# FW: [PATCH] Bug #24064: Standard deviation - Thread: https://externals.io/message/7682 - Original archive: https://news-web.php.net/php.internals/7682 - Started by Paul Hudson on 2004-02-10T00:53:16+00:00 - Messages: 6 - Reply by email to internals@lists.php.net - More for agents: search with https://externals.io/search.md?q={query} · JSON API at https://externals.io/api · documentation at https://externals.io/llms.txt --- ## #7682 — Paul Hudson — 2004-02-10T00:53:16+00:00 URL: https://externals.io/message/7682#7682 Er, either the php-internals MARC archive doesn't show all attachments, or my diff file got stripped en route for not having a .txt extension. I've attached it again, just to make sure. Paul -- -----Original Message----- From: Paul Hudson [mailto:webjedi@hudzilla.eclipse.co.uk] Sent: 10 February 2004 00:30 To: 'internals@lists.php.net' Subject: [PATCH] Bug #24064: Standard deviation Hi there, Bug #24064 (submitted by tularis@php.net) requests a standard deviation function for PHP. I realise that any of you could implement this in 10 minutes, but according to the bug database it is still Open so I figured I would give it a try myself! There are probably a dozen errors in the code and/or places where it could be better optimised, but I'm hoping one of you might be able to help with that. So, the attached diff file implements the function array_std_dev(), to calculate standard deviation using the deviation method. With the function in place, standard deviation is calculated like this: My first attempt at implementing this was using an extra array to buffer the deviations - this was more out of curiosity to see how the array stuff works. Sadly, it caused PHP to segfault and I couldn't figure out why - can any of you help me spot the brain fart? (I've attached the offending code in bad_stddev_code.txt) Yours, Paul PS: I'm not on the internals list, so I would appreciate it if you would CC me on your reply. --- ## #7685 — Jani Taskinen — 2004-02-10T03:15:26+00:00 URL: https://externals.io/message/7682#7685 · In reply to: #7682 Quickly checked out the patch and first thing to catch my eye was the use of '//' comments. That's a big no-no. (this is not C++) Please read the CODING_STANDARDS couple of times. :) (Use of these C++ comments causes compile failure with some compilers) --Jani >Er, either the php-internals MARC archive doesn't show all attachments, or >my diff file got stripped en route for not having a .txt extension. I've >attached it again, just to make sure. > > >Paul >-- > >-----Original Message----- >From: Paul Hudson [mailto:webjedi@hudzilla.eclipse.co.uk] >Sent: 10 February 2004 00:30 >To: 'internals@lists.php.net' >Subject: [PATCH] Bug #24064: Standard deviation > >Hi there, > >Bug #24064 (submitted by tularis@php.net) requests a standard deviation >function for PHP. I realise that any of you could implement this in 10 >minutes, but according to the bug database it is still Open so I figured I >would give it a try myself! > >There are probably a dozen errors in the code and/or places where it could >be better optimised, but I'm hoping one of you might be able to help with >that. So, the attached diff file implements the function array_std_dev(), >to calculate standard deviation using the deviation method. > >With the function in place, standard deviation is calculated like this: > > $scores = array(18,5,7,18,3,2,10); > print array_std_dev($score); > // prints 6.6833125519211 >?> > >My first attempt at implementing this was using an extra array to buffer the >deviations - this was more out of curiosity to see how the array stuff >works. Sadly, it caused PHP to segfault and I couldn't figure out why - can >any of you help me spot the brain fart? (I've attached the offending code >in bad_stddev_code.txt) > >Yours, > > >Paul > >PS: I'm not on the internals list, so I would appreciate it if you would CC >me on your reply. --- ## #7686 — Andrey Hristov — 2004-02-10T08:15:06+00:00 URL: https://externals.io/message/7682#7686 · In reply to: #7682 Hi, as Derick stated 2 days ago, the problem is not in the extension but in the MIME header. The attachment must be text/plain. Andrey Quoting Paul Hudson : > Er, either the php-internals MARC archive doesn't show all attachments, or > my diff file got stripped en route for not having a .txt extension. I've > attached it again, just to make sure. > > > Paul > -- > > -----Original Message----- > From: Paul Hudson [mailto:webjedi@hudzilla.eclipse.co.uk] > Sent: 10 February 2004 00:30 > To: 'internals@lists.php.net' > Subject: [PATCH] Bug #24064: Standard deviation > > Hi there, > > Bug #24064 (submitted by tularis@php.net) requests a standard deviation > function for PHP. I realise that any of you could implement this in 10 > minutes, but according to the bug database it is still Open so I figured I > would give it a try myself! > > There are probably a dozen errors in the code and/or places where it could > be better optimised, but I'm hoping one of you might be able to help with > that. So, the attached diff file implements the function array_std_dev(), > to calculate standard deviation using the deviation method. > > With the function in place, standard deviation is calculated like this: > > $scores = array(18,5,7,18,3,2,10); > print array_std_dev($score); > // prints 6.6833125519211 > ?> > > My first attempt at implementing this was using an extra array to buffer the > deviations - this was more out of curiosity to see how the array stuff > works. Sadly, it caused PHP to segfault and I couldn't figure out why - can > any of you help me spot the brain fart? (I've attached the offending code > in bad_stddev_code.txt) > > Yours, > > > Paul > > PS: I'm not on the internals list, so I would appreciate it if you would CC > me on your reply. --- ## #7687 — Andrey Hristov — 2004-02-10T08:30:23+00:00 URL: https://externals.io/message/7682#7687 · In reply to: #7682 Hi Paul, may you compile your PHP binary with --enable-debug and after that run your sample scrit for once. See if there are leaks. Andrey Quoting Paul Hudson : > Er, either the php-internals MARC archive doesn't show all attachments, or > my diff file got stripped en route for not having a .txt extension. I've > attached it again, just to make sure. > > > Paul > -- > > -----Original Message----- > From: Paul Hudson [mailto:webjedi@hudzilla.eclipse.co.uk] > Sent: 10 February 2004 00:30 > To: 'internals@lists.php.net' > Subject: [PATCH] Bug #24064: Standard deviation > > Hi there, > > Bug #24064 (submitted by tularis@php.net) requests a standard deviation > function for PHP. I realise that any of you could implement this in 10 > minutes, but according to the bug database it is still Open so I figured I > would give it a try myself! > > There are probably a dozen errors in the code and/or places where it could > be better optimised, but I'm hoping one of you might be able to help with > that. So, the attached diff file implements the function array_std_dev(), > to calculate standard deviation using the deviation method. > > With the function in place, standard deviation is calculated like this: > > $scores = array(18,5,7,18,3,2,10); > print array_std_dev($score); > // prints 6.6833125519211 > ?> > > My first attempt at implementing this was using an extra array to buffer the > deviations - this was more out of curiosity to see how the array stuff > works. Sadly, it caused PHP to segfault and I couldn't figure out why - can > any of you help me spot the brain fart? (I've attached the offending code > in bad_stddev_code.txt) > > Yours, > > > Paul > > PS: I'm not on the internals list, so I would appreciate it if you would CC > me on your reply. --- ## #7697 — Paul Hudson — 2004-02-10T12:33:15+00:00 URL: https://externals.io/message/7682#7697 · In reply to: #7687 Andrey, I compiled with "--enable-debug" already (but did it again just to make sure). It works fine, with no report of leaks. Did I miss something? Jani: You're absolutely right about the comments; sorry about that! Otherwise, is the patch OK to be committed? Paul -- Quoting Andrey Hristov : > Hi Paul, > may you compile your PHP binary with > --enable-debug and after that run your > sample scrit for once. See if there are leaks. > > > Andrey > > Quoting Paul Hudson > : > > > […] > doesn't show all attachments, or > > […] > having a .txt extension. I've > > […] > [mailto:webjedi@hudzilla.eclipse.co.uk] > > […] > deviation > > […] > requests a standard deviation > > […] > could implement this in 10 > > […] > is still Open so I figured I > > […] > and/or places where it could > > […] > might be able to help with > > […] > the function array_std_dev(), > > […] > deviation method. > > […] > is calculated like this: > > […] > using an extra array to buffer the > > […] > see how the array stuff > > […] > couldn't figure out why - can > > […] > attached the offending code > > […] > appreciate it if you would CC > > […] --- ## #7700 — Ard Biesheuvel — 2004-02-10T15:27:51+00:00 URL: https://externals.io/message/7682#7700 · In reply to: #7682 Hi Paul, Why are you comparing, copying and converting each array element twice ? There should be a more elegant way to do this. -- Ard