From 170c01f9eb0a4f0ea2c46997d5a9b0e329467709 Mon Sep 17 00:00:00 2001
From: Jukka Aho <ahojukka5@gmail.com>
Date: Sun, 13 Oct 2019 12:24:27 +0300
Subject: [PATCH] Give meaningful error message when assembling continuum
 elasticity problem fails

Sometimes user may have the wrong kind of elements in element set when
assembling 3d continuum problem. This could happen for example in
situations, where mesher is giving also segment elements. They may have
some use in certain situations, but currently we don't support them.
When assembly is failing for this reasons, we give a meaningful error
message:

[ Info: It looks that you are trying to assemble elements of type Seg3
to 3d continuum problem. However, they are not supported yet. To filter
out elements from a element set, try `filter(element->!isa(element,
Element{Seg3}), elements)`
ERROR: LoadError: Tried to assemble unsupported elements of type Seg3 to
3d continuum problem.

This commit closes issue #211.
---
 src/problems_elasticity.jl                       | 16 ++++++++++++++++
 .../test_problems_elasticity_assemble_3d_seg3.jl | 12 ++++++++++++
 2 files changed, 28 insertions(+)
 create mode 100644 test/test_problems_elasticity_assemble_3d_seg3.jl

diff --git a/src/problems_elasticity.jl b/src/problems_elasticity.jl
index 13e680f..62a675a 100644
--- a/src/problems_elasticity.jl
+++ b/src/problems_elasticity.jl
@@ -394,6 +394,22 @@ function assemble!(assembly::Assembly,
     end
 end
 
+"""
+    assemble!(assembly, problem, elements, time, ::Type{Val{:continuum}})
+
+Assemble all other elements for continuum elasticity problems. Basically,
+do nothing.
+"""
+function assemble!(assembly::Assembly,
+                   problem::Problem{Elasticity},
+                   elements::Vector{Element{El}},
+                   time, ::Type{Val{:continuum}}) where El
+    @info("It looks that you are trying to assemble elements of type $El to 3d continuum "*
+          "problem. However, they are not supported yet. To filter out elements from a "*
+          "element set, try `filter(element->!isa(element, Element{$El}), elements)`")
+    error("Tried to assemble unsupported elements of type $El to 3d continuum problem.")
+end
+
 """ Return strain tensor. """
 function get_strain_tensor(problem, element, ip, time)
     gradu = element("displacement", ip, time, Val{:Grad})
diff --git a/test/test_problems_elasticity_assemble_3d_seg3.jl b/test/test_problems_elasticity_assemble_3d_seg3.jl
new file mode 100644
index 0000000..b277ea6
--- /dev/null
+++ b/test/test_problems_elasticity_assemble_3d_seg3.jl
@@ -0,0 +1,12 @@
+# This file is a part of JuliaFEM.
+# License is MIT: see https://github.com/JuliaFEM/JuliaFEM.jl/blob/master/LICENSE.md
+
+using JuliaFEM, Test
+
+# Test that if 3d continuum problem have some elements we don't know how to
+# deal with, raise error with clear message
+
+elements = [Element(Seg3, (1, 2, 3))]
+problem = Problem(Elasticity, "test seg3", 3)
+add_elements!(problem, elements)
+@test_throws ErrorException assemble!(problem, 0.0)