Multiprecision integers - part 2
This time I benchmark small sums among multiprecision integers (MPI). This kind of operation is interesting because it shows how well such multiprecision integers can replace normal integer operations, to avoid integer overflows but keep running efficiency as much as possible. Among the ones I have tested the Python integral numbers seem the most fit for this purpose. Probably the libs I have tested aren't much fit for this. Probably the results for Python3 are worse (even when Psyco will be available for it).

TIMINGS, N = 1_000_000 * 10, best of 3:

#program, seconds run:
#2  D:        0.027 s (LDC)
#1  Python:   0.34  s (+ Psyco)
#5  C:        1.04  s (+ GMP)
#3  Python:  11.7   s (+ Psyco + GMPY)
#4  D:       21.2   s (LDC + Tango)
#6  C++:              (+ GMP)
#7  Java:

PROGRAM OUTPUT: 45000000

-----------------

UPDATE Feb 11 2009:

Indeed, the LLVM backend is able to optimize away the loops of
 the D program #2, this is a version with printing:

import tango.stdc.stdio: printf;
void main() {
    int n = 0;
    for (int j; j < 1_000_000; j++)
        for (int i; i < 10; i++)
            n += i;
    printf("%d\n", n);
}

Compiling with -O2 -inline -release, such extreme optimization
 isn't performed, this is the asm generated:

	subl	$12, %esp
	xorl	%eax, %eax
	movl	%eax, %ecx
	.align	16
.LBB1_1:	# forcond
	cmpl	$999999, %eax
	jg	.LBB1_6	# endfor
.LBB1_2:
	xorl	%edx, %edx
	.align	16
.LBB1_3:	# forcond2
	cmpl	$9, %edx
	jg	.LBB1_5	# forinc
.LBB1_4:	# forbody3
	addl	%edx, %ecx
	incl	%edx
	jmp	.LBB1_3	# forcond2
.LBB1_5:	# forinc
	incl	%eax
	jmp	.LBB1_1	# forcond
.LBB1_6:	# endfor
	movl	%ecx, 4(%esp)
	movl	$.str1, (%esp)
	call	printf

But the total running time is minimal anway, 0.027 s or less, such
 timign is lost in noise.

In all the other programs the compilers/interpreters can't optimize
 away the loops, mostly because they use multiprecision integers.

-----------------

PROGRAMS:

# program #1, Python with Psyco
import psyco
def main():
    n = 0
    for j in xrange(1000000):
        for i in xrange(10):
            n += i
    return n   
psyco.bind(main)
main()



// program #2, D
void main() {
    int n = 0;
    for (int j; j < 1_000_000; j++)
        for (int i; i < 10; i++)
            n += i;
}



# program #3, Python with Psyco, gmpy
import psyco
from gmpy import mpz
def main():
    n = mpz(0)
    for j in xrange(1000000):
        for i in xrange(10):
            n += i
    return n
psyco.bind(main)
main()



// program #4, D with BigInt
import tango.math.BigInt: BigInt;
void main() {
    BigInt n = "0";
    for (int j; j < 1_000_000; j++)
        for (int i; i < 10; i++)
            n += i;
}



// program #5, C with GMP
#include "stdio.h"
#include "gmp.h"
int main(void) {
    mpz_t n;
    int i, j;
    mpz_init_set_si(n, 0);
    for (j = 0; j < 1000000; j++)
        for (i = 0; i < 10; i++)
            mpz_add_ui(n, n, i);
    mpz_out_str(0, 10, n);
    putchar('\n');   
    return 0;
}



// program #6, C++ with GMP (not tested)
#include <iostream>
#include <gmpxx.h>
int main() {
    mpz_class n;
    int i, j;
    n = 0;
    for (j = 0; j < 1000000; j++)
        for (i = 0; i < 10; i++)
            n += i;   
    std::cout << n << "\n";
    return 0;
}



// program #7, Java (not tested)
import java.math.BigInteger;
public class bigint_small_sum_7 {
    public static void main(String[] args) {
        BigInteger n = BigInteger.ZERO;
        for (int j = 0; j < 1000000; j++)
            for (int i = 0; i < 10; i++)
                n = n.add(BigInteger.valueOf(i));
    }
}

-----------------

CPU: Pentium3 @ 500 MHz, 256 MB RAM
OS: Ubuntu 8.10.

Timings are "real" seconds found with the 'time' command
(the best from 3+ consecutive runs).

VM/compiler/libs used:
- Python V.2.5.2
- Psyco V.1.6.0
- GMPY V.1.02
- GMP V.4.2.4
- gcc V.4.3.2 (Ubuntu 4.3.2-1ubuntu12)
- ldc rev.939, on dmd v1.039 + llvm 2.4 (Feb 4 2009)
- java 1.6.0_10

Code compiled with:
ldc -O3 -release -inline bigint_small_sum_2.d
ldc -O3 -release -inline bigint_small_sum_4.d  
gcc -O3 -s bigint_small_sum_5.c -o bigint_small_sum_5 -lgmp
g++ bigint_small_sum_6.cpp -o bigint_small_sum_6 -lgmpxx -lgmp
javac bigint_small_sum_7.java