From afc09f9f95a6a0a157f90cf127e57b7288eba6e4 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Miguel=20Mas=C3=B3?= <miguel.maso@upc.edu>
Date: Tue, 25 Aug 2026 15:43:48 +0200
Subject: [PATCH] Added update_displacements! function

---
 .../ComputationalModels.jl                    |  2 ++
 src/ComputationalModels/Drivers.jl            | 30 +++++++++++++++----
 src/Exports.jl                                |  2 ++
 3 files changed, 28 insertions(+), 6 deletions(-)

diff --git a/src/ComputationalModels/ComputationalModels.jl b/src/ComputationalModels/ComputationalModels.jl
index 59484e3a..b27f582f 100644
--- a/src/ComputationalModels/ComputationalModels.jl
+++ b/src/ComputationalModels/ComputationalModels.jl
@@ -69,6 +69,8 @@ export get_spaces
 export get_assemblers
 export get_trial_space
 export get_test_space
+export update_velocity!
+export update_displacements!
 
 include("PostProcessors.jl")
 export PostProcessor
diff --git a/src/ComputationalModels/Drivers.jl b/src/ComputationalModels/Drivers.jl
index 024431ba..16226236 100644
--- a/src/ComputationalModels/Drivers.jl
+++ b/src/ComputationalModels/Drivers.jl
@@ -283,13 +283,31 @@ get_spaces(m::DynamicNonlinearModel) = m.spaces
 get_assemblers(m::DynamicNonlinearModel) = (m.caches[4])
 
 
+"""
+Update the velocity field `vh` based on the current displacement field `xh⁺`
+and the previous displacement `xh⁻` using a midpoint time-stepping scheme.
+The velocity is updated in place.
+"""
+function update_velocity!(vh, xh⁺, xh⁻, Δt)
+  v = get_free_dof_values(vh)
+  v .*= -1.0
+  v .-= (2.0 / Δt) * get_free_dof_values(xh⁻)
+  v .+= (2.0 / Δt) * get_free_dof_values(xh⁺)
+  return vh
+end
+
 
-function update_velocity!(vh, x, x⁻, Δt)
-    vh_ = get_free_dof_values(vh)
-    vh_ .*= -1.0
-    vh_ .-= (2.0 / Δt) .* x⁻
-    vh_ .+= (2.0 / Δt) .* x
-    return vh
+"""
+Update the old displacement field `xh⁻` with the new displacement field `xh⁺`.
+The update is performed in place, modifying `xh⁻` to match both the free dof values
+and the dirichlet dof values of `xh⁺`.
+"""
+function update_displacements!(xh⁻, xh⁺)
+  x = get_free_dof_values(xh⁻)
+  x .= get_free_dof_values(xh⁺)
+  x_dir = get_dirichlet_dof_values(get_fe_space(xh⁻))
+  x_dir .= get_dirichlet_dof_values(get_fe_space(xh⁺))
+  return xh⁻
 end
 
 
diff --git a/src/Exports.jl b/src/Exports.jl
index 406bc8db..ad033c40 100644
--- a/src/Exports.jl
+++ b/src/Exports.jl
@@ -144,6 +144,8 @@ end
 @publish ComputationalModels  dirichlet_preconditioning!
 @publish ComputationalModels  GmshDiscreteModel
 @publish ComputationalModels  updateBC!
+@publish ComputationalModels update_velocity!
+@publish ComputationalModels update_displacements!
 @publish ComputationalModels  PostProcessor
 @publish ComputationalModels  vtk_save
 @publish ComputationalModels  get_pvd