principalPayment¶
Evaluates the payment on the principal for a specified period.
Synopsis¶
principalPayment (rate, period, nPeriods, presentValue, futureValue, when)
Required Arguments¶
- float
rate
(Input) - Interest rate.
- int
period
(Input) - Payment period.
- int
nPeriods
(Input) - Total number of periods.
- float
presentValue
(Input) - The current value of a stream of future payments, after discounting the payments using some interest rate.
- float
futureValue
(Input) - The value, at some time in the future, of a current amount and a stream of payments.
- int
when
(Input) - Time in each period when the payment is made, either
AT_END_OF_PERIOD
orAT_BEGINNING_OF_PERIOD
. For a more detailed discussion onwhen
see the Usage Notes section of this chapter.
Return Value¶
The payment on the principal for a given period. If no result can be computed, NaN is returned.
Description¶
Function principalPayment
computes the payment on the principal for a
given period.
It is computed using the following:
paymenti−interesti
where paymenti is computed from payment
for the i-th
period, interesti is calculated from interestPayment
for the
i-th period.
Example¶
In this example, principalPayment
computes the principal paid for the
first year on a 30-year $100,000 loan with an annual interest rate of 8%.
The payment is made at the end of each year.
from __future__ import print_function
from numpy import *
from pyimsl.math.principalPayment import principalPayment, AT_END_OF_PERIOD
rate = 0.08
period = 1
n_periods = 30
present_value = 100000.00
future_value = 0.0
when = AT_END_OF_PERIOD
principal = principalPayment(rate, period, n_periods,
present_value, future_value, when)
print("The payment on the principal for the first year of ")
print("the $100,000 loan is $%.2f." % (principal))
Output¶
The payment on the principal for the first year of
the $100,000 loan is $-882.74.