Fast nth fibonacci term generator

Here's some code to generate nth fibonacci term with some optimized recursion. Already generated terms are not regenerated. An array acts as a cache for the terms. Besides, integers are represented with char * allowing huge term calculations.

fibogen.c


~/devel/fibogen :) gcc -O3 -march=native -mtune=native -pipe -fomit-frame-pointer -ffast-math -o fibogen fibogen.c
fibogen.c: In function 'main':
fibogen.c:23: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result
~/devel/fibogen :) fibogen
Enter term to calculate: 5023
fibogen(5023) = 248560419649283678513006888062737004960134760988418307905373388505942986481060775195244084194714556882854137612073536664237785579120282065911785293337513886015023953145486883305558080183807994149392421109008029126965116981886956731180641266870009523965481202176011120065634469413284383112960712441923153798256342167123227820469383663417964899013751648010246443960641434024852096101024638451971960625796144677722737304551414781031490411571580459982050355471494276920439983581193010326994482515332997366158457073763985574602205889946564359072664645673996548528062294288463152531141939436109347821144918253984914858266331041933193284095453325649088264822747102089656780678368753206478819515483528828479426315024856137069121990789427595837059650018342996344614879040425051671211007345988321930553661789981247352356512907804456540716374221778890018510373603590988025872815600298159173656785237948221052073363317357008281570513166462291327747202547805549308377844086138173022395933493065635120665887076447216650309115602750732968703082884641717211142536157
Real Time: 0.22, User Time: 0.22, System Time: 0.00


sortwords.c

Oh!, and here's the link to sortwords.c!

http://codepad.org/nLugDQrF

Fun with gcc

Had some fun with gcc today! I once wrote a program that reads words from a file, creates a linked list of the words, and then sorts them alphabetically! For a large text file, the memory overhead is pretty large. So, I used this to benchmark some gcc optimization flags, using all available parameters for the -march= flag!

vikraman@charon ~/scripts/gcc-benchmark $ cat cpu-type-32
native
i386
i486
i586
pentium-mmx
pentiumpro
i686
pentium2
pentium3
pentium-m
pentium4
prescott
nocona
core2
k6
k6-2
athlon
athlon-4
k8
k8-sse3
amdfam10
winchip-c6
winchip2
c3
c3-2
geode

I needed a hufe text file, so I took some issues of phrack, and ended up with a text file containing 1783 words. So, the bash script was:

vikraman@charon ~/scripts/gcc-benchmark $ cat benchmark.sh
#!/bin/bash
for cpu in `cat cpu-type-64`
do
echo $cpu >>benchmark.out
echo "">>benchmark.out
printf "\a"
gcc -march=$cpu -m64 -O3 -pipe -o sortwords sortwords.c
sleep 3
printf "\a"
/usr/bin/time -ao benchmark.out ./sortwords text >/dev/null
printf "\a"
sleep 10
echo "">>benchmark.out
done

And the results:

vikraman@charon ~/scripts/gcc-benchmark $ cat benchmark.out
native

294.93user 1.30system 4:56.81elapsed 99%CPU (0avgtext+0avgdata 0maxresident)k
1712inputs+0outputs (9major+389047minor)pagefaults 0swaps

i386

295.30user 1.34system 4:57.03elapsed 99%CPU (0avgtext+0avgdata 0maxresident)k
0inputs+0outputs (0major+389055minor)pagefaults 0swaps

i486

294.86user 1.34system 4:57.13elapsed 99%CPU (0avgtext+0avgdata 0maxresident)k
0inputs+0outputs (0major+389055minor)pagefaults 0swaps

i586

295.21user 1.33system 4:57.42elapsed 99%CPU (0avgtext+0avgdata 0maxresident)k
0inputs+0outputs (0major+389055minor)pagefaults 0swaps

pentium-mmx

295.13user 1.37system 4:58.77elapsed 99%CPU (0avgtext+0avgdata 0maxresident)k
0inputs+0outputs (0major+389055minor)pagefaults 0swaps

pentiumpro

294.33user 1.28system 4:56.29elapsed 99%CPU (0avgtext+0avgdata 0maxresident)k
0inputs+0outputs (0major+389057minor)pagefaults 0swaps

i686

295.29user 1.56system 5:01.18elapsed 98%CPU (0avgtext+0avgdata 0maxresident)k
0inputs+0outputs (0major+389055minor)pagefaults 0swaps

pentium2

294.67user 1.23system 4:58.56elapsed 99%CPU (0avgtext+0avgdata 0maxresident)k
0inputs+0outputs (0major+389056minor)pagefaults 0swaps

pentium3

297.29user 1.36system 5:00.79elapsed 99%CPU (0avgtext+0avgdata 0maxresident)k
0inputs+0outputs (0major+389057minor)pagefaults 0swaps

pentium-m

294.18user 1.29system 4:58.19elapsed 99%CPU (0avgtext+0avgdata 0maxresident)k
0inputs+0outputs (0major+389057minor)pagefaults 0swaps

pentium4

294.99user 1.49system 4:58.48elapsed 99%CPU (0avgtext+0avgdata 0maxresident)k
0inputs+0outputs (0major+389055minor)pagefaults 0swaps

prescott

294.87user 1.56system 4:58.06elapsed 99%CPU (0avgtext+0avgdata 0maxresident)k
0inputs+0outputs (0major+389056minor)pagefaults 0swaps

nocona

295.71user 1.45system 4:59.41elapsed 99%CPU (0avgtext+0avgdata 0maxresident)k
0inputs+0outputs (0major+389055minor)pagefaults 0swaps

core2

295.35user 1.46system 4:59.52elapsed 99%CPU (0avgtext+0avgdata 0maxresident)k
0inputs+0outputs (0major+389056minor)pagefaults 0swaps

k6

295.04user 1.44system 4:57.40elapsed 99%CPU (0avgtext+0avgdata 0maxresident)k
0inputs+0outputs (0major+389056minor)pagefaults 0swaps

k6-2

295.45user 1.48system 4:58.42elapsed 99%CPU (0avgtext+0avgdata 0maxresident)k
0inputs+0outputs (0major+389057minor)pagefaults 0swaps

athlon

294.66user 1.37system 4:58.69elapsed 99%CPU (0avgtext+0avgdata 0maxresident)k
0inputs+0outputs (0major+389055minor)pagefaults 0swaps

athlon-4

295.32user 1.49system 4:58.14elapsed 99%CPU (0avgtext+0avgdata 0maxresident)k
0inputs+0outputs (0major+389056minor)pagefaults 0swaps

k8

295.48user 1.46system 4:59.84elapsed 99%CPU (0avgtext+0avgdata 0maxresident)k
0inputs+0outputs (0major+389056minor)pagefaults 0swaps

k8-sse3

295.42user 1.52system 4:58.32elapsed 99%CPU (0avgtext+0avgdata 0maxresident)k
0inputs+0outputs (0major+389056minor)pagefaults 0swaps

amdfam10

295.34user 1.49system 4:57.75elapsed 99%CPU (0avgtext+0avgdata 0maxresident)k
0inputs+0outputs (0major+389056minor)pagefaults 0swaps

winchip-c6

298.74user 1.60system 5:02.45elapsed 99%CPU (0avgtext+0avgdata 0maxresident)k
0inputs+0outputs (0major+389057minor)pagefaults 0swaps

winchip2

296.82user 1.29system 4:58.51elapsed 99%CPU (0avgtext+0avgdata 0maxresident)k
0inputs+0outputs (0major+389055minor)pagefaults 0swaps

c3

294.99user 1.39system 4:58.81elapsed 99%CPU (0avgtext+0avgdata 0maxresident)k
0inputs+0outputs (0major+389056minor)pagefaults 0swaps

c3-2

294.38user 1.32system 4:56.74elapsed 99%CPU (0avgtext+0avgdata 0maxresident)k
0inputs+0outputs (0major+389057minor)pagefaults 0swaps

geode

294.53user 1.43system 4:58.47elapsed 99%CPU (0avgtext+0avgdata 0maxresident)k
0inputs+0outputs (0major+389056minor)pagefaults 0swaps

Clearly, -march=pentiumpro wins.
Also, a screenshot from KSysGuard, with the benchmark running!

Yet another reason why we should ditch binary based distributions for source based distributions! Gentoo rocks!

Running KDE 3.5 without arts

I compiled KDE on my gentoo install with -arts USE flag. So I needed an alternative for playing the KDE sound notifications. So I wrote a program in C to launch the appropriate player for each type of audio file, in a forked process.

#include <unistd.h>
#include <stdio.h>
#include <string.h>
int main(int argc, char **argv)
{
if (argc != 2) {
printf("Exactly one argument expected.\n");
return 0;
}
char *ext = strrchr(argv[1], '.');
ext++;
if (ext == NULL) {
return 1;
}
if (fork() == 0) {
if (strcmp(ext, "wav") == 0)
execl("/usr/bin/aplay", "/usr/bin/aplay", "-q", argv[1], NULL);
else if (strcmp(ext, "ogg") == 0)
execl("/usr/bin/ogg123", "/usr/bin/ogg123", "-q", argv[1], NULL);
else if (strcmp(ext, "mp3") == 0)
execl("/usr/bin/mpg123", "/usr/bin/mpg123", "-q", argv[1], NULL);
else
execl("/usr/bin/mplayer", "/usr/bin/mplayer", "-vo", "null", "-really-quiet", argv[1], NULL);
}
return 0;
}

References: http://www.gentoo-wiki.info/TIP_Audio_notifications_in_KDE_3_without_aRts
(Actually there is a mistake in the program on the gentoo wiki which I corrected)

Forum.NOKIA Calling All Innovators contest application demo

This was my application for the Forum.NOKIA Calling All Innovators Contest.

Converting a decimal integer to binary in C

This is some C code that I wrote to convert a decimal integer to its binary equivalent. Most programs written to do so convert the decimal to a string, or an array, of the consecutive remainders modulo 2, which is then printed out in reverse order to get the binary equivalent. However I wanted an integer output of the binary equivalent. So this is what I did.

#include<stdio.h>
int power(int power)
{
int i,p=1;
for(i=0;i<power;i++)
p*=10;
return p;
}
int dectobin(int dec)
{
int bin=0,s[15],i=0,j;
while(dec!=0)
{
s[i]=dec%2;
dec/=2;
i++;
}
for(j=i-1;j>=0;j--)
bin+=s[j]*power(j);
return bin;
}
int main()
{
int num=114;
printf("The binary equivalent of %d is %d\n",num,dectobin(num));
return 0;
}