compare execution time C, Python and numpy

abd_bela · 07-07-2022, 05:14 AM

Hi, every body
I write 2 programs : in C and Python to compute the time consumed.
As expected the compile C program ran very fastly compared to Python.
But I am suprised and shocked by the result from Numpy!!!, numpy faster than C.

May be the compared procedure is not correct!!
or error in comparison
Here are my programs and results

The C program the func1 is called N times
given as argument

#include <time.h>
#include <stdio.h>
#include <stdlib.h>
long func1(int n){
long r=0;
for (int i=1; i<= n;i++) r+= i;
return r;
}
int main(int argc, char* argv[]){
clock_t c0, c1;
long v,count; int n;
if ( argc < 2) {
printf("Number of execution as argument");
return -1;
}
n=atoi(argv[1]);
c0 = clock();
for (int j=0;j < n;j++) v=func1(n);
c1 = clock();
printf ("\tCPU time :%.2f sec", (float)(c1 - c0)/CLOCKS_PER_SEC);
printf("\n\tThe value : %ld\n", v);
}
----------------------------------------------------
Python3 Program executed same number times as C

import timeit as it
import numpy as np
import sys
try :
n=eval(sys.argv[1])
except:
print ("Number of execution as argument");
exit()

a=range(1,n+1)
b=np.array(a)
def func1(): return sum(a)
def func2(): return np.sum(b)

print(f"sum with Python: {func1()} and NumPy {func2()} ")
tm1=it.timeit(stmt=func1, number=n)
print(f"time used Python Sum: {round(tm1,2)} sec")
tm2=it.timeit(stmt=func2, number=n)
print(f"time used Numpy Sum: {round(tm2,2)} sec")
'''
Example of execution
./timeC 50000
CPU time :7.66 sec ----------> Consumed by C program
The value : 1250025000

python3 timeExe.py 50000
sum with Python: 1250025000 and NumPy 1250025000
time used Python Sum: 33.0 sec ----------> Consumed by Python
time used Numpy Sum: 1.13 sec ----------> Consumed by Numpy module

'''

Thanks a lot for help or any site for more professional site.

abd_bela · 07-07-2022, 05:16 AM

Hi,
I want to attach a file ,
where to do it
thanks

NevemTeve · 07-07-2022, 05:47 AM

Meta: There is a [Go Advanced] button, press it and you will get many options including attaching files.

On: Numpy is C, just compiled with optimalization.

dugan · 07-07-2022, 08:42 AM

You already had this thread. Same question and same sample code.

is numpy faster than C ?

I was trying to find you the implementation of numpy.sum. I got this instead, and it says the same thing you were told in the other thread:

Why is numpy faster than my c/c++ code for summing an array of float?

astrogeek · 07-07-2022, 10:13 AM

Please post your thread only once and in only one forum. Posting a single thread in the most relevant forum will make it easier for members to help you and will keep the discussion in one place. This thread is being closed because it is a duplicate.

Please continue the discussion in the original thread which has received multiple helpful replies.