math.pow(x,y)

[fl1p-fl0p]

import math
math.pow(34564323, 456356)

will give math range error.

how can i force python to process huge integers without math range
error? Any modules i can use possibly?

 

[Wojciech =?iso-8859-2?Q?Mu=B3a?=]

import math
math.pow(34564323, 456356)

will give math range error.

how can i force python to process huge integers without math range
error? Any modules i can use possibly?

You have to use operator **, i.e. 34564323**456356

 

[Felipe Almeida Lessa]

Em Dom, 2006-06-11 às 11:19 -0700, fl1p-fl0p escreveu:

import math
math.pow(34564323, 456356)

will give math range error.

how can i force python to process huge integers without math range
error? Any modules i can use possibly?

34564323**456356 ?

 

[Gary Herron]

You have to use operator **, i.e. 34564323**456356

That's not very practical. That computation will produce a value with
more than 3.4 million digits. (That is, log10(34564323)*456356 =
3440298.) Python will attempt this, but I was not patient enough to see
if it could calculate an answer today (or even this week).

I doubt that you really *want* all 3.4 million digits. So what is it you
really want? A scientific or engineering result as a floating point
number accurate to some reasonable number of digits? That integer value
modulo some other integer (as used in various cryptology schemes)?

Gary Herron

 

[Raymond L. Buvel]

Em Dom, 2006-06-11 às 11:19 -0700, fl1p-fl0p escreveu:

34564323**456356 ?

I just tried this and it is taking an extremely long time even on a fast
machine with 4 Gb of RAM. Killed it after a couple of minutes. This
sort of calculation can be done with extended precision floating point
(as long as you don't need an exact answer). For example (using
defaults on a 64-bit machine),
mpf('1.39518106833639480699862472257296396643e3440298',36)

compute time is about 160 microseconds.

For more information see

http://calcrpnpy.sourceforge.net/clnumManual.html

For calculations involving large powers, you may still be better off
using logarithms.

 

[K.S.Sreeram]

I just tried this and it is taking an extremely long time even on a fast
machine with 4 Gb of RAM. Killed it after a couple of minutes.

Thats odd.
34564323**456356 completed on my laptop in 28 seconds.
[Python 2.4.3, Celeron-M 1.3GHz, WinXP], and max memory consumption
during the whole process was about 11megs.

What python version are you using?

Regards
Sreeram


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[K.S.Sreeram]

I just tried this and it is taking an extremely long time even on a fast
machine with 4 Gb of RAM. Killed it after a couple of minutes.

You probably tried printing the value.

a = 34564323**456356 (takes just 28 seconds)
whereas
b = str(a) takes forever!

Regards
Sreeram


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[Raymond L. Buvel]

I just tried this and it is taking an extremely long time even on a fast
machine with 4 Gb of RAM. Killed it after a couple of minutes.

Thats odd.
34564323**456356 completed on my laptop in 28 seconds.
[Python 2.4.3, Celeron-M 1.3GHz, WinXP], and max memory consumption
during the whole process was about 11megs.

What python version are you using?

Regards
Sreeram

Sorry, I tripped over the display problem that Tim Peters has repeatedly
explained on this news group (decimal algorithm is quadratic in the
number of digits) :-(

On a 64-bit 2.2 GHz Opteron running Debian stable, Python 2.3 took 26
seconds and Python 2.4 took 11 seconds.

 

[casevh]

You probably tried printing the value.

a = 34564323**456356 (takes just 28 seconds)
whereas
b = str(a) takes forever!

Regards
Sreeram

If you really want all 3,440,299 digits, use the DecInt module..

http://home.comcast.net/~casevh/

Using Python 2.4.3 on a 1.4Ghz Celeron, a=DecInt(34564323) ** 456356
takes 20 seconds. astr=str(a) takes just over 1 second.

With DecInt and GMPY, the running times are 6.9 seconds and 0.4 seconds
respectively.

casevh