added test for 2d weighted gap calculation

test/test_mortar_2d_weighted_gap.jl

@@ -0,0 +1,46 @@
+# This file is a part of JuliaFEM.
+# License is MIT: see https://github.com/JuliaFEM/JuliaFEM.jl/blob/master/LICENSE.md
+
+using JuliaFEM.Test
+
+using JuliaFEM.Core: Node, Seg2, update!, calculate_normal_tangential_coordinates!, MortarProblem, assemble, calculate_nodal_vector
+
+macro debug(msg)
+    haskey(ENV, "DEBUG") || return
+    return msg
+end
+
+@testset "calculate mortar matrices and weighted gap vector for 2d model" begin
+    nodes = Node[
+        [1.0, 1.0],
+        [3.0, 1.0],
+        [2.0, 2.0],
+        [4.0, 4.0]]
+    sel = Seg2([1, 2])
+    mel = Seg2([3, 4])
+    update!([sel, mel], "geometry", nodes)
+    calculate_normal_tangential_coordinates!(sel, 0.0)
+    sel["master elements"] = [mel]
+    prob = MortarProblem("displacement", 2)
+    push!(prob, sel)
+    a = assemble(prob, 0.0)
+    C1 = full(a.C1)
+    D = C1[:, [1, 2, 3, 4]]*24
+    M = C1[:, [5, 6, 7, 8]]*24
+    X = calculate_nodal_vector("geometry", 2, [sel, mel], 0.0)
+    @debug begin
+        info("nodal vector")
+        dump(round(full(X), 3))
+    end
+    g = -C1*X
+    g = full(g)
+    @debug begin
+        dump(round(D, 3))
+        dump(round(M, 3))
+        dump(round(g, 3))
+    end
+    I = eye(2)
+    @test isapprox(D, [2*I 4*I; 4*I 14*I])
+    @test isapprox(-M, [5*I 1*I; 13*I 5*I])
+    @test isapprox(g, 1/6*[0, 2, 0, 7])
+end