In [1]:
require 'gnuplotrb'
include GnuplotRB
include Math
double_pi = PI * 2
plot3d = Splot.new(
'cos(x)*cos(y)',
xrange: -double_pi..double_pi,
yrange: -double_pi..double_pi,
style: 'function linespoints',
hidden3d: true,
isosample: 30,
term: ['pngcairo', size: [600, 600]]
)
Out[1]:
Plot surface from given points¶
Gnuplot also may plot surfaces given as data arrays. Options 'dgrid3d' is necessary here to make surface smooth. It takes field size (some kind of 'isosamples') and interpolation options.
In [2]:
def z_function(x, y)
arg = x ** 2 + y ** 2
cos(arg) * exp(-arg/5.0)
end
initial = (-PI..PI).step(0.05).to_a
x = initial * initial.size
y = initial.map { |el| [el] * initial.size }.flatten
z = x.map.with_index { |val, index| z_function(val, y[index]) }
plot3d_points = Splot.new(
[[x,y,z], title: 'Surface from points'],
dgrid3d: [100, qnorm: 8],
style: 'data lines',
hidden3d: true,
xrange: -PI..PI,
yrange: -PI..PI,
term: ['pngcairo', size: [600, 600]]
)
Out[2]:
