Plotting

Visualization is a package extension (MultiGridBarrierPyPlotExt): it loads automatically once both MultiGridBarrier and PyPlot are imported, and its methods extend PyPlot.plot and PyPlot.savefig — so plot is one function whether you hand it matplotlib arrays or MultiGridBarrier solutions. Without PyPlot, the solver core has no Python dependency at all.

What plot does

plot(sol::MGBSOL, k=1; kwargs...)          # k-th solution component on sol.geometry
plot(sol::ParabolicSOL, k=1; kwargs...)    # HTML5 animation of a time-dependent solve
plot(M::Geometry, z::Vector; kwargs...)    # a nodal vector on a geometry
plot(M::Geometry, ts, U::Matrix; ...)      # animate the columns of U at times ts

The rendering is chosen by the geometry:

• 1D (fem1d, spectral1d): line plot. Spectral solutions are sampled through interpolate; choose the points with x = -1:0.01:1.
• 2D FEM (fem2d_P1, fem2d_P2, fem2d): triangulated surface plot (plot_trisurf) on the mesh structure.
• 2D spectral (spectral2d): 3D surface plot on an evaluation grid (x = -1:0.01:1, y = -1:0.01:1).
• 3D FEM (fem3d) and embedded manifolds (fem2d/fem1d with ambient = Val(3)): PyVista renders — volume + isosurfaces + slices for volumes, colored quad meshes for surfaces, tubes for curves. These return an MGB3DFigure (PNG bytes) that displays inline in Jupyter/Documenter and saves with savefig(fig, "out.png").

Remaining keyword arguments pass through to the underlying PyPlot/PyVista calls.

using MultiGridBarrier, PyPlot
sol = mgb_solve(assemble(amg(subdivide(fem2d_P2(), 3)); p = 1.0); verbose = false)
plot(sol)

Animations

Time-dependent solutions animate into an HTML5anim — an HTML5 <video> that embeds inline in Jupyter, Pluto, and Documenter:

sol = parabolic_solve(amg(subdivide(fem2d_P1(), 3)); h = 0.1)
plot(sol)                       # matplotlib.animation (1D/2D)
plot(sol.geometry, ts, U)       # or animate any matrix of frames directly

The animation advances at a fixed frame rate (frame_time seconds per video frame); for irregular ts, each video frame shows the latest data frame with timestamp ≤ the current video time. In 1D/2D the video is produced by matplotlib.animation (embed_limit caps the embedded size in megabytes, and the printer callback receives the Matplotlib animation object, e.g. to anim.save("out.mp4")). In 3D, PyVista frames are encoded by ffmpeg.

Result types

MGB3DFigure

HTML5anim