Re^4: solve cubic equations (Python)

http://qs1969.pair.com?node_id=1189497

in reply to Re^3: solve cubic equations (Python)
in thread solve cubic equations

Try and solve a few problems on hackerrank.com that way. Their cpu time restrictions are usually too stringent for Math::BigInt, even with a "fast" backend. Python ints are built-in, bignum is an afterthought.

Comment on Re^4: solve cubic equations (Python)

Replies are listed 'Best First'.
Re^5: solve cubic equations (Java) by choroba (Cardinal) on May 04, 2017 at 15:59 UTC
Show me a hackerrank problem that can't be solved in Perl because of time restrictions. The only one I haven't been able to solve in Perl was PRNG Sequnce Guessing, so I solved it in Java. But the problem wasn't the time constraint, but the different behaviour of bit operators on big numbers. ($q=q:Sq=~/;[c](.)(.)/;chr(-\|\|-\|5+lengthSq)`"S\|oS2"`map{chr \|+ord }map{substrSq`S_+\|`\|}3E\|-\|`7**2-3:)=~y+S\|`+$1,++print+eval$q,q,a, [download]	[reply] [d/l]
Re^6: solve cubic equations (Java) by no_slogan (Deacon) on May 05, 2017 at 06:49 UTC
Now that I've had some time to kick it around, this is actually a great example. My Python program solves the sample problem in 1 second. In Perl, using Math::BigInt with the default backend, it takes 10 seconds. With the GMP backend, 5 seconds. With Math::GMP, 1 second, same as Python. By resorting to vile trickery, I was able to get the Perl to run in 0.5 seconds with no modules at all. Here's the kicker, though: the Python program runs in 0.1 second under PyPy (basically JIT compiled Python).	[reply]
Re^7: solve cubic equations (Java) by Anonymous Monk on May 05, 2017 at 08:29 UTC
and with B::CC?	[reply]
Re^7: solve cubic equations (PyPy) by LanX (Saint) on May 05, 2017 at 09:40 UTC
Impressive but > Is PyPy a drop in replacement for CPython? > Almost! > The most likely stumbling block for any given project is support for extension modules. PyPy supports ... mostly only those found in the standard library Cheers Rolf _{(addicted to the Perl Programming Language and ☆☆☆☆ :) Je suis Charlie!}	[reply]
Re^7: solve cubic equations (JavaScript) by LanX (Saint) on May 05, 2017 at 12:50 UTC
Talking about JIT, maybe try benchmarking a JS version too. :) Cheers Rolf _{(addicted to the Perl Programming Language and ☆☆☆☆ :) Je suis Charlie!}	[reply]
Re^7: solve cubic equations (Java) by vrk (Chaplain) on May 05, 2017 at 12:18 UTC
That's intriguing. I admit I've never used Perl's bignum or bigint features for anything serious. Are you able to post short benchmark programs for this? It would be interesting to profile and figure out where the bottleneck is. Which version of Perl, by the way?	[reply]
Re^8: solve cubic equations (Java) by no_slogan (Deacon) on May 05, 2017 at 16:03 UTC
Re^6: solve cubic equations (Java) by no_slogan (Deacon) on May 04, 2017 at 17:04 UTC
Oh look, it's basically the same problem I solved in my old node, Predict Random Numbers. Fifteen years ago. Back then, there wasn't so much information available online, so I actually had to get on my bike and ride to the Stanford math department library to find that algorithm. That problem involves 48-bit numbers, which really aren't all that big. Maybe try something in the Number Theory category. Update: Haha, we didn't have youtube back then either.	[reply]
Re^7: solve cubic equations (Java) by Anonymous Monk on May 04, 2017 at 18:27 UTC
Hey! That was a great node. Lattice basis reduction? Why don't you take a crack at >this< Subset Sum problem? `:-)`	[reply]

In Section Cool Uses for Perl