• David Deepwell's avatar
    Update map_iwave case to use new diagnostics · e6b803fd
    David Deepwell authored
    This case has uncovered that the BPE calculation returns
    incorrect values when a Chebyshev grid is used on a field scale.
    The BPE calculation uses the quadrature weights as the volumes
    of each cell. This is true when the grid is regular, but incorrect
    for Chebyshev grids.
    To first approximation the Cheb quadrature weights are close to
    the volumes of the cells. This leads to the BPE calculation
    being accurate to 8 significant figures. 8 sig figs is not enough
    on fields scales since the magnitude of the PE can be very, very
    large. The difference of the BPE from the PE can thus be smaller
    than these 8 sig figs.