streamplot for dxSavePlot=0

[henry2004y]

In BATSRUS,

• dxSavePlot = -1 => unstructured grid, cuts are saved point-wise with no grid information
• dxSavePlot = 0 => structured grid at the finest cell level. For AMR 2D cuts, this will introduce many duplicate points such that the output file size is about 3 times larger than the unstructured equivalent.

In our plotting routines, it takes significantly longer time (~20x for ~100 MB data) to reconstruct the mesh given unstructured outputs. Streamline plotting is working, though.

Streamline plotting for AMR structured grid is not working.

[henry2004y]

Maybe quiver is a better solution here. Now I've added a wrapper over PyPlot.quiver and it works for AMR structured grid.

Check bd4e15ac1d3b214ee1