fix plotting 1d function (#2271)

Author: JoshuaLampert

src/visualization/recipes_plots.jl

@@ -175,7 +175,7 @@ end
 # We need this recipe in addition to the one above to avoid method ambiguities.
 RecipesBase.@recipe function f(func::Function, semi::AbstractSemidiscretization;
                                solution_variables = nothing)
-    n_variables = length(func(0.0, semi.equations))
+    n_variables = length(func(SVector(0.0), semi.equations))
     variable_names = SVector(["func[$i]" for i in 1:n_variables]...)
     if ndims(semi) == 1
         return PlotData1D(func, semi; solution_variables = cons2cons, variable_names)
@@ -210,7 +210,7 @@ RecipesBase.@recipe function f(func::Function,
                                solution_variables = nothing,
                                nvisnodes = nothing, slice = :xy,
                                point = (0.0, 0.0, 0.0), curve = nothing)
-    n_variables = length(func(0.0, semi.equations))
+    n_variables = length(func(SVector(0.0), semi.equations))
     variable_names = SVector(["func[$i]" for i in 1:n_variables]...)
     if ndims(semi) == 1
         return PlotData1D(func, semi; solution_variables = cons2cons, nvisnodes, slice,

src/visualization/types.jl

@@ -529,7 +529,8 @@ plotting. This can be changed by passing an appropriate conversion function to
 
 Alternatively, you can also pass a function `u` with signature `u(x, equations)`
 returning a vector. In this case, the `solution_variables` are ignored. This is useful,
-e.g., to visualize an analytical solution.
+e.g., to visualize an analytical solution. The spatial variable `x` is a vector with one
+element.
 
 `nvisnodes` specifies the number of visualization nodes to be used. If it is `nothing`,
 twice the number of solution DG nodes are used for visualization, and if set to `0`,
@@ -635,7 +636,7 @@ function PlotData1D(u, mesh::TreeMesh, equations, solver, cache;
                       orientation_x)
 end
 
-# unwrap u if it is VectorOfArray 
+# unwrap u if it is VectorOfArray
 PlotData1D(u::VectorOfArray, mesh, equations, dg::DGMulti{1}, cache; kwargs...) = PlotData1D(parent(u),
                                                                                              mesh,
                                                                                              equations,