SBML import: support == operator (#2708)

* SBML import: support `==` operator

Adds support the the equality operator in piecewise conditions or event triggers.

* Update SBML test suite results

This is the combined increase from using sbmlmath, supporting xor, and supporting ==.

Author: dweindl

doc/python_interface.rst

@@ -26,7 +26,7 @@ AMICI can import :term:`SBML` models via the
 Status of SBML support in Python-AMICI
 ++++++++++++++++++++++++++++++++++++++
 
-Python-AMICI currently **passes 1252 out of the 1821 (~68%) test cases** from
+Python-AMICI currently **passes 1268 out of the 1821 (~70%) test cases** from
 the semantic
 `SBML Test Suite <https://github.com/sbmlteam/sbml-test-suite/>`_
 (`current status <https://github.com/AMICI-dev/AMICI/actions>`_).

python/sdist/amici/import_utils.py

@@ -533,8 +533,8 @@ def _parse_heaviside_trigger(trigger: sp.Expr) -> sp.Expr:
 
     # rewrite n-ary XOR to OR to be handled below:
     trigger = trigger.replace(sp.Xor, _xor_to_or)
-
-    # TODO: x == y
+    # rewrite equality
+    trigger = trigger.replace(sp.Eq, _eq_to_and)
 
     # or(x,y) = not(and(not(x),not(y))
     if isinstance(trigger, sp.Or):
@@ -573,6 +573,18 @@ def _xor_to_or(*args):
     return res.simplify()
 
 
+def _eq_to_and(*args):
+    """
+    Replace equality expression with numerical arguments by inequalities.
+
+    ``Eq(x, y) = (x >= y) & (x <= y)``.
+
+    to be used in ``trigger = trigger.replace(sp.Eq, _eq_to_and)``.
+    """
+    x, y = args
+    return (x >= y) & (x <= y)
+
+
 def grouper(
     iterable: Iterable, n: int, fillvalue: Any = None
 ) -> Iterable[tuple[Any]]:

python/sdist/amici/sbml_import.py

@@ -53,6 +53,7 @@
     generate_flux_symbol,
     _parse_piecewise_to_heaviside,
     _xor_to_or,
+    _eq_to_and,
 )
 from .logging import get_logger, log_execution_time, set_log_level
 from .sbml_utils import SBMLException
@@ -3216,6 +3217,8 @@ def _parse_event_trigger(trigger: sp.Expr) -> sp.Expr:
 
     # rewrite n-ary XOR to OR to be handled below:
     trigger = trigger.replace(sp.Xor, _xor_to_or)
+    # rewrite equality
+    trigger = trigger.replace(sp.Eq, _eq_to_and)
 
     # or(x,y): any of {x,y} is > 0: sp.Max(x, y)
     if isinstance(trigger, sp.Or):