Allow TimeDerivative(p::Process).

Datseris · Datseris · commit d924b4a858fd · 2025-04-11T10:13:01.000+01:00
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -3,6 +3,10 @@
 ProcessBasedModelling.jl follows semver 2.0.
 Changelog is kept with respect to v1 release.
 
+## 1.4
+
+- Allow `TimeDerivative(p::Process)`.
+
 ## 1.3
 
 - Better error messages for duplicate processes given to `process_to_mtkmodel`.
diff --git a/Project.toml b/Project.toml
@@ -1,7 +1,7 @@
 name = "ProcessBasedModelling"
 uuid = "ca969041-2cf3-4b10-bc21-86f4417093eb"
 authors = ["Datseris <datseris.george@gmail.com>"]
-version = "1.3.1"
+version = "1.4.0"
 
 [deps]
 ModelingToolkit = "961ee093-0014-501f-94e3-6117800e7a78"
diff --git a/src/processes_basic.jl b/src/processes_basic.jl
@@ -48,6 +48,13 @@ TimeDerivative(a, b) = TimeDerivative(a, b, nothing)
 timescale(e::TimeDerivative) = e.timescale
 rhs(e::TimeDerivative) = e.expression
 
+"""
+    TimeDerivative(p::Process [, τ])
+
+Turn an existing process into a time derivative by creating
+`τ * Differential(t)(LHS(p)) ~ RHS(p)`.
+"""
+TimeDerivative(p::Process, t = nothing) = TimeDerivative(lhs(p), rhs(p), τ)
 
 """
     ExpRelaxation(variable, expression [, τ]) <: Process
