red through orange, yellow, green,blue to violet colormap
cmap=rainbowcolormap(n)
:n integer >= 3, the colormap size. : :cmap matrix with 3 columns [R,G,B]. :
rainbowcolormap computes a colormap with n colors varying from red through orange, yellow, green,blue to violet.
f = `scf`_();
`plot3d1`_();
f.color_map = rainbowcolormap(32);