def sell(self, quantity, seller):
"""Sell the specified quantity
we assume that when we sell, somebody else buys it so the amount issued doesn't change
@param quantity:
@param seller:
@return: the quantity sold and the realised amount
"""
# see how much this seller has
current = network.get_asset_holding(self.simInfo, self, seller)
# scale the quantity if necessary
quantity = min(quantity, current)
# don't allow negative sales
if quantity <= 0.0:
return 0.0, 0.0
newH = current - quantity
# calculate the price
fireSaleFactor = self.get_param('fireSaleFactor', 0.0)
if fireSaleFactor > 0.0:
priceFactor = math.exp(-fireSaleFactor * quantity / self.issued)
newPrice = self.currentPrice * priceFactor
self.set_price(newPrice)
# update the holding
network.set_asset_holding(self.simInfo, self, seller, newH)
self.record_holding_history(seller, newH)
return quantity, quantity * self.currentPrice
def buy(self, quantity, buyer):
"""Create a holding of the specified amount
A holding is an edge in the asset network.
The amount issued is the total created so far
@param buyer:
@param quantity:
@return: the quantity actually bought and the consideration
"""
# don't allow negative purchases
if quantity < 0.0:
return 0.0, 0.0
# see if this buyer already has some
current = network.get_asset_holding(self.simInfo, self, buyer)
newH = current + quantity
network.set_asset_holding(self.simInfo, self, buyer, newH)
self.issued += quantity
self.record_holding_history(buyer, newH)
return quantity, quantity * self.currentPrice
