def _calc(self):
if self.portfolio.value >= (1 + self.up_threshold) * self.get_required_portfolio():
new_amount = pmt(self.get_rate(), self.get_life_expectancy(), self.portfolio.value)
new_rate = new_amount / self.portfolio.value
self.current_rate += (new_rate - self.current_rate) * self.upward_rate_adjustment
self.current_rate = min(self.current_rate, self.ceiling_rate)
if self.portfolio.value < (1 + self.down_threshold) * self.get_required_portfolio():
new_amount = pmt(self.get_rate(), self.get_life_expectancy(), self.portfolio.value)
new_rate = new_amount / self.portfolio.value
self.current_rate -= (self.current_rate - new_rate) * self.downward_rate_adjustment
self.current_rate = max(self.current_rate, self.floor_rate)
amount = self.current_rate * self.portfolio.value
self.current_age += 1
return amount
def harvest(self):
amount = yield
while True:
amount_left = amount
if self.portfolio.bonds_pct > self.target_bonds:
bonds_excess = (self.portfolio.bonds_pct - self.target_bonds) * self.portfolio.value
bonds_excess = round(bonds_excess)
bonds_to_sell = min(amount, bonds_excess)
self.portfolio.sell_bonds(bonds_to_sell)
amount_left -= bonds_to_sell
else:
bonds_deficit = -(self.portfolio.bonds_pct - self.target_bonds) * self.portfolio.value
bonds_deficit = round(bonds_deficit)
self.portfolio.sell_stocks(bonds_deficit)
self.portfolio.buy_bonds(bonds_deficit)
bonds_to_sell = amount_left * self.target_bonds
stocks_to_sell = amount_left - bonds_to_sell
self.portfolio.sell_bonds(bonds_to_sell)
self.portfolio.sell_stocks(stocks_to_sell)
pmt_amount = pmt(self.discount_rate, self.final_age - self.current_age, self.portfolio.value)
if amount < pmt_amount and amount >= self.initial_withdrawal:
harvest = pmt_amount - amount
self.portfolio.buy_bonds(harvest)
amount = yield self.portfolio.empty_cash()
def harvest(self):
amount = yield
while True:
amount_left = amount
if self.portfolio.bonds_pct > self.target_bonds:
bonds_excess = (self.portfolio.bonds_pct -
self.target_bonds) * self.portfolio.value
bonds_excess = round(bonds_excess)
bonds_to_sell = min(amount, bonds_excess)
self.portfolio.sell_bonds(bonds_to_sell)
amount_left -= bonds_to_sell
else:
bonds_deficit = -(self.portfolio.bonds_pct -
self.target_bonds) * self.portfolio.value
bonds_deficit = round(bonds_deficit)
self.portfolio.sell_stocks(bonds_deficit)
self.portfolio.buy_bonds(bonds_deficit)
bonds_to_sell = amount_left * self.target_bonds
stocks_to_sell = amount_left - bonds_to_sell
self.portfolio.sell_bonds(bonds_to_sell)
self.portfolio.sell_stocks(stocks_to_sell)
pmt_amount = pmt(self.discount_rate,
self.final_age - self.current_age,
self.portfolio.value)
if amount < pmt_amount and amount >= self.initial_withdrawal:
harvest = pmt_amount - amount
self.portfolio.buy_bonds(harvest)
amount = yield self.portfolio.empty_cash()
def _calc(self):
rate = (self.portfolio.stocks_pct * self.stock_growth_rate
+ self.portfolio.bonds_pct * self.bond_growth_rate)
amt = pmt(rate, self.years_left, self.portfolio.value)
# max out at 20% of the current portfolio...this allows it to run
# "indefinitely"
return min(amt, self.portfolio.value / 5)
def _calc(self):
amount = pmt(self.rate, self.final_age - self.current_age, self.portfolio.value)
desired_pmt = self.desired_payment * self.cumulative_inflation
desired_value = pv(float(self.rate), self.final_age - self.current_age, float(-desired_pmt), when='begin')
desired_value = Decimal(desired_value)
tilt = (self.portfolio.value / desired_value) ** self.tilt
return amount * tilt
def _calc(self):
# Siegel & Waring suggest the discount rate should be
# "TIPS interest rate (present-value-weighted average interest rate across the TIPS
# ladder)" at the start of each year.
# Currently, we don't support changing the discount_rate every year and use a constant rate
rate = self.discount_rate
# Siegel & Waring suggest using the average of 120 (the maximum known human life span) and
# life expectancy based on current age according to the Social Security tables.
years_left = average([ARVA.MAX_AGE, get_life_expectancy(self.current_age)])
return pmt(rate, years_left, self.portfolio.value)
def _calc(self):
# shortcut if the portfolio is 0...some of the math
# below doesn't like 0s.
if self.portfolio.value == 0:
return Decimal(0)
amount = pmt(self.rate, self.final_age - self.current_age, self.portfolio.value)
desired_pmt = self.desired_payment * self.cumulative_inflation
desired_value = pv(float(self.rate), self.final_age - self.current_age, float(-desired_pmt), when='begin')
desired_value = Decimal(desired_value)
tilt = (self.portfolio.value / desired_value) ** self.tilt
return amount * tilt
def _calc(self):
p_v = pmt(self.discount_rate, self.final_age - self.current_age, self.portfolio.value)
if p_v < self.current_withdrawal:
self.retrenchments.append((self.current_age, self.current_withdrawal, p_v))
if self.only_down:
if p_v < self.current_withdrawal: self.current_withdrawal = p_v
else:
self.current_withdrawal = p_v
return self.current_withdrawal
def _calc(self):
if self.portfolio.value >= (
1 + self.up_threshold) * self.get_required_portfolio():
new_amount = pmt(self.get_rate(), self.get_life_expectancy(),
self.portfolio.value)
new_rate = new_amount / self.portfolio.value
self.current_rate += (
new_rate - self.current_rate) * self.upward_rate_adjustment
self.current_rate = min(self.current_rate, self.ceiling_rate)
if self.portfolio.value < (
1 + self.down_threshold) * self.get_required_portfolio():
new_amount = pmt(self.get_rate(), self.get_life_expectancy(),
self.portfolio.value)
new_rate = new_amount / self.portfolio.value
self.current_rate -= (self.current_rate -
new_rate) * self.downward_rate_adjustment
self.current_rate = max(self.current_rate, self.floor_rate)
amount = self.current_rate * self.portfolio.value
self.current_age += 1
return amount
def _calc(self):
# Siegel & Waring suggest the discount rate should be
# "TIPS interest rate (present-value-weighted average interest rate across the TIPS
# ladder)" at the start of each year.
# Currently, we don't support changing the discount_rate every year and use a constant rate
rate = self.discount_rate
# Siegel & Waring suggest using the average of 120 (the maximum known human life span) and
# life expectancy based on current age according to the Social Security tables.
years_left = average(
[ARVA.MAX_AGE, get_life_expectancy(self.current_age)])
return pmt(rate, years_left, self.portfolio.value)
def _calc(self):
p_v = pmt(self.discount_rate, self.final_age - self.current_age,
self.portfolio.value)
if p_v < self.current_withdrawal:
self.retrenchments.append(
(self.current_age, self.current_withdrawal, p_v))
if self.only_down:
if p_v < self.current_withdrawal: self.current_withdrawal = p_v
else:
self.current_withdrawal = p_v
return self.current_withdrawal
def _calc(self):
p_v = pmt(self.discount_rate, self.final_age - self.current_age, self.portfolio.value)
# React immediately to downward market conditions.
if p_v < self.current_withdrawal:
self.current_withdrawal = p_v
# Only do the harvest if we aren't under water from where we started
elif p_v < self.initial_withdrawal:
self.current_withdrawal = p_v
else:
excess_funds = p_v - self.current_withdrawal
lifestyle_creep = excess_funds * self.lifestyle_pct
self.current_withdrawal = min(lifestyle_creep + self.current_withdrawal, self.max_withdrawal)
return self.current_withdrawal
def _calc(self):
# shortcut if the portfolio is 0...some of the math
# below doesn't like 0s.
if self.portfolio.value == 0:
return Decimal(0)
amount = pmt(self.rate, self.final_age - self.current_age,
self.portfolio.value)
desired_pmt = self.desired_payment * self.cumulative_inflation
desired_value = pv(float(self.rate),
self.final_age - self.current_age,
float(-desired_pmt),
when='begin')
desired_value = Decimal(desired_value)
tilt = (self.portfolio.value / desired_value)**self.tilt
return amount * tilt
def _calc(self):
p_v = pmt(self.discount_rate, self.final_age - self.current_age,
self.portfolio.value)
# React immediately to downward market conditions.
if p_v < self.current_withdrawal:
self.current_withdrawal = p_v
# Only do the harvest if we aren't under water from where we started
elif p_v < self.initial_withdrawal:
self.current_withdrawal = p_v
else:
excess_funds = p_v - self.current_withdrawal
lifestyle_creep = excess_funds * self.lifestyle_pct
self.current_withdrawal = min(
lifestyle_creep + self.current_withdrawal, self.max_withdrawal)
return self.current_withdrawal
def __init__(self, portfolio, harvest_strategy,
current_age=65,
final_age=110,
discount_rate=.08,
only_down=True):
super().__init__(portfolio, harvest_strategy)
self.discount_rate = discount_rate
self.final_age = final_age
self.current_age = current_age
# Do we only "retrench" or do we also increase the withdrawals?
# Setting this to true means using PMT directly.
self.only_down = only_down
self.current_withdrawal = pmt(self.discount_rate, self.final_age - self.current_age, self.portfolio.value)
self.retrenchments = []
def __init__(self, portfolio,
current_age=65,
final_age=110,
discount_rate=.06,
lifestyle_pct=.25,
lifestyle_cap=2):
strategy = self.harvest()
strategy.send(None)
super().__init__(portfolio, strategy)
self.discount_rate = discount_rate
self.final_age = final_age
self.current_age = current_age
self.current_withdrawal = pmt(self.discount_rate, self.final_age - self.current_age, self.portfolio.value)
self.initial_withdrawal = self.current_withdrawal
self.lifestyle_pct = Decimal(lifestyle_pct)
self.target_bonds = portfolio.bonds_pct
self.max_withdrawal = self.initial_withdrawal * Decimal(lifestyle_cap)
def __init__(self,
portfolio,
harvest_strategy,
current_age=65,
final_age=110,
discount_rate=.08,
only_down=True):
super().__init__(portfolio, harvest_strategy)
self.discount_rate = discount_rate
self.final_age = final_age
self.current_age = current_age
# Do we only "retrench" or do we also increase the withdrawals?
# Setting this to true means using PMT directly.
self.only_down = only_down
self.current_withdrawal = pmt(self.discount_rate,
self.final_age - self.current_age,
self.portfolio.value)
self.retrenchments = []
def __init__(self,
portfolio,
current_age=65,
final_age=110,
discount_rate=.06,
lifestyle_pct=.25,
lifestyle_cap=2):
strategy = self.harvest()
strategy.send(None)
super().__init__(portfolio, strategy)
self.discount_rate = discount_rate
self.final_age = final_age
self.current_age = current_age
self.current_withdrawal = pmt(self.discount_rate,
self.final_age - self.current_age,
self.portfolio.value)
self.initial_withdrawal = self.current_withdrawal
self.lifestyle_pct = Decimal(lifestyle_pct)
self.target_bonds = portfolio.bonds_pct
self.max_withdrawal = self.initial_withdrawal * Decimal(lifestyle_cap)