From a5f9532cecb9f5421984327c06709470af5e5f5e Mon Sep 17 00:00:00 2001
From: marinlauber <marinlauber@gmail.com>
Date: Fri, 25 Jul 2025 13:41:56 +0200
Subject: [PATCH 1/5] add julia resonant circuit example

---
 resonant-circuit/capacitor-julia/Project.toml |   3 +
 resonant-circuit/capacitor-julia/capacitor.jl |  90 +++++++++++++++
 resonant-circuit/capacitor-julia/run.sh       |   3 +
 resonant-circuit/coil-julia/Project.toml      |   3 +
 resonant-circuit/coil-julia/coil.jl           | 107 ++++++++++++++++++
 resonant-circuit/coil-julia/run.sh            |   3 +
 6 files changed, 209 insertions(+)
 create mode 100644 resonant-circuit/capacitor-julia/Project.toml
 create mode 100644 resonant-circuit/capacitor-julia/capacitor.jl
 create mode 100755 resonant-circuit/capacitor-julia/run.sh
 create mode 100644 resonant-circuit/coil-julia/Project.toml
 create mode 100644 resonant-circuit/coil-julia/coil.jl
 create mode 100755 resonant-circuit/coil-julia/run.sh

diff --git a/resonant-circuit/capacitor-julia/Project.toml b/resonant-circuit/capacitor-julia/Project.toml
new file mode 100644
index 000000000..8a303cd38
--- /dev/null
+++ b/resonant-circuit/capacitor-julia/Project.toml
@@ -0,0 +1,3 @@
+[deps]
+OrdinaryDiffEq = "1dea7af3-3e70-54e6-95c3-0bf5283fa5ed"
+PreCICE = "57fbd4af-5cc3-4712-aac0-6930e7658184"
diff --git a/resonant-circuit/capacitor-julia/capacitor.jl b/resonant-circuit/capacitor-julia/capacitor.jl
new file mode 100644
index 000000000..3e97adbf2
--- /dev/null
+++ b/resonant-circuit/capacitor-julia/capacitor.jl
@@ -0,0 +1,90 @@
+using PreCICE
+using OrdinaryDiffEq
+using JLD2
+
+# Initialize and configure preCICE
+participant = PreCICE.createParticipant("Capacitor", "../precice-config.xml", 0, 1)
+
+# Geometry IDs. As it is a 0-D simulation, only one vertex is necessary.
+mesh_name = "Capacitor-Mesh"
+
+dimensions = PreCICE.getMeshDimensions(mesh_name)
+
+vertex_ids = PreCICE.setMeshVertices(mesh_name, [0. 0.])
+
+let
+    # Data IDs
+    read_data_name = "Current"
+    write_data_name = "Voltage"
+
+    # Simulation parameters and initial condition
+    C = 2                         # Capacitance of the capacitor
+    L = 1                         # Inductance of the coil
+    t0 = 0                        # Initial simulation time
+    t_max = 10                    # End simulation time
+    Io = 1                        # Initial current
+    phi = 0                       # Phase of the signal
+
+    w0 = 1 / sqrt(L * C)          # Resonant frequency
+    U0 = -w0 * L * Io * sin(phi)  # Initial condition for U
+
+    function f_U(u, p, t)
+        (dt, C, mesh_name, read_data_name, vertex_ids) = p
+        I = PreCICE.readData(mesh_name, read_data_name, vertex_ids, dt)
+        return -I[1] / C      # Time derivative of U
+    end
+
+    # Initialize simulation
+    if PreCICE.requiresInitialData()
+        @show I0
+        PreCICE.writeData(mesh_name, write_data_name, vertex_ids, I0)
+    end
+    PreCICE.initialize()
+
+    solver_dt = PreCICE.getMaxTimeStepSize()
+
+    # Start simulation
+    t = t0
+    U0_checkpoint = U0
+    t_checkpoint = t
+    U_store = [[t, U0]]
+    while PreCICE.isCouplingOngoing()
+
+
+        # Record checkpoint if necessary
+        if PreCICE.requiresWritingCheckpoint()
+            U0_checkpoint = U0
+            t_checkpoint = t
+        end
+
+        # Make Simulation Step
+        precice_dt = PreCICE.getMaxTimeStepSize()
+        dt = min(precice_dt, solver_dt)
+        t_span = (t, t + dt)
+        params = (dt, C, mesh_name, read_data_name, vertex_ids)
+        prob = ODEProblem(f_U, U0, t_span, params)
+        # https://docs.sciml.ai/DiffEqDocs/stable/basics/common_solver_opts
+        sol = solve(prob, Tsit5(), reltol=1e-12, abstol=1e-12)
+
+        # Exchange data
+        evals = max(length(sol.t), 3)  # at least do 3 substeps to allow cubic interpolation
+        for i in range(1,evals)
+            U0 = sol(t_span[1] + i * dt / evals)
+            PreCICE.writeData(mesh_name, write_data_name, vertex_ids, fill(U0, (1,1)))
+            PreCICE.advance(dt / evals)
+        end
+        t = t + dt
+
+        # Recover checkpoint if not converged
+        if PreCICE.requiresReadingCheckpoint()
+            U0 = U0_checkpoint
+            t = t_checkpoint
+        end
+        if PreCICE.isTimeWindowComplete()
+            push!(U_store, [t, U0])
+        end
+    end
+    jldsave("capacitor.jld2", U=U_store)
+    # Stop coupling
+    PreCICE.finalize()
+end
\ No newline at end of file
diff --git a/resonant-circuit/capacitor-julia/run.sh b/resonant-circuit/capacitor-julia/run.sh
new file mode 100755
index 000000000..b8fad8705
--- /dev/null
+++ b/resonant-circuit/capacitor-julia/run.sh
@@ -0,0 +1,3 @@
+#!/bin/sh
+
+julia --project=. capacitor.jl
\ No newline at end of file
diff --git a/resonant-circuit/coil-julia/Project.toml b/resonant-circuit/coil-julia/Project.toml
new file mode 100644
index 000000000..8a303cd38
--- /dev/null
+++ b/resonant-circuit/coil-julia/Project.toml
@@ -0,0 +1,3 @@
+[deps]
+OrdinaryDiffEq = "1dea7af3-3e70-54e6-95c3-0bf5283fa5ed"
+PreCICE = "57fbd4af-5cc3-4712-aac0-6930e7658184"
diff --git a/resonant-circuit/coil-julia/coil.jl b/resonant-circuit/coil-julia/coil.jl
new file mode 100644
index 000000000..00c192ec0
--- /dev/null
+++ b/resonant-circuit/coil-julia/coil.jl
@@ -0,0 +1,107 @@
+using PreCICE
+using OrdinaryDiffEq
+using Plots
+using JLD2
+
+# Initialize and configure preCICE
+participant = PreCICE.createParticipant("Coil", "../precice-config.xml", 0, 1)
+
+# Geometry IDs. As it is a 0-D simulation, only one vertex is necessary.
+mesh_name = "Coil-Mesh"
+
+dimensions = PreCICE.getMeshDimensions(mesh_name)
+
+vertex_ids = PreCICE.setMeshVertices(mesh_name, [0. 0.])
+
+let
+    # Data IDs
+    read_data_name = "Voltage"
+    write_data_name = "Current"
+
+    # Simulation parameters and initial condition
+    C = 2                      # Capacitance of the capacitor
+    L = 1                      # Inductance of the coil
+    t0 = 0                     # Initial simulation time
+    Io = 1                     # Initial current
+    phi = 0                    # Phase of the signal
+
+    w0 = 1 / sqrt(L * C)       # Resonant frequency
+    I0 = Io * cos(phi)         # Initial condition for I
+
+    # to estimate cost
+    f_evals = 0
+
+    function f_I(u, p, t)
+        f_evals += 1
+        (dt, L, mesh_name, read_data_name, vertex_ids) = p
+        U = PreCICE.readData(mesh_name, read_data_name, vertex_ids, dt)
+        return U[1] / L  # Time derivative of I; ODE determining capacitor
+    end
+
+    # Initialize simulation
+    if PreCICE.requiresInitialData()
+        @show I0
+        PreCICE.writeData(mesh_name, write_data_name, vertex_ids, I0)
+    end
+    PreCICE.initialize()
+
+    solver_dt = PreCICE.getMaxTimeStepSize()
+
+    # Start simulation
+    t = t0
+    I0_checkpoint = I0
+    t_checkpoint = t
+    I_store = [[t, I0]]
+    while PreCICE.isCouplingOngoing()
+
+        # Record checkpoint if necessary
+        if PreCICE.requiresWritingCheckpoint()
+            I0_checkpoint = I0
+            t_checkpoint = t
+        end
+
+        # Make Simulation Step
+        precice_dt = PreCICE.getMaxTimeStepSize()
+        dt = min(precice_dt, solver_dt)
+        t_span = (t, t + dt)
+        params = (dt, L, mesh_name, read_data_name, vertex_ids)
+        prob = ODEProblem(f_I, I0, t_span, params)
+        # https://docs.sciml.ai/DiffEqDocs/stable/basics/common_solver_opts
+        sol = solve(prob, Tsit5(), reltol=1e-12, abstol=1e-12)
+
+        # Exchange data
+        evals = max(length(sol.t), 3)  # at least do 3 substeps to allow cubic interpolation
+        for i in range(1,evals)
+            I0 = sol(t_span[1] + i * dt / evals)
+            PreCICE.writeData(mesh_name, write_data_name, vertex_ids, fill(I0, (1,1)))
+            PreCICE.advance(dt / evals)
+        end
+        t = t + dt
+
+        # Recover checkpoint if not converged
+        if PreCICE.requiresReadingCheckpoint()
+            I0 = I0_checkpoint
+            t = t_checkpoint
+        end
+        if PreCICE.isTimeWindowComplete()
+            push!(I_store, [t, I0])
+        end
+    end
+    jldsave("coil.jld2", U=I_store)
+    # Stop coupling
+    PreCICE.finalize()
+
+    # solutions
+    I_analytical(t) = Io * cos(t * w0 + phi)
+    U_analytical(t) = -w0 * L * Io * sin(w0 * t + phi);
+
+    # plot
+    time = getindex.(I_store,1); I_num = getindex.(I_store,2)
+    plot(time, [I_num, I_analytical.(time), U_analytical.(time)],
+         label=["Simulated Current" "Analytical Current" "Analytical Voltage"],
+         xlabel="Time", title="Resonant Circuit Simulation")
+    U_store = jldopen(joinpath(@__DIR__,"../capacitor-julia/capacitor.jld2"))
+    time = getindex.(U_store["U"],1); U_num = getindex.(U_store["U"],2)
+    plot!(time, U_num, label="Simulated Voltage")
+    savefig("resonant_circuit.png")
+end
\ No newline at end of file
diff --git a/resonant-circuit/coil-julia/run.sh b/resonant-circuit/coil-julia/run.sh
new file mode 100755
index 000000000..7d19bd1e8
--- /dev/null
+++ b/resonant-circuit/coil-julia/run.sh
@@ -0,0 +1,3 @@
+#!/bin/sh
+
+julia --project=. coil.jl
\ No newline at end of file

From 114d8115532f453c8fd3c0e34bb2eab54198c9aa Mon Sep 17 00:00:00 2001
From: marinlauber <marinlauber@gmail.com>
Date: Fri, 25 Jul 2025 14:37:31 +0200
Subject: [PATCH 2/5] update README.md

---
 resonant-circuit/README.md | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/resonant-circuit/README.md b/resonant-circuit/README.md
index fbbcbc4e9..ca2cb21fd 100644
--- a/resonant-circuit/README.md
+++ b/resonant-circuit/README.md
@@ -1,7 +1,7 @@
 ---
 title: Resonant Circuit
 permalink: tutorials-resonant-circuit.html
-keywords: MATLAB, Python
+keywords: MATLAB, Python, Julia
 summary: We simulate a two-element LC circuit (one inductor and one capacitor).
 ---
 
@@ -33,6 +33,7 @@ preCICE configuration (image generated using the [precice-config-visualizer](htt
 * *MATLAB* A solver using the [MATLAB bindings](https://precice.org/installation-bindings-matlab.html).
  Before running this tutorial, follow the [instructions](https://precice.org/installation-bindings-matlab.html) to correctly install the MATLAB bindings.
 * *Python* A solver using the preCICE [Python bindings](https://precice.org/installation-bindings-python.html).
+* *Julia* A solver using the preCICE [Julia bindings](https://precice.org/installation-bindings-julia.html).
 
 ## Running the simulation
 

From 64889d92ce3426f6537b5e5a41f849c070292d29 Mon Sep 17 00:00:00 2001
From: marinlauber <marinlauber@gmail.com>
Date: Wed, 6 Aug 2025 09:47:12 +0200
Subject: [PATCH 3/5] tidy scripts and remove plotting from there, fix run.sh

---
 resonant-circuit/capacitor-julia/capacitor.jl | 10 +-------
 resonant-circuit/capacitor-julia/run.sh       | 11 +++++++--
 resonant-circuit/coil-julia/coil.jl           | 24 +------------------
 resonant-circuit/coil-julia/run.sh            | 11 +++++++--
 4 files changed, 20 insertions(+), 36 deletions(-)

diff --git a/resonant-circuit/capacitor-julia/capacitor.jl b/resonant-circuit/capacitor-julia/capacitor.jl
index 3e97adbf2..175efe88e 100644
--- a/resonant-circuit/capacitor-julia/capacitor.jl
+++ b/resonant-circuit/capacitor-julia/capacitor.jl
@@ -1,6 +1,5 @@
 using PreCICE
 using OrdinaryDiffEq
-using JLD2
 
 # Initialize and configure preCICE
 participant = PreCICE.createParticipant("Capacitor", "../precice-config.xml", 0, 1)
@@ -10,7 +9,7 @@ mesh_name = "Capacitor-Mesh"
 
 dimensions = PreCICE.getMeshDimensions(mesh_name)
 
-vertex_ids = PreCICE.setMeshVertices(mesh_name, [0. 0.])
+vertex_ids = PreCICE.setMeshVertices(mesh_name, zeros((1,dimensions)))
 
 let
     # Data IDs
@@ -36,7 +35,6 @@ let
 
     # Initialize simulation
     if PreCICE.requiresInitialData()
-        @show I0
         PreCICE.writeData(mesh_name, write_data_name, vertex_ids, I0)
     end
     PreCICE.initialize()
@@ -47,10 +45,8 @@ let
     t = t0
     U0_checkpoint = U0
     t_checkpoint = t
-    U_store = [[t, U0]]
     while PreCICE.isCouplingOngoing()
 
-
         # Record checkpoint if necessary
         if PreCICE.requiresWritingCheckpoint()
             U0_checkpoint = U0
@@ -80,11 +76,7 @@ let
             U0 = U0_checkpoint
             t = t_checkpoint
         end
-        if PreCICE.isTimeWindowComplete()
-            push!(U_store, [t, U0])
-        end
     end
-    jldsave("capacitor.jld2", U=U_store)
     # Stop coupling
     PreCICE.finalize()
 end
\ No newline at end of file
diff --git a/resonant-circuit/capacitor-julia/run.sh b/resonant-circuit/capacitor-julia/run.sh
index b8fad8705..4e6b56f7b 100755
--- a/resonant-circuit/capacitor-julia/run.sh
+++ b/resonant-circuit/capacitor-julia/run.sh
@@ -1,3 +1,10 @@
-#!/bin/sh
+#!/usr/bin/env bash
+set -e -u
 
-julia --project=. capacitor.jl
\ No newline at end of file
+. ../../tools/log.sh
+exec > >(tee --append "$LOGFILE") 2>&1
+
+julia --project=Project.toml -e "using Pkg; Pkg.instantiate();"
+julia --project=Project.toml capacitor.jl
+
+close_log
\ No newline at end of file
diff --git a/resonant-circuit/coil-julia/coil.jl b/resonant-circuit/coil-julia/coil.jl
index 00c192ec0..38549a719 100644
--- a/resonant-circuit/coil-julia/coil.jl
+++ b/resonant-circuit/coil-julia/coil.jl
@@ -1,7 +1,5 @@
 using PreCICE
 using OrdinaryDiffEq
-using Plots
-using JLD2
 
 # Initialize and configure preCICE
 participant = PreCICE.createParticipant("Coil", "../precice-config.xml", 0, 1)
@@ -11,7 +9,7 @@ mesh_name = "Coil-Mesh"
 
 dimensions = PreCICE.getMeshDimensions(mesh_name)
 
-vertex_ids = PreCICE.setMeshVertices(mesh_name, [0. 0.])
+vertex_ids = PreCICE.setMeshVertices(mesh_name, zeros((1,dimensions)))
 
 let
     # Data IDs
@@ -40,7 +38,6 @@ let
 
     # Initialize simulation
     if PreCICE.requiresInitialData()
-        @show I0
         PreCICE.writeData(mesh_name, write_data_name, vertex_ids, I0)
     end
     PreCICE.initialize()
@@ -51,7 +48,6 @@ let
     t = t0
     I0_checkpoint = I0
     t_checkpoint = t
-    I_store = [[t, I0]]
     while PreCICE.isCouplingOngoing()
 
         # Record checkpoint if necessary
@@ -83,25 +79,7 @@ let
             I0 = I0_checkpoint
             t = t_checkpoint
         end
-        if PreCICE.isTimeWindowComplete()
-            push!(I_store, [t, I0])
-        end
     end
-    jldsave("coil.jld2", U=I_store)
     # Stop coupling
     PreCICE.finalize()
-
-    # solutions
-    I_analytical(t) = Io * cos(t * w0 + phi)
-    U_analytical(t) = -w0 * L * Io * sin(w0 * t + phi);
-
-    # plot
-    time = getindex.(I_store,1); I_num = getindex.(I_store,2)
-    plot(time, [I_num, I_analytical.(time), U_analytical.(time)],
-         label=["Simulated Current" "Analytical Current" "Analytical Voltage"],
-         xlabel="Time", title="Resonant Circuit Simulation")
-    U_store = jldopen(joinpath(@__DIR__,"../capacitor-julia/capacitor.jld2"))
-    time = getindex.(U_store["U"],1); U_num = getindex.(U_store["U"],2)
-    plot!(time, U_num, label="Simulated Voltage")
-    savefig("resonant_circuit.png")
 end
\ No newline at end of file
diff --git a/resonant-circuit/coil-julia/run.sh b/resonant-circuit/coil-julia/run.sh
index 7d19bd1e8..08a42b289 100755
--- a/resonant-circuit/coil-julia/run.sh
+++ b/resonant-circuit/coil-julia/run.sh
@@ -1,3 +1,10 @@
-#!/bin/sh
+#!/usr/bin/env bash
+set -e -u
 
-julia --project=. coil.jl
\ No newline at end of file
+. ../../tools/log.sh
+exec > >(tee --append "$LOGFILE") 2>&1
+
+julia --project=Project.toml -e "using Pkg; Pkg.instantiate();"
+julia --project=Project.toml coil.jl
+
+close_log
\ No newline at end of file

From 6d4bae9fcfb42a67e3a90e181fd1e5c02ad298a1 Mon Sep 17 00:00:00 2001
From: marinlauber <marinlauber@gmail.com>
Date: Wed, 6 Aug 2025 10:36:40 +0200
Subject: [PATCH 4/5] add package install in run and switch OrdinaryDiffEq for
 DifferentialEquations

---
 resonant-circuit/capacitor-julia/capacitor.jl | 2 +-
 resonant-circuit/capacitor-julia/run.sh       | 2 +-
 resonant-circuit/coil-julia/coil.jl           | 2 +-
 resonant-circuit/coil-julia/run.sh            | 2 +-
 4 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/resonant-circuit/capacitor-julia/capacitor.jl b/resonant-circuit/capacitor-julia/capacitor.jl
index 175efe88e..9219c5cae 100644
--- a/resonant-circuit/capacitor-julia/capacitor.jl
+++ b/resonant-circuit/capacitor-julia/capacitor.jl
@@ -1,5 +1,5 @@
 using PreCICE
-using OrdinaryDiffEq
+using DifferentialEquations
 
 # Initialize and configure preCICE
 participant = PreCICE.createParticipant("Capacitor", "../precice-config.xml", 0, 1)
diff --git a/resonant-circuit/capacitor-julia/run.sh b/resonant-circuit/capacitor-julia/run.sh
index 4e6b56f7b..a61d1fa67 100755
--- a/resonant-circuit/capacitor-julia/run.sh
+++ b/resonant-circuit/capacitor-julia/run.sh
@@ -4,7 +4,7 @@ set -e -u
 . ../../tools/log.sh
 exec > >(tee --append "$LOGFILE") 2>&1
 
-julia --project=Project.toml -e "using Pkg; Pkg.instantiate();"
+julia --project=Project.toml -e 'using Pkg; Pkg.add("DifferentialEquations"); Pkg.add("PreCICE"); Pkg.instantiate();'
 julia --project=Project.toml capacitor.jl
 
 close_log
\ No newline at end of file
diff --git a/resonant-circuit/coil-julia/coil.jl b/resonant-circuit/coil-julia/coil.jl
index 38549a719..6cd949ebb 100644
--- a/resonant-circuit/coil-julia/coil.jl
+++ b/resonant-circuit/coil-julia/coil.jl
@@ -1,5 +1,5 @@
 using PreCICE
-using OrdinaryDiffEq
+using DifferentialEquations
 
 # Initialize and configure preCICE
 participant = PreCICE.createParticipant("Coil", "../precice-config.xml", 0, 1)
diff --git a/resonant-circuit/coil-julia/run.sh b/resonant-circuit/coil-julia/run.sh
index 08a42b289..6340410ae 100755
--- a/resonant-circuit/coil-julia/run.sh
+++ b/resonant-circuit/coil-julia/run.sh
@@ -4,7 +4,7 @@ set -e -u
 . ../../tools/log.sh
 exec > >(tee --append "$LOGFILE") 2>&1
 
-julia --project=Project.toml -e "using Pkg; Pkg.instantiate();"
+julia --project=Project.toml -e 'using Pkg; Pkg.add("DifferentialEquations"); Pkg.add("PreCICE"); Pkg.instantiate();'
 julia --project=Project.toml coil.jl
 
 close_log
\ No newline at end of file

From cc4dedf866d04e0117368781c4f8121a6700e226 Mon Sep 17 00:00:00 2001
From: marinlauber <marinlauber@gmail.com>
Date: Wed, 6 Aug 2025 10:39:49 +0200
Subject: [PATCH 5/5] rm old Project files

---
 resonant-circuit/capacitor-julia/Project.toml | 3 ---
 resonant-circuit/coil-julia/Project.toml      | 3 ---
 2 files changed, 6 deletions(-)
 delete mode 100644 resonant-circuit/capacitor-julia/Project.toml
 delete mode 100644 resonant-circuit/coil-julia/Project.toml

diff --git a/resonant-circuit/capacitor-julia/Project.toml b/resonant-circuit/capacitor-julia/Project.toml
deleted file mode 100644
index 8a303cd38..000000000
--- a/resonant-circuit/capacitor-julia/Project.toml
+++ /dev/null
@@ -1,3 +0,0 @@
-[deps]
-OrdinaryDiffEq = "1dea7af3-3e70-54e6-95c3-0bf5283fa5ed"
-PreCICE = "57fbd4af-5cc3-4712-aac0-6930e7658184"
diff --git a/resonant-circuit/coil-julia/Project.toml b/resonant-circuit/coil-julia/Project.toml
deleted file mode 100644
index 8a303cd38..000000000
--- a/resonant-circuit/coil-julia/Project.toml
+++ /dev/null
@@ -1,3 +0,0 @@
-[deps]
-OrdinaryDiffEq = "1dea7af3-3e70-54e6-95c3-0bf5283fa5ed"
-PreCICE = "57fbd4af-5cc3-4712-aac0-6930e7658184"