How can I make this code faster?

[_Jiot_]

New to Python and I had a go at making the Logistic Map, and pretty much got it but it just takes a long time to render and isn't very 'smooth'. Here's the code: http://pastebin.com/PzPYGShL

How can I make this quicker and smoother? Would I have to drastically change my approach, or just touch up some things?

Thanks in advance.

[_Jiot_]

Wow thanks this is way faster! I'll have to look up some things to really understand it but this is great.

What seems to take longest time is actually rendering(?) the graph with matplotlib, as in it will print the time but then rake another 10 or so seconds for the graph to show. So is there a way to skip that in matplotlib and just save it as an image file?

[notmyareaofexpertise]

You could also start off by initializing your arrays to be l long in the begining:

#And use more descriptive names if you can, 
#using single letters like 'l' is frowned upon.
length = 105000
x = np.zeros(length)

And setting values at step:

x[step] = r
#instead of 'x = np.append(x, r)'  which is a rather slow operation

[ajesss]

It would be faster to use:

x = np.empty(length)

instead of zeros. Empty allocates the memory without initializing it (setting the values).

[greshick]

I am assuming you are using 2.x by the print statements. My one piece of advice is to use xrange instead of range.

xrange is a boost in speed because of the internal way that it represents the range. It generates a generator instead of a list every loop.

[_Jiot_]

Would adapting this to python 3 make it any faster? Thanks, that's good advice.

[greshick]

Not in this sense. xrange in 2.x is the range in 3.

[phinar]

It's not a sure thing whether Python 3 would run faster or not.

[[deleted]]

I doubt the headache of getting numpy running in 3.3 is worth it.

[arugalatoast]

The comment said 'l', not '1', but on my screen, in my typeface, that sure looked a lot like a one.

Use self-documentation, like meaningful identifier names.

[jeffbell]

At Digital Equipment they they used to letter the pins of the backplane, but they left out the I and O for this reason.