Wave equation staggered grid tests (Mixed BC, Periodic BC) produce incorrect results #508
Description
Description
The wave equation staggered grid tests for Mixed BC and Periodic BC are producing results that are orders of magnitude off from expected values.
Mixed BC test (line 45-46):
maximum(sol[1:128, 1] .- sol[1:128, test_ind])= 0.808 (expected < 0.015625)maximum(sol[1:128, 1] .- sol[1:128, 2test_ind])= 1.615 (expected < 0.15625)
Periodic BC test (line 129-130):
maximum(sol[1:128, 1] .- sol[1:128, test_ind])= 0.797 (expected < 0.015625)maximum(sol[1:128, 1] .- sol[1:128, 2test_ind])= 1.599 (expected < 0.15625)
The Neumann BC test continues to pass.
These tests have been marked as @test_broken in PR #507 to unblock CI, but the underlying issue needs investigation. The errors are too large to be a tolerance issue - something appears to be fundamentally wrong with the Mixed BC and Periodic BC discretization for the staggered wave equation.
Reproduction
Run the Wave_Eq_Staggered test group:
using Pkg; Pkg.test("MethodOfLines", test_args=["Wave_Eq_Staggered"])