From 19d3344dd372993c053ef9d76099646e2ca724e5 Mon Sep 17 00:00:00 2001
From: dkapraun <kapraun.dustin@epa.gov>
Date: Tue, 25 Nov 2025 15:44:27 -0500
Subject: [PATCH] Ensure that multiple different models can be used in the same
 R session.

---
 DESCRIPTION        |  2 +-
 R/MCSim_model.R    | 29 ++++++++++++++----
 R/compileModel.R   | 73 +++++++++++++++++++++++++++++++++++++++++++++-
 man/Model-class.Rd |  2 +-
 4 files changed, 97 insertions(+), 9 deletions(-)

diff --git a/DESCRIPTION b/DESCRIPTION
index 257db47..56d9eed 100644
--- a/DESCRIPTION
+++ b/DESCRIPTION
@@ -1,6 +1,6 @@
 Package: MCSimMod
 Title: Working with 'MCSim' Models
-Version: 1.1
+Version: 1.1.9000
 Authors@R: c(
   person("Dustin F.", "Kapraun", role=c("aut", "cre"), email = "kapraun.dustin@epa.gov", comment = c(ORCID = "0000-0001-5570-6383")),
   person("Todd J.", "Zurlinden", role="aut", comment = c(ORCID = "0000-0003-1372-3913")),
diff --git a/R/MCSim_model.R b/R/MCSim_model.R
index 18a5c86..dca67ff 100644
--- a/R/MCSim_model.R
+++ b/R/MCSim_model.R
@@ -106,10 +106,24 @@ Model <- setRefClass("Model",
 
       # Run script that defines initialization functions.
       source(paths$inits_file, local = TRUE)
-      initParms <<- initParms
-      initStates <<- initStates
 
-      Outputs <<- Outputs
+      # Associate initParms for this model with the initParms function defined
+      # in inits_file.
+      r_command_string <- paste0("initParms <<- initParms_", mName)
+      r_expression <- parse(text = r_command_string)
+      eval(r_expression)
+
+      # Associate initStates for this model with the initStates function defined
+      # in inits_file.
+      r_command_string <- paste0("initStates <<- initStates_", mName)
+      r_expression <- parse(text = r_command_string)
+      eval(r_expression)
+
+      # Associate Outputs for this model with the Outputs variable defined in
+      # inits_file.
+      r_command_string <- paste0("Outputs <<- Outputs_", mName)
+      r_expression <- parse(text = r_command_string)
+      eval(r_expression)
 
       parms <<- initParms()
       Y0 <<- initStates(parms)
@@ -125,10 +139,13 @@ Model <- setRefClass("Model",
     runModel = function(times, ...) {
       "Perform a simulation for the Model object using the \\code{deSolve} function \\code{ode} for the specified \\code{times}."
       # Solve the ODE system using the "ode" function from the package "deSolve".
+      derivs_name <- paste0("derivs_", mName)
+      initforc_name <- paste0("initforc_", mName)
+      initmod_name <- paste0("initmod_", mName)
       out <- ode(Y0, times,
-        func = "derivs", parms = parms, dllname = paths$dll_name,
-        initforc = "initforc", initfunc = "initmod", nout = length(Outputs),
-        outnames = Outputs, ...
+        func = derivs_name, parms = parms, dllname = paths$dll_name,
+        initforc = initforc_name, initfunc = initmod_name,
+        nout = length(Outputs), outnames = Outputs, ...
       )
 
       # Return the simulation output.
diff --git a/R/compileModel.R b/R/compileModel.R
index ff6204a..cef24fd 100644
--- a/R/compileModel.R
+++ b/R/compileModel.R
@@ -16,7 +16,11 @@
 #' @export
 compileModel <- function(model_file, c_file, dll_name, dll_file, hash_file = NULL, verbose_output = FALSE) {
   # Unload DLL if it has been loaded.
-  if (is.loaded("derivs", PACKAGE = dll_name)) {
+  mList <- .fixPath(model_file)
+  model_name <- mList$mName
+  model_path <- mList$mPath
+  derivs_name <- paste0("derivs_", model_name)
+  if (is.loaded(derivs_name, PACKAGE = dll_name)) {
     dyn.unload(dll_file)
   }
 
@@ -92,6 +96,73 @@ compileModel <- function(model_file, c_file, dll_name, dll_file, hash_file = NUL
     }
   }
 
+  # Code to update C source file using model-specific names for objects.
+
+  # Read the original C source file.
+  lines <- readLines(c_file)
+
+  # Find and replace C object names with model-specific names.
+  item_to_replace <- c(
+    "parms",
+    "forc",
+    "Nout",
+    "nr",
+    "ytau",
+    "yini",
+    "lagvalue",
+    "CalcDelay",
+    "initmod",
+    "initforc",
+    "initState",
+    "getParms",
+    "derivs",
+    "jac",
+    "event",
+    "root"
+  )
+  for (idx in seq(length(item_to_replace))) {
+    lines <- gsub(
+      paste0("\\b", item_to_replace[idx], "\\b"),
+      paste0(item_to_replace[idx], "_", model_name),
+      lines
+    )
+  }
+
+  # Overwrite the C source file with the updated text.
+  writeLines(lines, c_file)
+
+
+  # Code to update inits R source file using model-specific names for objects.
+
+  # Get inits R source file name.
+  inits_file <- file.path(
+    model_path,
+    paste0(model_name, "_model_inits.R")
+  )
+
+  # Read the original inits R source file.
+  lines <- readLines(inits_file)
+
+  # Find and replace R and C object names with model-specific names.
+  item_to_replace <- c(
+    "initParms",
+    "getParms",
+    "Outputs",
+    "initStates",
+    "initState"
+  )
+  for (idx in seq(length(item_to_replace))) {
+    lines <- gsub(
+      paste0("\\b", item_to_replace[idx], "\\b"),
+      paste0(item_to_replace[idx], "_", model_name),
+      lines
+    )
+  }
+
+  # Overwrite the R inits source file with the updated text.
+  writeLines(lines, inits_file)
+
+
   # Compile the C model to obtain an object file (ending with ".o") and a
   # machine code file (ending with ".dll" or ".so"). Write compiler output
   # to a character string.
diff --git a/man/Model-class.Rd b/man/Model-class.Rd
index 83947f1..1925d91 100644
--- a/man/Model-class.Rd
+++ b/man/Model-class.Rd
@@ -65,6 +65,6 @@ expression \code{mod$updateParms()}. Use the \code{createModel()} function to cr
 
 \item{\code{updateParms(new_parms = NULL)}}{Update values of parameters for the Model object.}
 
-\item{\code{updateY0(new_states = NULL)}}{Update values of initital conditions of state variables for the Model object.}
+\item{\code{updateY0(new_states = NULL)}}{Update values of initial conditions of state variables for the Model object.}
 }}