# File lib/gnuplot.rb, line 266
266:   def to_gplot (x = nil, y = nil)
267:     xgrid = x || (0...self.column_size).to_a
268:     ygrid = y || (0...self.row_size).to_a
269:   
270:     f = ""
271:     ygrid.length.times do |j|
272:       y = ygrid[j]
273:       xgrid.length.times do |i|
274:         if ( self[j,i] ) then
275:           f << "#{xgrid[i]} #{y} #{self[j,i]}\n"
276:         end
277:       end
278:     end
279:     
280:     f
281:   end