AJRM - 2011-12-04

I need to generate graphs that pass through specified points (x0, y0), (x1, y1). It would also be nice to
have specified slopes at various points too (x = z0, m = m0), (x = z1, m = m1), …

The pgfplotstream comes close to this functionality with the curveto handler. It allows you to specify points. However, I haven't been able to get it to produce beautiful rounded graphs, even after tweaking the tension parameter. The graphs are always somewhat angular or lopsided looking. It also doesn't directly to slopes.

Does anyone have an idea for a convenient way to do this?