def ppmt(rate, per, nper, pv, fv=0.0, when='end'):
"""
Not implemented. Compute the payment against loan principal.
Parameters
----------
rate : array_like
Rate of interest (per period)
per : array_like, int
Amount paid against the loan changes. The `per` is the period of
interest.
nper : array_like
Number of compounding periods
pv : array_like
Present value
fv : array_like, optional
Future value
when : {{'begin', 1}, {'end', 0}}, {string, int}
When payments are due ('begin' (1) or 'end' (0))
See Also
--------
pmt, pv, ipmt
"""
m = pmt(rate, nper, pv, fv, when)
if per == 1:
return m
else:
return m - ipmt(rate, per, nper, pv, fv, when)
def ppmt(rate, per, nper, pv, fv=0.0, when='end'):
"""
Not implemented. Compute the payment against loan principal.
Parameters
----------
rate : array_like
Rate of interest (per period)
per : array_like, int
Amount paid against the loan changes. The `per` is the period of
interest.
nper : array_like
Number of compounding periods
pv : array_like
Present value
fv : array_like, optional
Future value
when : {{'begin', 1}, {'end', 0}}, {string, int}
When payments are due ('begin' (1) or 'end' (0))
See Also
--------
pmt, pv, ipmt
"""
m = pmt(rate, nper, pv, fv, when)
if per == 1:
return m
else:
return m - ipmt(rate, per, nper, pv, fv, when)
def loanCalcs(price, percentDown, closingCosts, repairCosts, rate, term):
downPayment = price * percentDown
cashToClose = downPayment + closingCosts
cashToOperate = cashToClose + repairCosts
pv = price - downPayment
nper = term
payment = -pmt(rate, nper, pv)/12
return payment, downPayment, cashToClose, cashToOperate
def ipmt(rate, per, nper, pv, fv=0.0, when='end'):
"""
Not implemented. Compute the payment portion for loan interest.
Parameters
----------
rate : scalar or array_like of shape(M, )
Rate of interest as decimal (not per cent) per period
per : scalar or array_like of shape(M, )
Interest paid against the loan changes during the life or the loan.
The `per` is the payment period to calculate the interest amount.
nper : scalar or array_like of shape(M, )
Number of compounding periods
pv : scalar or array_like of shape(M, )
Present value
fv : scalar or array_like of shape(M, ), optional
Future value
when : {{'begin', 1}, {'end', 0}}, {string, int}, optional
When payments are due ('begin' (1) or 'end' (0)).
Defaults to {'end', 0}.
Returns
-------
out : ndarray
Interest portion of payment. If all input is scalar, returns a scalar
float. If any input is array_like, returns interest payment for each
input element. If multiple inputs are array_like, they all must have
the same shape.
See Also
--------
ppmt, pmt, pv
Notes
-----
The total payment is made up of payment against principal plus interest.
``pmt = ppmt + ipmt``
Gnumeric and KSpread disagree vs. Excel and OO for ipmt(.05/12,100,360,100000,0,1)
Need to derive the results and state assumptions.
"""
m = pmt(rate, nper, pv, fv, when)
when = _convert_when(when)
return -(rate * (pv + when * m) * (1 + rate)**(per - 1 - when) + m *
((1 + rate)**(per - 1 - when) - 1))
def ipmt(rate, per, nper, pv, fv=0.0, when='end'):
"""
Not implemented. Compute the payment portion for loan interest.
Parameters
----------
rate : scalar or array_like of shape(M, )
Rate of interest as decimal (not per cent) per period
per : scalar or array_like of shape(M, )
Interest paid against the loan changes during the life or the loan.
The `per` is the payment period to calculate the interest amount.
nper : scalar or array_like of shape(M, )
Number of compounding periods
pv : scalar or array_like of shape(M, )
Present value
fv : scalar or array_like of shape(M, ), optional
Future value
when : {{'begin', 1}, {'end', 0}}, {string, int}, optional
When payments are due ('begin' (1) or 'end' (0)).
Defaults to {'end', 0}.
Returns
-------
out : ndarray
Interest portion of payment. If all input is scalar, returns a scalar
float. If any input is array_like, returns interest payment for each
input element. If multiple inputs are array_like, they all must have
the same shape.
See Also
--------
ppmt, pmt, pv
Notes
-----
The total payment is made up of payment against principal plus interest.
``pmt = ppmt + ipmt``
Gnumeric and KSpread disagree vs. Excel and OO for ipmt(.05/12,100,360,100000,0,1)
Need to derive the results and state assumptions.
"""
m = pmt(rate, nper, pv, fv, when)
when = _convert_when(when)
return -(rate*(pv+when*m)*(1+rate)**(per-1-when) + m*((1+rate)**(per-1-when)-1))
def PMT(NPER, IPER, PV, FV):
return np.pmt(IPER, NPER, PV, FV, 0)
import numpy.lib.financial as fin # signature of fv fucntion is (Rate,nper(number of years),pmnt (payment),pv(present value), when='end' ) # the following is for rate = %10, one year, 0 payment and $100 principle futVal_1 = fin.fv(0.1,1,0,100) help(fin.fv) futVal_2 = fin.fv(0.1,5,0,100) ''' Here is an example. John is planning to buy a used car with a price tag of $5,000. Assume that he would pay $1,000 as the down payment and borrow the rest. The annual interest rate for a car load is 1.9% compounded monthly. What is his monthly payment if he plans to retire his load in three years? We could calculate the monthly payment manually; see the following code: ''' # manual calculation r=0.019/12 pv=4000 n=3*12 pymnt = pv*r/(1-1/(1+r)**n) pymntPermonth = 200 # Using scipy sp.pmt(r,n,pv) sp.rate(n,pymntPermonth,-pv,0) round(sp.nper(r,-pymntPermonth,-pv,0)) fin.pmt(r,n,pv) fin.rate(n,pymntPermonth,-pv,0)
