Question

http://codepad.org/DoJJJoQz -- I was wondering if someone could help me with this code.

First, I want to find a way to list negafibonacci numbers (negative fibonacci numbers) when a user inputs a negative number. I know the algorithm for this, but it always exceeds the recursion limit or gives me a segmentation fault (presumably because the fibonacci algorithm is trying to get to zero and because of the subtraction it will never reach zero inside the sub zero set.)

The other thing I'm having a problem with is displaying the golden ratio when I calculate fib(x)//fib(x-1) Help please?

Answer 1

This part seems to work as long as memo is 'seeded' correctly
http://codepad.org/eRFOsZw1

If you want to extend to negative indices, you have to:
- test the user input for a negative index
- use one formula for positive indices and the other formula for negative indices

if index is positive:
use positive index formula
if index is negative:
use negative index formula

http://codepad.org/q5L2E1mV

Answer 2

Thanks it works like a charm. Now, is there anyway to avoid segmentation faults (when I enter fib(100000))?

Answer 3

i don't even know what that means
http://www.google.com/search?sourceid=chrome&ie=UTF-8&q=is+there+anyway+to+avoid+segmentation+faults+python

Answer 4

I am presuming that the when a number is too large, the computer and python can't cope with it. What about the golden ratio problem?

Answer 5

what do you mean by 'displaying' the golden ratio?? if you want to draw a graph, matplolib is pretty easy to use and very useful
http://en.wikipedia.org/wiki/Golden_ratio#Relationship_to_Fibonacci_sequence

Answer 6

When I divide fib(x-1) into fib(x), it should give me a close approximation of the golden ratio, right? But in my code, it rounds to one.

Answer 7

http://docs.python.org/library/stdtypes.html#numeric-types-int-float-long-complex

Answer 8

Got it to work. Thanks. Though I can't help but think there is a better way to handle it.