On Tue, Mar 24, 2015 at 5:41 AM, Steven D'Aprano
steve+comp.lang.pyt...@pearwood.info wrote:
Python does not automatically print all return statements. If you want it to
print the intermediate values produced, you will need to add print before
each return:
py def fib(n):
... if n == 0:
On Tue, Mar 24, 2015 at 12:20 AM, Rustom Mody rustompm...@gmail.com wrote:
On Tuesday, March 24, 2015 at 10:51:11 AM UTC+5:30, Ian wrote:
Iteration in log space. On my desktop, this calculates fib(1000) in
about 9 us, fib(10) in about 5 ms, and fib(1000) in about 7
seconds.
def
On Tuesday, March 24, 2015 at 10:24:59 PM UTC+8, Ian wrote:
On Tue, Mar 24, 2015 at 12:20 AM, Rustom Mody rustompm...@gmail.com wrote:
On Tuesday, March 24, 2015 at 10:51:11 AM UTC+5:30, Ian wrote:
Iteration in log space. On my desktop, this calculates fib(1000) in
about 9 us, fib(10)
On Tuesday, March 24, 2015 at 11:50:40 AM UTC+5:30, Rustom Mody wrote:
On Tuesday, March 24, 2015 at 10:51:11 AM UTC+5:30, Ian wrote:
On Mon, Mar 23, 2015 at 4:53 PM, Terry Reedy wrote:
Iteration with caching, using a mutable default arg to keep the cache
private and the function
On 03/23/2015 08:27 PM, Chris Angelico wrote:
On Tue, Mar 24, 2015 at 11:09 AM, Dave Angel d...@davea.name wrote:
Repeat to self: comment first, then write test, then write the code.
Reply to self: Maybe next time.
Commenting is like dieting. You can always start tomorrow.
It reminds me
On Tuesday, March 24, 2015 at 10:51:11 AM UTC+5:30, Ian wrote:
On Mon, Mar 23, 2015 at 4:53 PM, Terry Reedy wrote:
Iteration with caching, using a mutable default arg to keep the cache
private and the function self-contained. This should be faster.
def fib(n, _cache=[0,1]):
On Tuesday, March 24, 2015 at 6:54:20 AM UTC+8, Terry Reedy wrote:
On 3/23/2015 2:44 PM, Dave Angel wrote:
## Example 2: Using recursion with caching
cache = [0, 1]
def fib4(n):
if len(cache) = n:
value = fib4(n-2) + fib4(n-1)
cache.append(value)
return
Chris Angelico wrote:
Commenting is like dieting. You can always start tomorrow.
I've been meaning to become a procrastinator, but
I think I'll start tomorrow.
In the meantime, since we seem to be having a
fibbing competition, here's my contribution, that
uses neither recursion nor (explicit)
On Mon, Mar 23, 2015 at 4:53 PM, Terry Reedy tjre...@udel.edu wrote:
Iteration with caching, using a mutable default arg to keep the cache
private and the function self-contained. This should be faster.
def fib(n, _cache=[0,1]):
'''Return fibonacci(n).
_cache is initialized with
On Tue, Mar 24, 2015 at 3:01 AM, Ganesh Pal ganesh1...@gmail.com wrote:
Hello team ,
[root@localhost Python]# cat fibonacci-Sequence-3.py
## Example 2: Using recursion
def fib(n):
if n == 0:
return 0
elif n == 1:
return 1
else:
return fib(n-1) +
Hello team ,
[root@localhost Python]# cat fibonacci-Sequence-3.py
## Example 2: Using recursion
def fib(n):
if n == 0:
return 0
elif n == 1:
return 1
else:
return fib(n-1) + fib(n-2)
print fib(5)
# python fibonacci-Sequence-3.py
5
what Iam I missing in
On 03/23/2015 12:01 PM, Ganesh Pal wrote:
Hello team ,
[root@localhost Python]# cat fibonacci-Sequence-3.py
## Example 2: Using recursion
def fib(n):
if n == 0:
return 0
elif n == 1:
return 1
else:
return fib(n-1) + fib(n-2)
print fib(5)
# python
On Mon, Mar 23, 2015 at 12:44 PM, Dave Angel da...@davea.name wrote:
On 03/23/2015 12:16 PM, Chris Angelico wrote:
[1] Cue the demonstration of a worse version from someone's student?
I'll give you a worse version. Back in the day I had occasion to write a
simple program in a language which
On 23/03/15 19:44, Dave Angel wrote:
I'll give you a worse version. Back in the day I had occasion to write a
simple program
in a language which had no add or subtract. It could only increment and
decrement
indices.
Oh yes, the olden days. I have not quite lived through the punch card era,
On Tue, Mar 24, 2015 at 3:16 AM, Dave Angel da...@davea.name wrote:
An entirely separate question is whether you can gain performance by caching
intermediate values. For example, if you capture values in a list, you
could potentially save a lot of time, at least for non-trivial values of n.
On Tuesday, March 24, 2015 at 1:00:11 AM UTC+8, Chris Angelico wrote:
On Tue, Mar 24, 2015 at 3:16 AM, Dave Angel da...@davea.name wrote:
An entirely separate question is whether you can gain performance by caching
intermediate values. For example, if you capture values in a list, you
On 03/23/2015 12:16 PM, Chris Angelico wrote:
On Tue, Mar 24, 2015 at 3:01 AM, Ganesh Pal ganesh1...@gmail.com wrote:
Hello team ,
[root@localhost Python]# cat fibonacci-Sequence-3.py
## Example 2: Using recursion
def fib(n):
if n == 0:
return 0
elif n == 1:
On 03/23/2015 12:59 PM, Chris Angelico wrote:
On Tue, Mar 24, 2015 at 3:16 AM, Dave Angel da...@davea.name wrote:
An entirely separate question is whether you can gain performance by caching
intermediate values. For example, if you capture values in a list, you
could potentially save a lot of
On Tue, 24 Mar 2015 03:16 am, Chris Angelico wrote about the standard
recursive version of the Fibonacci series:
On Tue, Mar 24, 2015 at 3:01 AM, Ganesh Pal ganesh1...@gmail.com wrote:
def fib(n):
if n == 0:
return 0
elif n == 1:
return 1
else:
return
On 03/23/2015 05:31 PM, Carsten Lechte wrote:
On 23/03/15 19:44, Dave Angel wrote:
I'll give you a worse version. Back in the day I had occasion to
write a simple program
in a language which had no add or subtract. It could only increment
and decrement
indices.
Oh yes, the olden days. I
On 03/23/2015 07:49 PM, Chris Angelico wrote:
On Tue, Mar 24, 2015 at 10:12 AM, Dave Angel da...@davea.name wrote:
On the other hand, my loop makes some non-obvious assumptions, like that
append is always the right place to put a new value.
Yes, I had to stop and think about that one a bit.
On Tue, Mar 24, 2015 at 10:12 AM, Dave Angel da...@davea.name wrote:
On the other hand, my loop makes some non-obvious assumptions, like that
append is always the right place to put a new value.
Yes, I had to stop and think about that one a bit. And that strongly
suggests (to me, at least!)
On Tue, Mar 24, 2015 at 11:19 AM, Steven D'Aprano
steve+comp.lang.pyt...@pearwood.info wrote:
It is pretty inefficient, but it is a good toy example of recursion. It's
also a good example of how *not* to write the Fibonacci series in practice,
what is mathematically straightforward is not
On 03/23/2015 06:53 PM, Terry Reedy wrote:
On 3/23/2015 2:44 PM, Dave Angel wrote:
## Example 2: Using recursion with caching
cache = [0, 1]
def fib4(n):
if len(cache) = n:
value = fib4(n-2) + fib4(n-1)
cache.append(value)
return cache[n]
This one takes less than a
On Tue, 24 Mar 2015 03:01 am, Ganesh Pal wrote:
Hello team ,
[root@localhost Python]# cat fibonacci-Sequence-3.py
## Example 2: Using recursion
def fib(n):
if n == 0:
return 0
elif n == 1:
return 1
else:
return fib(n-1) + fib(n-2)
print fib(5)
On Tue, Mar 24, 2015 at 11:09 AM, Dave Angel d...@davea.name wrote:
Repeat to self: comment first, then write test, then write the code.
Reply to self: Maybe next time.
Commenting is like dieting. You can always start tomorrow.
ChrisA
--
https://mail.python.org/mailman/listinfo/python-list
Given the standard recursive version of the Fibonacci series:
def fib(n):
if n == 0:
return 0
elif n == 1:
return 1
else:
return fib(n-1) + fib(n-2)
I asked:
The question is, just how inefficient is is? How many calls to `fib` are
made in calling fib(n)?
On 3/23/2015 2:44 PM, Dave Angel wrote:
## Example 2: Using recursion with caching
cache = [0, 1]
def fib4(n):
if len(cache) = n:
value = fib4(n-2) + fib4(n-1)
cache.append(value)
return cache[n]
This one takes less than a millisecond up to n=200 or so.
Iteration
On 03/23/2015 08:19 PM, Steven D'Aprano wrote:
On Tue, 24 Mar 2015 03:16 am, Chris Angelico wrote about the standard
recursive version of the Fibonacci series:
On Tue, Mar 24, 2015 at 3:01 AM, Ganesh Pal ganesh1...@gmail.com wrote:
def fib(n):
if n == 0:
return 0
elif n
On 3/23/2015 7:12 PM, Dave Angel wrote:
On 03/23/2015 06:53 PM, Terry Reedy wrote:
Iteration with caching, using a mutable default arg to keep the cache
private and the function self-contained. This should be faster.
def fib(n, _cache=[0,1]):
'''Return fibonacci(n).
_cache is
On Tue, 24 Mar 2015 11:59 am, Chris Angelico wrote:
I've never thought of the mathematical definition as being inherently
recursive; but as inherently sequential. Sure, you can define counting
numbers based on sets (0 is the cardinality of the empty set, 1 is the
cardinality of the set
On Tuesday, March 24, 2015 at 8:33:24 AM UTC+5:30, Chris Angelico wrote:
On Tue, Mar 24, 2015 at 12:52 PM, Steven D'Aprano wrote:
On Tue, 24 Mar 2015 11:59 am, Chris Angelico wrote:
I've never thought of the mathematical definition as being inherently
recursive; but as inherently
On Tuesday, March 24, 2015 at 8:33:24 AM UTC+5:30, Chris Angelico wrote:
Mathematics doesn't like defining sequences, except by defining
functions, and so it has to convert the concept of defining the
Fibonacci sequence into defining a function F(N) which returns the
Nth Fibonacci number, and
On Tuesday, March 24, 2015 at 7:22:25 AM UTC+5:30, Steven D'Aprano wrote:
On Tue, 24 Mar 2015 11:59 am, Chris Angelico wrote:
I've never thought of the mathematical definition as being inherently
recursive; but as inherently sequential. Sure, you can define counting
numbers based on
On Tue, Mar 24, 2015 at 12:52 PM, Steven D'Aprano
steve+comp.lang.pyt...@pearwood.info wrote:
On Tue, 24 Mar 2015 11:59 am, Chris Angelico wrote:
I've never thought of the mathematical definition as being inherently
recursive; but as inherently sequential. Sure, you can define counting
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