Different result compared to python

[siyavashmoradi]

Here is a test with codon:

import time

st = time.time() sum_x = 0 for i in range(10000000000): sum_x += i time.sleep(3) print('Sum of first 10 bilion numbers is:', sum_x) et = time.time() elapsed_time = et - st print('Execution time:', elapsed_time, 'seconds')

Here is the result with python3:

python3 test.py Sum of first 10 bilion numbers is: 49999999995000000000 Execution time: 557.8164610862732 seconds

Here is the result with codon:

codon run -release test.py Sum of first 10 bilion numbers is: -5340232226128654848 Execution time: 3.00534 seconds

As you can see the answer with codon is completely wrong.

[elisbyberi]

@siyavashmoradi I cannot reproduce the error:

import time

# S = N * (N + 1) / 2

size: Static[int] = 128  # S > 64-bit integer
exp = 10
N = UInt[size](10 ** exp)
result = UInt[size](0)

st = time.time()
start = 1
stop = int(N + UInt[size](1))
for i in range(start, stop):
    result += UInt[size](i)

et = time.time()
elapsed_time = et - st

print('Sum: ', result, str(result), len(str(result)))
print('Execution time:', elapsed_time, 'seconds')

# test result
test = N * (N + UInt[size](1))  # / 2  # do not use float
assert test == result * UInt[size](2)

prints:

Sum:  50000000005000000000 50000000005000000000 20
Execution time: 0 seconds

Python code to test result:

N = 10 ** 10
test = N * (N + 1)  # / 2  # do not use float
print(test)

[siyavashmoradi]

It's probably because I forgot to put the indent after the for loop, with the indent for the line "sum_x += I" you can probably reproduce the results

Also in the for loop if I put 10e+9 it works just fine, but if I go higher it gives wrong result

[kellantech]

Codon integers are 64 bits by default, but the answer must be stored in at least 66 bit ints.

[siyavashmoradi]

Codon integers are 64 bits by default, but the answer must be stored in at least 66 bit ints.

Thanks. didn't know it.

[inumanag]

Yes, Codon integers by default are 64-bit ints. See https://docs.exaloop.io/codon/general/differences for how to use Python integers (with a warning; performance might suffer).