Speed And The Incrementation Methods

WaCo

Aug 11 2005, 05:36 AM

"Speed of various incremetation methods"

1) Method one

CODE

[tomek@localhost ebooks]$ LEGAL=1 LEGAL_2=1; LEGAL_3=1;
for i in `seq 100000`; do LEGAL=$(( $LEGAL + 1 ));
LEGAL_2=$(( $LEGAL_2 + 1 ));
LEGAL_3=$(( $LEGAL_3 + 1 )); done;
echo legal\'s value is "$LEGAL"

Avarage amount of time that the process took: 9 seconds 29 hundredth.

2) Method two

CODE

[tomek@localhost ebooks]$ LEGAL=1 LEGAL_2=1;LEGAL_3=1;
for i in `seq 100000`; do LEGAL=$[LEGAL + 1];
LEGAL_2=$[LEGAL_2 + 1];
LEGAL_3=$[LEGAL_3 + 1]; done;
echo legal\'s value is "$LEGAL"

Avarage amount of time that the process took: 6 seconds 99 hundredth.

3) Method three

CODE

[tomek@localhost ebooks]$ LEGAL=1 LEGAL_2=1; LEGAL_3=1;
for i in `seq 100000`; do LEGAL=`echo $LEGAL + 1 | bc`;
LEGAL_2=`echo $LEGAL_2 + 1 | bc`;
LEGAL_3=`echo $LEGAL_3 + 1 | bc`; done;
echo legal\'s value is "$LEGAL"

Avarage amount of time that the process took: 5 000 seconds.

4) Metoda four

CODE

[tomek@localhost ebooks]$ LEGAL=1 LEGAL_2=1; LEGAL_3=1;
for i in `seq 100000`; do LEGAL=`expr $LEGAL + 1`;
LEGAL_2=`expr $LEGAL_2 + 1`;
LEGAL_3=`expr $LEGAL_3 + 1`; done;
echo legal\'s value is "$LEGAL"

Avarage amount of time that the process took: 2 000 seconds.

5) C++ example for comprehension

CODE

#include <iostream>
using namespace std;
int main()
{
float a;
for ( a=1; a <= 10000000; a++ ) { /* 100 x more than in bash !!! */
}
cout << a;
return 0;
}

Avarage amount of time that the process took: not even a second.

Conclusion: The best incrementation method is second method, but compared to hightech programming languages it's still very slow.

Notes: tests were held on Duron 733 Mhz, 128 mb ram, riva tnt 2 32 mb.

[Added 2005-08-11, 07:49:21]

vizskywalker

Aug 12 2005, 06:39 PM

I understand what it is, it is a rundown on various methods of incrementing values and how long they take. It seems to be doing so in batch scripting, perhaps we should ove it there?

~Viz

qwijibow

Aug 27 2005, 08:31 PM

The comparason to c++ is not fair.
You will probably find that the c++ compiler is optimising your code, and replacing

CODE

for ( a=1; a <= 10000000; a++ ) { /* 100 x more than in bash !!! */
}

with the following code

CODE

a=10000000;

both pieces of code achieve the same end result.

try compiling the the zero optimise flag -O0

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Speed And The Incrementation Methods - essay

Speed And The Incrementation Methods - essay