Precizion

Question

Hello
One of my exercise was to give a certain number of decimal of the Pi number.
So I started by trying to calcuate pi using the Nilakantha series, then I make python write x decimal of the Pi number.
My issue is that the precizion of the calculation is super low.
I am doing 20 square 5 iteration and I am only precize up to 13 numbers...

How do you do to increase the precizion on the whole code if that's possible ?

p = int(input('How many digit do for Pi do you need ?\n'))

x = 2
v = 0
h = 1
pi = 3
while v <= 20**5:
b = h*4/(x*(x+1)*(x+2))
pi += b
h *= -1
x += 2
v += 1

print(f" your number is {f'{pi:.{p+1}}'}")

Answer 1

Thanks Alexandr
But running this code, I only reach 19 digits.
So the issue is not python but the NilaKantha series itself.

Answer 2

Yes I saw this formula when I did a search on the subject :-) .
But my objectif is more to learn python than mathematic, so I stick to a formula easy to code.
Still I would have think that my serie would ge more digit especially with so many iteration.

Answer 3

Hello thanks for the input.
I know that my algorithm is basic. I am doing a course on Udemy (from zero to hero in python) and I am at the last milestone project, they just give you a list of task to do.
Yesterday I had a look at the the one about pi, they ask you to calculate pi but I am more in to learn python than doing mathematic :-).
I am ok with a basic algorithm , but I am not ok with so low a precision because that's not the algorithm at fault but my coding.