Hello all
Being a Haskell enthusiastic , first I tried to solve this problem in
Haskell but it running for almost 10 minutes on my computer but not getting
the answer. A similar C++ program outputs the answer almost instant so
could some one please tell me how to improve this Haskell program.
Could Int be overflowing?
On Tue, Nov 8, 2011 at 7:21 PM, mukesh tiwari
mukeshtiwari.ii...@gmail.com wrote:
Hello all
Being a Haskell enthusiastic , first I tried to solve this problem in
Haskell but it running for almost 10 minutes on my computer but not getting
the answer. A similar C++
I am not sure about Int overflow. There is no case of Int overflow in
prime , pList and divPrime function however lets assuming Int overflow in
main but then still answer should be outputted.
Regards
Mukesh Tiwari
On Tue, Nov 8, 2011 at 5:08 PM, Lyndon Maydwell maydw...@gmail.com wrote:
Could
May I suggest you try a non-ST solution first (e.g. using Data.IntMap)
first (assuming an auxiliary data-structure is required)?
Also, I'm not sure if the logic in the two versions is the same: I'm
not sure about how you handle the boolean aspect in C++, but you have
a third for-loop there that
Logic is same. The idea is generate the primes less than 10^8. Now from
each prime , subtract 1 ( when d is 1 then d + n / d = n + 1 should be
prime ) and check for all the divisor. If all divisor are prime then return
True else False
divPrime n = all ( \d - if mod n d == 0 then pList ! ( d +
On 8 November 2011 23:29, mukesh tiwari mukeshtiwari.ii...@gmail.com wrote:
Also, I'm not sure if the logic in the two versions is the same: I'm
not sure about how you handle the boolean aspect in C++, but you have
a third for-loop there that doesn't seem to correspond to anything in
the
In that loop , I am collecting all the primes in vector how ever I changed
the c++ code and now it resembles to Haskell code. This code still gives
the answer within a second.
#includecstdio
#includeiostream
#includevector
#define Lim 10001
using namespace std;
bool prime [Lim];
vectorint
If I compile with optimizations:
ghc --make -O3 primes.hs
I get an answer that is off by one from the C++ program in a few seconds.
On Tue, Nov 8, 2011 at 7:46 AM, mukesh tiwari
mukeshtiwari.ii...@gmail.com wrote:
In that loop , I am collecting all the primes in vector how ever I changed
I forgot to add, I'm on 32-bit GHC and the sum will overflow there, so
I changed main:
main = putStrLn . show . sum $ ([ if and [ pList ! i , divPrime .
pred $ i ] then (fromIntegral $ pred i) else 0 | i - [ 2 .. 10 ^ 8 ]
] :: [Integer])
On Tue, Nov 8, 2011 at 8:19 AM, Ryan Yates
Thank you Ryan . I never compiled my program with -O3 option before and
now i can feel the power of compiler optimisation.
Regards
Mukesh Tiwari
On Tue, Nov 8, 2011 at 6:50 PM, Ryan Yates fryguy...@gmail.com wrote:
I forgot to add, I'm on 32-bit GHC and the sum will overflow there, so
I
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On 11/08/2011 02:19 PM, Ryan Yates wrote:
If I compile with optimizations:
ghc --make -O3 primes.hs
I get an answer that is off by one from the C++ program in a few
seconds.
nice one. Though i wonder. The problem seems to be that without
On Tuesday 08 November 2011, 12:21:14, mukesh tiwari wrote:
Hello all
Being a Haskell enthusiastic , first I tried to solve this problem in
Haskell but it running for almost 10 minutes on my computer but not
getting the answer.
Hmm, finishes in 13.36 seconds here, without any changes.
Of
On Tuesday 08 November 2011, 14:54:18, Silvio Frischknecht wrote:
On 11/08/2011 02:19 PM, Ryan Yates wrote:
If I compile with optimizations:
ghc --make -O3 primes.hs
So far, -O3 is not different from -O2 (-On gives you -O2 for n 2).
*Never* compile code you want to use without
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