## Plotting 3D Surfaces ## Surface plotting creates a 3D surface plot of a given matrix `z`. Entries of `z` are used as height values. It is also possible to specify `x` and `y` locations corresponding to each point in `z` . If a terminal with interactive capabilities is being used by `Gnuplot` backend (like `x11` or `wxt` or `qt`), then rotating, zooming is also possible. ### gnuplot.splot(z) ### Plot surface ` z ` in 3D. ```lua x = torch.linspace(-1,1) xx = torch.Tensor(x:size(1),x:size(1)):zero():addr(1,x,x) xx = xx*math.pi*6 gnuplot.splot(torch.sin(xx)) ```  It is also possible to specify the `x` and `y` locations of each point in `z` by `gnuplot.splot(x,y,z)`. In this `x` and `y` has to be the same shape as `z`. One can also display multiple surfaces at a time. ```lua x = torch.linspace(-1,1) xx = torch.Tensor(x:size(1),x:size(1)):zero():addr(1,x,x) xx = xx*math.pi*2 gnuplot.splot({torch.sin(xx)},{torch.sin(xx)+2}) ```