Piecewise utility function feature

[mgutierrezc]

This feature allows users to input piecewise utility functions in the round_configs/demo.yaml file.

• Documentation for yaml
  

  otree_visual_markets/configs/round_configs/demo.yaml

  Lines 27 to 31 in a4d8d46

  	# if the parameter 'piecewise_utility' is True, the syntax should be a string like this one
  	#"(piece 1, domain for piece 1);(piece 2, domain for piece 2)...". e.g: “(11 + 12*(x+(11.2*y - 0.5*(y**2))), y<11.2);(11 + 12*(x + 0.5*(11.2**2)), y>=11.2)”
  	# else, the syntax is a string with the "function". e.g: "(x ** 0.5) * (y ** 0.5)"
  	piecewise_utility: true
  	utility_function: “(11 + 12*(x+(11.2*y - 0.5*(y**2))), y<11.2);(11 + 12*(x + 0.5*(11.2**2)), y>=11.2)”

• Documentation for models
  

  otree_visual_markets/models.py

  Lines 137 to 143 in a4d8d46

  	def utility_function(self, x, y):
  	"""
  	Evaluates the inputted parameters on a continuous/piecewise function
  	Input: parameter values for x and y (float)
  	Output: value of function after evaluating the values (float)
  	"""