Lazy loading of Julia things

Makefile

@@ -64,15 +64,15 @@ eg0: all
 	rm -rf testing/eg0/*
 	cp examples/rmg/superminimal/input.py testing/eg0/input.py
 	@ echo "Running eg0: superminimal (H2 oxidation) example"
-	RMG_DISABLE_JULIA=1 python rmg.py testing/eg0/input.py
+	python rmg.py testing/eg0/input.py
 
 eg1: all
 	mkdir -p testing/eg1
 	rm -rf testing/eg1/*
 	cp examples/rmg/minimal/input.py testing/eg1/input.py
 	coverage erase
 	@ echo "Running eg1: minimal (ethane pyrolysis) example with coverage tracking AND profiling"
-	RMG_DISABLE_JULIA=1 coverage run rmg.py -p testing/eg1/input.py
+	coverage run rmg.py -p testing/eg1/input.py
 	coverage report
 	coverage html
 
@@ -82,44 +82,44 @@ eg2: all
 	cp examples/rmg/1,3-hexadiene/input.py testing/eg2/input.py
 	coverage erase
 	@ echo "Running eg2: 1,3-hexadiene example with profiling"
-	RMG_DISABLE_JULIA=1 python rmg.py -p testing/eg2/input.py
+	python rmg.py -p testing/eg2/input.py
 
 eg3: all
 	mkdir -p testing/eg3
 	rm -rf testing/eg3/*
 	cp examples/rmg/liquid_phase/input.py testing/eg3/input.py
 	coverage erase
 	@ echo "Running eg3: liquid_phase example with profiling"
-	RMG_DISABLE_JULIA=1 python rmg.py -p testing/eg3/input.py
+	python rmg.py -p testing/eg3/input.py
 
 eg5: all
 	mkdir -p testing/eg5
 	rm -rf testing/eg5/*
 	cp examples/rmg/heptane-eg5/input.py testing/eg5/input.py
 	@ echo "Running eg5: heptane example"
-	RMG_DISABLE_JULIA=1 python rmg.py testing/eg5/input.py
+	python rmg.py testing/eg5/input.py
 
 eg6: all
 	mkdir -p testing/eg6
 	rm -rf testing/eg6/*
 	cp examples/rmg/ethane-oxidation/input.py testing/eg6/input.py
 	@ echo "Running eg6: ethane-oxidation example"
-	RMG_DISABLE_JULIA=1 python rmg.py testing/eg6/input.py
+	python rmg.py testing/eg6/input.py
 
 eg7: all
 	mkdir -p testing/eg7
 	rm -rf testing/eg7/*
 	cp examples/rmg/gri_mech_rxn_lib/input.py testing/eg7/input.py
 	@ echo "Running eg7: gri_mech_rxn_lib example"
-	RMG_DISABLE_JULIA=1 python rmg.py testing/eg7/input.py
+	python rmg.py testing/eg7/input.py
 
 scoop: all
 	mkdir -p testing/scoop
 	rm -rf testing/scoop/*
 	cp examples/rmg/minimal/input.py testing/scoop/input.py
 	coverage erase
 	@ echo "Running minimal example with SCOOP"
-	RMG_DISABLE_JULIA=1 python -m scoop -n 2 rmg.py -v testing/scoop/input.py
+	python -m scoop -n 2 rmg.py -v testing/scoop/input.py
 
 eg4: all
 	mkdir -p testing/eg4

rmgpy/pdep/sls.py

@@ -33,29 +33,42 @@
 """
 
 import logging
-import sys
+import os
 
 import numpy as np
 import scipy.linalg
 import scipy.optimize as opt
-import scipy.sparse as sparse
 
+import rmgpy
 import rmgpy.constants as constants
 from rmgpy.pdep.me import generate_full_me_matrix, states_to_configurations
 from rmgpy.rmg.reactionmechanismsimulator_reactors import to_julia
 
-NO_JULIA = False
-try:
-    from juliacall import Main
+class MainProxy:
+    """
+    A proxy for the juliacall Main module, that will replace itself
+    with the real thing the first time it's accessed.
+    This is to delay loading Julia until it's really needed.
+    """
+    def __getattr__(self, name):
+        if hasattr(rmgpy, 'DISABLE_JULIA') and rmgpy.DISABLE_JULIA:
+            raise ImportError("Julia imports disabled via rmgpy.DISABLE_JULIA flag")
+        elif os.environ.get('RMG_DISABLE_JULIA', '').lower() in ('1', 'true', 'yes'):
+            raise ImportError("Julia imports disabled via RMG_DISABLE_JULIA environment variable")
+
+        try:
+            from juliacall import Main as JuliaMain
+            Main = JuliaMain
+            Main.seval("using ReactionMechanismSimulator.SciMLBase")
+            Main.seval("using ReactionMechanismSimulator.Sundials")
+        except Exception as e:
+            logging.error("Failed to import Julia and load ReactionMechanismSimulator components needed.")
+            raise
+        globals()['Main'] = JuliaMain  # Replace proxy with real thing, for next time it's called
+        return getattr(JuliaMain, name) # Return the attribute for the first time it's called
+
+Main = MainProxy()
 
-    Main.seval("using ReactionMechanismSimulator.SciMLBase")
-    Main.seval("using ReactionMechanismSimulator.Sundials")
-except Exception as e:
-    logging.info(
-        f"Unable to import Julia dependencies, original error: {str(e)}"
-        ". Master equation method 'ode' will not be available on this execution."
-    )
-    NO_JULIA = True
 
 
 def get_initial_condition(network, x0, indices):
@@ -167,11 +180,6 @@ def get_rate_coefficients_SLS(network, T, P, method="mexp", neglect_high_energy_
     tau = np.abs(1.0 / fastest_reaction)
 
     if method == "ode":
-        if NO_JULIA:
-            raise RuntimeError(
-                "Required Julia dependencies for method 'ode' are not installed.\n"
-                "Please follow the steps to install Julia dependencies at https://reactionmechanismgenerator.github.io/RMG-Py/users/rmg/installation/anacondaDeveloper.html."
-            )
         f = Main.seval(
             """
 function f(du, u, M, t)

rmgpy/rmg/input.py

@@ -47,7 +47,6 @@
 from rmgpy.quantity import Energy, Quantity, RateCoefficient, SurfaceConcentration
 from rmgpy.rmg.model import CoreEdgeReactionModel
 from rmgpy.rmg.reactionmechanismsimulator_reactors import (
-    NO_JULIA,
     ConstantTLiquidSurfaceReactor,
     ConstantTPIdealGasReactor,
     ConstantTVLiquidReactor,
@@ -1593,11 +1592,6 @@ def read_input_file(path, rmg0):
         exec(f.read(), global_context, local_context)
     except (NameError, TypeError, SyntaxError) as e:
         logging.error('The input file "{0}" was invalid:'.format(full_path))
-        if NO_JULIA:
-            logging.error(
-                "During runtime, import of Julia dependencies failed. To use phase systems and RMS reactors, install RMG-Py with RMS."
-                " (https://reactionmechanismgenerator.github.io/RMG-Py/users/rmg/installation/anacondaDeveloper.html)"
-            )
         logging.exception(e)
         raise
     finally:

rmgpy/rmg/main.py

@@ -75,7 +75,6 @@
 from rmgpy.rmg.model import CoreEdgeReactionModel, Species
 from rmgpy.rmg.output import OutputHTMLWriter
 from rmgpy.rmg.pdep import PDepNetwork, PDepReaction
-from rmgpy.rmg.reactionmechanismsimulator_reactors import NO_JULIA
 from rmgpy.rmg.reactionmechanismsimulator_reactors import Reactor as RMSReactor
 from rmgpy.rmg.settings import ModelSettings
 from rmgpy.solver.base import TerminationConversion, TerminationTime

rmgpy/rmg/model.py

@@ -57,7 +57,6 @@
 from rmgpy.rmg.pdep import PDepNetwork, PDepReaction
 from rmgpy.rmg.react import react_all
 from rmgpy.rmg.reactionmechanismsimulator_reactors import (
-    NO_JULIA,
     Interface,
     Phase,
     PhaseSystem,
@@ -81,7 +80,7 @@ def __init__(self, species=None, reactions=None, phases=None, interfaces={}):
         if phases is None:
             phases = {"Default": Phase(), "Surface": Phase()}
             interfaces = {frozenset({"Default", "Surface"}): Interface(list(phases.values()))}
-        self.phase_system = None if NO_JULIA else PhaseSystem(phases, interfaces)
+        self.phase_system = PhaseSystem(phases, interfaces)
 
     def __reduce__(self):
         """
@@ -355,7 +354,7 @@ def make_new_species(self, object, label="", reactive=True, check_existing=True,
         orilabel = spec.label
         label = orilabel
         i = 2
-        if self.edge.phase_system:  # None when RMS not installed
+        if self.edge.phase_system:  # !!! Not maintained when operating with require_rms=False?
             while any([label in phase.names for phase in self.edge.phase_system.phases.values()]):
                 label = orilabel + "-" + str(i)
                 i += 1

rmgpy/rmg/reactionmechanismsimulator_reactors.py

@@ -35,6 +35,7 @@
 import os
 
 import numpy as np
+import rmgpy
 
 from rmgpy.data.solvation import SolventData
 from rmgpy.kinetics.arrhenius import (
@@ -59,25 +60,32 @@
 from rmgpy.thermo.nasa import NASA, NASAPolynomial
 from rmgpy.thermo.thermodata import ThermoData
 
+class MainProxy:
+    """
+    A proxy for the juliacall Main module, that will replace itself
+    with the real thing the first time it's accessed.
+    This is to delay loading Julia until it's really needed.
+    """
+    def __getattr__(self, name):
+        if hasattr(rmgpy, 'DISABLE_JULIA') and rmgpy.DISABLE_JULIA:
+            raise ImportError("Julia imports disabled via rmgpy.DISABLE_JULIA flag")
+        elif os.environ.get('RMG_DISABLE_JULIA', '').lower() in ('1', 'true', 'yes'):
+            raise ImportError("Julia imports disabled via RMG_DISABLE_JULIA environment variable")
 
-NO_JULIA = True
-
-# Check if Julia should be disabled via module-level variable or environment variable
-import rmgpy
-if hasattr(rmgpy, 'DISABLE_JULIA') and rmgpy.DISABLE_JULIA:
-    logging.info("Julia imports disabled via rmgpy.DISABLE_JULIA flag")
-elif os.environ.get('RMG_DISABLE_JULIA', '').lower() in ('1', 'true', 'yes'):
-    logging.info("Julia imports disabled via RMG_DISABLE_JULIA environment variable")
-else:
-    try:
-        from juliacall import Main
-        Main.seval("using PythonCall")
-        Main.seval("using ReactionMechanismSimulator")
-        Main.seval("using ReactionMechanismSimulator.Sundials")
-        NO_JULIA = False
-    except ImportError as e:
-        logging.warning("Julia import failed, RMS reactors not available. "
-                       "Exception: %s", str(e))
+        try:
+            from juliacall import Main as JuliaMain
+            Main = JuliaMain
+            Main.seval("using PythonCall")
+            Main.seval("using ReactionMechanismSimulator")
+            Main.seval("using ReactionMechanismSimulator.Sundials")
+        except Exception as e:
+            logging.error("Failed to import Julia and load ReactionmechanismSimulator. "
+                          "To use phase systems and RMS reactors, install RMG-Py with RMS.")
+            logging.exception(e)
+            raise
+        globals()['Main'] = JuliaMain  # Replace proxy with real thing, for next time it's called
+        return getattr(JuliaMain, name) # Return the attribute for the first time it's called
+Main = MainProxy()
 
 
 def to_julia(obj):
@@ -95,6 +103,7 @@ def to_julia(obj):
     object : Main.Dict | Main.Vector | Main.Matrix | object
         The Julia object
     """
+
     if isinstance(obj, dict):
         return Main.PythonCall.pyconvert(Main.Dict, obj)
     elif isinstance(obj, (list, np.ndarray)):