From bad2feb0320c280325afbe9c438f114a19f7f756 Mon Sep 17 00:00:00 2001
From: Andreas Dutzler <a.dutzler@gmail.com>
Date: Sat, 30 Mar 2024 22:52:01 +0100
Subject: [PATCH 1/2] Fix `FieldContainer.evaluate.strain()` for custom
 strain-stretch

---
 docs/tutorial/examples/extut03_building_blocks.py | 9 ++++++++-
 src/felupe/field/_evaluate.py                     | 4 +++-
 2 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/docs/tutorial/examples/extut03_building_blocks.py b/docs/tutorial/examples/extut03_building_blocks.py
index 50c84084..14673308 100644
--- a/docs/tutorial/examples/extut03_building_blocks.py
+++ b/docs/tutorial/examples/extut03_building_blocks.py
@@ -25,8 +25,9 @@
 """
 # sphinx_gallery_thumbnail_number = -1
 import felupe as fem
+import numpy as np
 
-mesh = fem.Cube(n=9)
+mesh = fem.Cube(n=6)
 element = fem.Hexahedron()
 quadrature = fem.GaussLegendre(order=1, dim=3)
 
@@ -104,6 +105,12 @@
 # identity matrix is added to the gradient of the field.
 F = field.extract(grad=True, sym=False, add_identity=True)
 
+# %%
+# Methods to evaluate the deformation gradient as well as strain measures are
+# provided in :class:`FieldContainer.evaluate <felupe.field.EvaluateFieldContainer>`.
+log_strain = field.evaluate.strain(fun=lambda stretch: np.log(stretch), tensor=True)
+principal_stretches = field.evaluate.strain(fun=lambda stretch: stretch, tensor=False)
+
 # %%
 # Constitution
 # ~~~~~~~~~~~~
diff --git a/src/felupe/field/_evaluate.py b/src/felupe/field/_evaluate.py
index 31071d94..984af36d 100644
--- a/src/felupe/field/_evaluate.py
+++ b/src/felupe/field/_evaluate.py
@@ -91,7 +91,9 @@ def strain(self, fun=strain_stretch_1d, tensor=True, asvoigt=False, n=0, **kwarg
         math.strain : Compute a Lagrangian strain tensor.
         math.strain_stretch_1d : Compute the Seth-Hill strains.
         """
-        return strain(self.field, tensor=tensor, asvoigt=asvoigt, n=0, **kwargs)
+        return strain(
+            self.field, fun=fun, tensor=tensor, asvoigt=asvoigt, n=0, **kwargs
+        )
 
     def log_strain(self, tensor=True, asvoigt=False, n=0):
         r"""Return the logarithmic Lagrangian strain tensor or its principal values.

From 69edfc93934c17f88c168aa0e3ddeb65cdd8a4d8 Mon Sep 17 00:00:00 2001
From: Andreas Dutzler <a.dutzler@gmail.com>
Date: Sat, 30 Mar 2024 22:53:32 +0100
Subject: [PATCH 2/2] Set version tag to 8.2.1

---
 CHANGELOG.md            | 5 +++++
 src/felupe/__about__.py | 2 +-
 2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 63388dfa..5b48a602 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -3,6 +3,11 @@ All notable changes to this project will be documented in this file. The format
 
 ## [Unreleased]
 
+## [8.2.1] - 2024-03-30
+
+### Fixed
+- Fix `FieldContainer.evaluate.strain(fun=lambda stretch: stretch)` for custom strain-stretch callables. The `fun`-argument was previously ignored.
+
 ## [8.2.0] - 2024-03-25
 
 ### Added
diff --git a/src/felupe/__about__.py b/src/felupe/__about__.py
index c0968f8f..1f1024b1 100644
--- a/src/felupe/__about__.py
+++ b/src/felupe/__about__.py
@@ -1 +1 @@
-__version__ = "8.3.0-dev"
+__version__ = "8.2.1"