scale turbineX and turbineY to O(1)

topfarm/_topfarm.py

@@ -30,8 +30,10 @@ class TopFarm(object):
             self.boundary_comp = BoundaryComp(boundary, n_wt, boundary_type)
         self.problem = prob = Problem()
         indeps = prob.model.add_subsystem('indeps', IndepVarComp(), promotes=['*'])
-        indeps.add_output('turbineX', turbines[:, 0], units='m')
-        indeps.add_output('turbineY', turbines[:, 1], units='m')
+        min_x, min_y = self.boundary_comp.vertices.min(0)
+        mean_x, mean_y = self.boundary_comp.vertices.mean(0)
+        indeps.add_output('turbineX', turbines[:, 0], units='m', ref=mean_x, ref0=min_x)
+        indeps.add_output('turbineY', turbines[:, 1], units='m', ref=mean_y, ref0=min_y)
         indeps.add_output('boundary', self.boundary_comp.vertices, units='m')
         prob.model.add_subsystem('cost_comp', cost_comp, promotes=['*'])
         prob.driver = ScipyOptimizeDriver()