add an Euler problem showing a similar issue at the boundary

to the shallow water example. Can be seen when limiter tolerance is changed
from 1 to 1e-10

pydemo/euler/euler.py

@@ -114,3 +114,12 @@ def radialSod3(dim,gamma):
                           CompressibleEuler(dim,gamma).toCons([0.125,0,0,0.1])),\
            [-0.5, -0.5], [0.5, 0.5], [20, 20], 0.5,\
            "radialSod3"
+
+def leVeque(dim,gamma):
+    space = Space(dim,dim+2)
+    x = SpatialCoordinate(space.cell())
+    initial = conditional(abs(x[0]-0.15)<0.05,1.2,1)
+    return CompressibleEulerDirichlet(dim,gamma),\
+           as_vector( [initial,0,0,initial] ),\
+           [0, 0], [1, 0.25], [64, 16], 0.7,\
+           "leVeque1D"

pydemo/euler/parameter

@@ -3,7 +3,7 @@
 # 0 = only dg solution | 1 = only reconstruction | 2 = both
 femdg.limiter.admissiblefunctions: 1
 # tolerance for shock indicator
-femdg.limiter.tolerance: 1
+femdg.limiter.tolerance: 1 # 1e-10
 # threshold for avoiding over-excessive limitation
 femdg.limiter.limiteps: 1e-8
 

pydemo/euler/shock_tube.py

@@ -11,7 +11,8 @@ gamma = 1.4
 dim = 2
 
 from euler import sod as problem
-#from euler import radialSod3 as problem
+# from euler import leVeque as problem
+# from euler import radialSod3 as problem
 
 Model, initial, x0,x1,N, endTime, name = problem(dim,gamma)
 

pydemo/shallowWater/parameter

@@ -3,9 +3,9 @@
 # 0 = only dg solution | 1 = only reconstruction | 2 = both
 femdg.limiter.admissiblefunctions: 1
 # tolerance for shock indicator
-femdg.limiter.tolerance: 1
+femdg.limiter.tolerance: 1 # 1e-10
 # threshold for avoiding over-excessive limitation
-femdg.limiter.limiteps: 1e-8
+femdg.limiter.limiteps: 1e-15
 
 # GENERAL
 #--------

pydemo/shallowWater/shallowwater.py

@@ -33,8 +33,8 @@ def ShallowWater(topography,g):
             return (hL - hR)/(0.5*(hL + hR))
         def S_ns(t,x,U,DU): # or S_s for a stiff source
             return as_vector( [0, *(-U[0]*g*grad(topography(x))) ])
-        boundary = {range(1,5): lambda t,x,u,n: Model.F_c(t,x,u)*n}
-        # boundary = {range(1,5): lambda t,x,u: u}
+        # boundary = {range(1,5): lambda t,x,u,n: Model.F_c(t,x,u)*n}
+        boundary = {range(1,5): lambda t,x,u: u}
     return Model
 
 # example 5.1 and 7.1 from