Add julia example in resonant circuit

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
 

resonant-circuit/capacitor-julia/capacitor.jl

@@ -0,0 +1,82 @@
+using PreCICE
+using DifferentialEquations
+
+# 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, zeros((1,dimensions)))
+
+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()
+        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
+    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
+    end
+    # Stop coupling
+    PreCICE.finalize()
+end

resonant-circuit/capacitor-julia/run.sh

@@ -0,0 +1,10 @@
+#!/usr/bin/env bash
+set -e -u
+
+. ../../tools/log.sh
+exec > >(tee --append "$LOGFILE") 2>&1
+
+julia --project=Project.toml -e 'using Pkg; Pkg.add("DifferentialEquations"); Pkg.add("PreCICE"); Pkg.instantiate();'
+julia --project=Project.toml capacitor.jl
+
+close_log

resonant-circuit/coil-julia/coil.jl

@@ -0,0 +1,85 @@
+using PreCICE
+using DifferentialEquations
+
+# 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, zeros((1,dimensions)))
+
+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()
+        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
+    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
+    end
+    # Stop coupling
+    PreCICE.finalize()
+end

resonant-circuit/coil-julia/run.sh

@@ -0,0 +1,10 @@
+#!/usr/bin/env bash
+set -e -u
+
+. ../../tools/log.sh
+exec > >(tee --append "$LOGFILE") 2>&1
+
+julia --project=Project.toml -e 'using Pkg; Pkg.add("DifferentialEquations"); Pkg.add("PreCICE"); Pkg.instantiate();'
+julia --project=Project.toml coil.jl
+
+close_log