Re: Python-on-guile

[Stefan Israelsson Tampe <stefan.itampe@gmail.com>]

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To note is that 'continue' is killing performance for python-on-guile
programs, so by changing the
code to not use continue lead to python-on-guile running twice the speed of
python3. The reason is that
the while loop is used as
(while (...)
   (let/ec continue
        ...))

And the let/ec is probably not optimally compiled. Python-on-guile will
check the loop for continue usage and if not then it will skip the let/ec.

I attached the code not using continue

On Sat, Apr 24, 2021 at 2:59 PM Stefan Israelsson Tampe <
stefan.itampe@gmail.com> wrote:

> Actually changing in (language python compile),
>
> (define (letec f)
>   (let/ec x (f x))))
>
> To
>
> (define-syntax-rule (letec f)
>   (let/ec x (f x))))
>
> Actually lead to similar speeds as python3.
>
>
>
> On Sat, Apr 24, 2021 at 1:26 PM Stefan Israelsson Tampe <
> stefan.itampe@gmail.com> wrote:
>
>> Pro tip, when running this on guile the scheme code that it compilse to
>> is located in log.txt.
>> If you ,opt the resulting code in a guile session you might be able to
>> pinpoint issues that
>> delays the code execution.
>>
>> On Sat, Apr 24, 2021 at 12:04 PM Mikael Djurfeldt <mikael@djurfeldt.com>
>> wrote:
>>
>>> (I should perhaps add that my script doesn't benchmark the object system
>>> but rather loops, conditionals and integer arithmetic.)
>>>
>>> Den fre 23 apr. 2021 17:00Mikael Djurfeldt <mikael@djurfeldt.com> skrev:
>>>
>>>> Hi,
>>>>
>>>> Yesterday, Andy committed new code to the compiler, some of which
>>>> concerned skipping some arity checking.
>>>>
>>>> Also, Stefan meanwhile committed something called "reworked object
>>>> system" to his python-on-guile.
>>>>
>>>> Sorry for coming with unspecific information (don't have time to track
>>>> down the details) but I noticed that my benchmark script written in Python,
>>>> and which computes the 20:th Ramanujan number, now runs 60% faster than
>>>> before these changes.
>>>>
>>>> This means that python-on-guile running on guile3 master executes
>>>> python code only 2.6 times slower than the CPython python3 interpreter
>>>> itself. :-)
>>>>
>>>> Have a nice weekend all,
>>>> Mikael
>>>>
>>>>

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#  ramanujan.py -- Compute the N:th Ramanujan number
#  
#  Copyright (C) 2018-2021 Mikael Djurfeldt
#
#  This program is free software; you can redistribute it and/or modify
#  it under the terms of the GNU General Public License as published by
#  the Free Software Foundation; either version 3 of the License, or
#  (at your option) any later version.
#
#  This program is distributed in the hope that it will be useful,
#  but WITHOUT ANY WARRANTY; without even the implied warranty of
#  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#  GNU General Public License for more details.
#
#  You should have received a copy of the GNU General Public License
#  along with this program.  If not, see <http://www.gnu.org/licenses/>.
#

# Version 2

# return the N:th Ramanujan number (sum of two cubes in more than one way)
#
def ramanujan (n):
    w = 0 # Ramanujan number candidate
    b0 = 1 # first second term to try
    while n > 0:
        w += 1 # try next candidate

        # increase initial b0 until 1 + b0^3 >=w
        while 1 + b0 * b0 * b0 < w:
            b0 += 1
            
        a = 1
        a3 = 1
        b = b0
        b3 = b0 * b0 * b0
        count = 0 # number of ways to write w
        while a <= b:
            s = a3 + b3
            if s < w:
                a += 1 # if sum is too small, increase a
                a3 = a * a * a
            elif s == w:
                count += 1 # found a sum!
                if count > 1:
                    n -= 1
                    break
                b -= 1 # increase b both if sum too large and to find next way to write w
                b3 = b * b * b
            else:
                b -= 1 
                b3 = b * b * b
                
    return w

print (ramanujan (21))