Display multiple graphs in iRuby

Question

I'm trying to display multiple graphs, and each graph have two subplots, with horizontal layout, in one output in iRuby, running on google Colaboratory.

I first used Nyaplot, but it doesn't work. I don't know why, but it simply gave me no response.

This is my source to check it works:

require 'nyaplot'

plot = Nyaplot::Plot.new
plot.add(:bar, ['Persian', 'Maine Coon', 'American Shorthair'], [10,20,30])
plot.x_label("Species")
plot.y_label("Number")
p = Nyaplot::Frame.new
p.add(plot)
p.show

and this is output :

#<CZTop::Socket::PUB:0x5609e3406f80 last_endpoint="tcp://127.0.0.1:42375">

and nothing more.

So I changed to Matplotlib :: Pyplot, and it worked fine. (Except it was too slow when I try to use subplot.) But when I tried to display multiple graph in one cell, every output was merged, so I can't use it.

Tested this example code:

def a
    plt = Matplotlib::pyplot

    xs = [*1..100]

    ys = xs.map {|x| Math.sin(Math::PI * x / 20.0) + 0.1 * (rand - 0.5) }
    ys2 = xs.map {|x| Math.cos(Math::PI * x / 20.0) + 0.1 * (rand - 0.5) }

    plt.subplot(2,1,1)
    plt.plot(xs, ys, "r", label: "Hello")
    plt.title("a")
    plt.plot(xs, ys2, "b", label: "GoodBye")
    plt.legend
    plt.subplot(2,1,2)
    plt.plot(ys, xs, "r", label: "hello?")
    plt.plot(ys2, xs, "b", label: "goodbye?")
    plt.title("b")
    plt.legend

    plt.show
end

a()
a()
a()

and got this image

So I changed to daru-view, but it can't display multiple graph in one output, with simply call show_in_iruby more than one time. Additionally, I need something like subplot in matplotlib, but I cannot find some with horizontal layout.

with this code:

Daru::View.plotting_library = :googlecharts
idx = Daru::Index.new ['a', 'b', 'c']
df_1 = Daru::DataFrame.new([[1,2,3], [1,2,3], [1,3,5]])
df_1.vectors = idx
idx2 = Daru::Index.new ['a', 'b', 'c']
df_2 = Daru::DataFrame.new([[1,2,3], [1,2,3], [1,2,3]])
df_2.vectors = idx2

options = {title: "name", colors: ["red", "blue"]}
plt1 = Daru::View::Plot.new(df_1, options)
plt2 = Daru::View::Plot.new(df_2, options)
plt1.show_in_iruby
plt2.show_in_iruby

got image like this

What should I do to display multiple graph in one output?