From 0befa493fd7570b473a54cc9d07e9f8498aacf08 Mon Sep 17 00:00:00 2001
From: Anton Akhmerov <anton.akhmerov@gmail.com>
Date: Thu, 2 Nov 2023 20:02:43 +0100
Subject: [PATCH] make e positive, fixes #48
---
qsymm/kwant_continuum.py | 3 +++
qsymm/model.py | 6 +++---
2 files changed, 6 insertions(+), 3 deletions(-)
diff --git a/qsymm/kwant_continuum.py b/qsymm/kwant_continuum.py
index c2e5695..7d16e30 100644
--- a/qsymm/kwant_continuum.py
+++ b/qsymm/kwant_continuum.py
@@ -51,6 +51,7 @@ import warnings
momentum_operators = sympy.symbols('k_x k_y k_z', commutative=False)
position_operators = sympy.symbols('x y z', commutative=False)
+e = sympy.symbols('e', positive=True)
pauli = [sympy.eye(2), _msigma(1), _msigma(2), _msigma(3)]
@@ -217,6 +218,8 @@ def sympify(expr, locals=None):
# sympify we are getting list of sympy objects, so we call sympify
# second time to obtain ``sympy`` matrices.
hamiltonian = sympy.sympify(hamiltonian)
+ # A workaround for qsymm issue #48
+ hamiltonian = hamiltonian.subs(sympy.sympify('e'), e)
finally:
if stored_value is not None:
converter[list] = stored_value
diff --git a/qsymm/model.py b/qsymm/model.py
index 63b1458..1cbcf49 100644
--- a/qsymm/model.py
+++ b/qsymm/model.py
@@ -19,8 +19,8 @@ from . import kwant_continuum
_commutative_momenta = [kwant_continuum.make_commutative(k, k)
for k in kwant_continuum.momentum_operators]
-e = kwant_continuum.sympify('e')
-I = kwant_continuum.sympify('I') # noqa: E741
+e = kwant_continuum.e
+I = sympy.I # noqa: E741
def substitute_exponents(expr):
@@ -990,7 +990,7 @@ def _find_momenta(momenta):
@lru_cache(maxsize=1000)
def _symbol_normalizer(key):
- return sympy.expand_power_exp(sympy.sympify(key))
+ return sympy.expand_power_exp(sympy.sympify(key, locals={'e': e}))
@lru_cache(maxsize=1000)
--
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