python - What is the solution/workflow to make use of my functions with Numpy and Matplotlib on the example of cash amount calculations on perpetuity? -

i make matplotlib plot of the amount of cash agglomerated perpetuity against time. use numpy the generation of x axis data.

problem: there seems problem when using functions defined below numpy arrays. suspect has fact functions not vectorized, , there difference between iterative , recursive function definitions. unfortunatly, numpy.vectorize not solve issue.

questions:

how bring example work? , best workflow deal such plotting objectives? whey recursive , iterative functions give different errors? why numpy.vectorize not here?

my code looks this:

agglomerated interest:

def a(a,r,t,n): """calculates combined interest initial amount a, interest rate r, times of compounding per year n , time t.""" return * pow((1 + r/n),(n*t)) 

perpetuity, recursive:

def p_rec(a,r,t,n):     """returns total amount has accumulated perpetuity initial amount a, interest rate r , time t."""     result = 0     if t == 0:          result     else:         result = result + a(a,r,t,n) + p_rec(a,r,(t-1),n)     return result 

perpetuity, iterative:

def p_it(a,r,t,n):     """iterative implemenation of p_rec."""     result = 0     in range(1,t+1):         result = result + a(a,r,i,n)     return result 

vectorized functions creatred numpy.vectorize:

from numpy import vectorize p_rec_v = vectorize (p_rec) p_it_v = vectorize (p_it) 

plotting data:

%matplotlib inline import numpy np import matplotlib.pyplot plt import math  plt.plot(x, a(10,0.16,x,1), 'ro',          x, p_it(10,0.16,x,1), 'g^',          x, p_rec(10,0.16,x,1), 'r--') plt.axis([0, 10, 0, 30]) plt.show() 

errors:

the iterative , recursive version of p function give different errors. not understand why case.

p_rec gives "valueerror: truth value of array more 1 element ambiguous. use a.any() or a.all()"

p_it gives: "typeerror: integer arrays 1 element can converted index"

vectorized p_it: typeerror: 'numpy.float64' object cannot interpreted integer

vectorized p_rec: generates repetitive traceback due recursive nature of function.