Python中快速的二维插值，采用SciPy正则网格进行离散/不规则评价

I have a regular grid of training values (vectors x and y with respective grids xmesh and ymesh and known values of zmesh) but an scattered / ragged / irregular group of values to be interpolated (vectors xI and yI, where we are interested in zI[0] = f(xI[0],yI[0]) ... zI[N-1] = f(xI[N-1],yI[N-1]). This interpolation will be called millions of times as part of an optimization problem, so performance is too important to simply to use a method that makes the grid and takes the trace.I have a regular grid of training values (vecto