.)
+ """
+ v = self.sqrt_hop
+ vecs = self.vecs[:, self.nmodes:]
+ vecslmbdainv = self.vecslmbdainv[:, self.nmodes:]
+ if v is not None:
+ return dot(v, dot(vecs, la.solve(vecslmbdainv, v.T.conj())))
+ else:
+ return la.solve(vecslmbdainv.T, vecs.T).T
+
# Auxiliary functions that perform different parts of the calculation.
def setup_linsys(h_cell, h_hop, tol=1e6, stabilization=None):
@@ -534,9 +552,9 @@ def modes(h_cell, h_hop, tol=1e6, stabilization=None):
Returns
-------
PropagatingModes(wave_functions, momenta, velocities) : object
- A contained for the array of the wave functions of propagating modes,
- their momenta, and their velocities. It can be used to identify the
- gauge in which the scattering problem is solved. See
+ Contains the array of the wave functions of propagating modes, their
+ momenta, and their velocities. It can be used to identify the gauge in
+ which the scattering problem is solved. See
`~kwant.physics.PropagatingModes` for details.
StabilizedModes(vecs, vecslmbdainv, nmodes, sqrt_hop) : object
A basis of propagating and evanescent modes used by the solvers.
@@ -597,37 +615,6 @@ def modes(h_cell, h_hop, tol=1e6, stabilization=None):
return real_space_data, StabilizedModes(vecs, vecslmbdainv, nrightmovers, v)
-def selfenergy_from_modes(lead_modes):
- """
- Compute the self-energy generated by lead modes.
-
- Parameters
- ----------
- lead_modes : StabilizedModes(vecs, vecslmbdainv, nmodes, v) a named tuple
- The modes in the lead, with format defined in
- `~kwant.physics.StabilizedMods`.
-
- Returns
- -------
- Sigma : numpy array, real or complex, shape (M,M)
- The computed self-energy. Note that even if `h_cell` and `h_hop` are
- both real, `Sigma` will typically be complex. (More precisely, if there
- is a propagating mode, `Sigma` will definitely be complex.)
-
- Notes
- -----
- For simplicity this function relies on the calculation of modes as input.
- This may cause a small slowdown, and can be improved if necessary.
- """
- vecs, vecslmbdainv, nmodes, v = lead_modes
- vecs = vecs[:, nmodes:]
- vecslmbdainv = vecslmbdainv[:, nmodes:]
- if v is not None:
- return dot(v, dot(vecs, la.solve(vecslmbdainv, v.T.conj())))
- else:
- return la.solve(vecslmbdainv.T, vecs.T).T
-
-
def selfenergy(h_cell, h_hop, tol=1e6):
"""
Compute the self-energy generated by the lead.
@@ -655,7 +642,8 @@ def selfenergy(h_cell, h_hop, tol=1e6):
For simplicity this function internally calculates the modes first.
This may cause a small slowdown, and can be improved if necessary.
"""
- return selfenergy_from_modes(modes(h_cell, h_hop, tol)[1])
+ propagating, stabilized = modes(h_cell, h_hop, tol)
+ return stabilized.selfenergy()
def square_selfenergy(width, hopping, fermi_energy):
diff --git a/kwant/system.py b/kwant/system.py
index cb22be259cc4a52300915c0cf825a6a6341de67f..2a69650a9439cd56802cb93a7772b3ce585145c9 100644
--- a/kwant/system.py
+++ b/kwant/system.py
@@ -102,7 +102,9 @@ class FiniteSystem(System):
Numbers of the leads to be precalculated. If `None`, all are
precalculated.
calculate_selfenergy : bool
- Whether to calculate self-energy if modes are available.
+ Whether to calculate self-energy if modes are available. Defaults
+ to `False`. Disabling this saves a typically negligible amount of
+ time and memory.
Returns
-------
@@ -127,7 +129,7 @@ class FiniteSystem(System):
try:
modes = lead.modes(energy, args)
if calculate_selfenergy:
- selfenergy = physics.selfenergy_from_modes(modes)
+ selfenergy = modes[1].selfenergy()
except AttributeError:
selfenergy = lead.selfenergy(energy, args)
new_leads.append(PrecalculatedLead(modes, selfenergy))