numpy.rate() in Python

numpy.pmt(rate, nper, pv, fv, when = ‘end’) : This financial function helps user to compute rate of interest per period.

Parameters :
nper : [scalar or (M, )array] total compounding periods
pmt : [scalar or (M, )array] Payment
fv : [scalar or (M, )array] Future value
pv : [scalar or (M, )array] present value
when : at the beginning (when = {‘begin’, 1}) or the end (when = {‘end’, 0}) of each period. Default is {‘end’, 0}

Return : Rate of interest per period.

Equation being solved :

fv + pv*(1+rate)**nper + pmt*(1 + rate*when)/rate*((1 + rate)**nper – 1) == 0

or when rate == 0
fv + pv + pmt * nper == 0

Code:

Output:

Solution= rate  -2.024705182882783