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Re: [mv] Prorate discount script bug
****** message to minivend-users from Sydney Urshan <urshan@nethollywood.net> ******
This works perfect:
[loop list='2001 2002 3001 3002']
[discount [loop-code]]
my $bit = $Tag->time('', {}, '%m %d');
my ($month, $n) = split /\s+/, $bit;
$n =~ s/^0//;
my %mon = (
'01' => 31,
'02' => 29,
'03' => 31,
'04' => 30,
'05' => 31,
'06' => 30,
'07' => 31,
'08' => 31,
'09' => 30,
'10' => 31,
'11' => 30,
'12' => 31,
);
if ($mon{$month} and $n > 1) {
return $s - $s * (1 - 1 / $mon{$month}) * ($n - 1) /
($mon{$month} - 1);
}
return $s;
[/discount]
[/loop]
Now to the next step...
I need this exact *result* to work on the if-loop pages (index.html,
etc.) *before* a product is selected. Here is a make-shift solution
I used, but for obvious reasons, it will not always work without
manual changes (like the month).
[if-loop-field monthly]
<B>[currency][calc][loop-field monthly] - ([loop-field monthly] / 31
* [tag time]%d[/tag]) [/calc][/currency]</B></font><BR>
<FONT FACE="Arial" SIZE="2" COLOR=blue><B>Startup Cost Automatically
Prorated [currency][calc][loop-field monthly] - ([loop-field monthly]
- ([loop-field monthly] / 31 * [tag time]%d[/tag]))
[/calc][/currency]!</B>
[else]
<B>[currency][loop-field setup][/currency]</B></font><BR>
<FONT FACE="Arial" SIZE="2" COLOR=blue><B>Not Prorated</B>
[/else]
[/if-loop-field]
Basically, I need the first example to work on index.html before a
product is selected. To see where this would go, see
http://nethollywood.net where it says "See Checkout for Prorated
Amount". (I do not have any calculation script there at this time.)
Thanks again,
Sydney Urshan
Please cc to urshan@nethollywood.net
>Sydney,
>
>Now I understand! I thought everything was being prorated down to $1.00
>at the end of the month. This equation, though a bit more complicated,
>should do the trick:
>
> $s - $s * (1 - 1 / $mon{$month}) * ($n - 1) / ($mon{$month} - 1);
>
>[<start lesson> Derivation (from simple algebra):
> step 1, offset the days by 1 so they become zero-based as it
> simplifies the derivation
> step 2, draw a graph of price vs. time
>
> |
> |\ <-- starting price s
>price | \
> | \
> | \
> | \ <-- ending price e
> |----------> day-in-month - 1
> day ^
> 0 day (mdays - 1)
>
> ending price (e) = starting price (s) / mdays
> slope of the line (m) = (e - s) / (mdays - 1)
>
> step 3, plug the numbers into the standard equation of a line: y = mx + b
> in this case, y is the price and x is the day number (zero-based); b is
> the value on day 0 (which is the initial price). So (using p for
> the price, n for the 1-based day number, mdays for days in a month),
> p = ((e - s) / (mdays - 1)) * (n - 1) + s
> substitue for e:
> p = ((s/mdays - s) / (mdays - 1)) * (n - 1) + s
> factor out -s:
> p = -s * ((-1/mdays + 1) / (mdays - 1)) * (n - 1) + s
> rearrange the order:
> p = s - s * (1 - 1/mdays) * (n - 1) / (mdays - 1)
>
><end of lesson>]
>
> -Bill
>
>
>On Jun 30, 2:33pm, Sydney Urshan wrote:
>} Subject: Re: [mv] Prorate discount script bug
>} ****** message to minivend-users from Sydney Urshan
><urshan@nethollywood.net> ******
>}
>} Bill,
>}
>} I just installed this script (at http://nethollywood.net) to check it
>} out (on the last day of the month). The new result is $1 no matter
>} what the item costs. (Which is better than $0!)
>}
>} Instead, a $20 item today should be $.67 and a $5 item should be
>} $.17. If this month had a different # days, then the results would
>} be different by a few cents. The example below was $1 on the last
>} day because, for simplicity sake, it was a $30 item in a 30 day
>} month. Can you help me tweak it to get it working right?
>}
>} Thanks,
>}
>} Sydney
>}
>} >****** message to minivend-users from Bill Randle
>} ><billr@exgate.tek.com> ******
>} >
>} >Sydney,
>} >
>} >Try this for the calculation:
>} > $s - ($s - 1) * ($n - 1) / ($mon{$month} - 1);
>} >
>} >I tried it for a few test cases and it seems to work for me. You could,
>} >of course, build the length-Of_month-1 value into your month table.
>} >Also, for a little less overhead, you could use localtime() directly,
>} >rather than calling $Tag->time(), as you don't need the formating. E.g.:
>} > my ($sec, $min, $hr, $mday, $mon) = localtime;
>} >If you do that, remember that $mon goes from 0 to 11.
>} >
>} > -Bill
>} >
>} >
>} >Sydney Urshan wrote:
>} > >
>} > > Well, if it's a $30 item in a 30 day month, day 30 should be $1, day
>} > > 29 should be $2...day 2 should be $29, and the first day of the month
>} > > should be $30 with everything else in between adjusted accordingly.
>} > >
>} > > >Sydney Urshan wrote:
>} > > >>
>} > > >> The following discount script works perfect until the last day of
>the
>} > > >> month at which time the result is 0. Can someone help me out on
>this
>} > > >> one?
>} > > >>
>} > > >> [loop list='2001 2002 3001 3002']
>} > > >> [discount [loop-code]]
>} > > >> my $bit = $Tag->time('', {}, '%m %d');
>} > > >> my ($month, $n) = split /\s+/, $bit;
>} > > >> $n =~ s/^0//;
>} > > >> my %mon = (
>} > > >> '01' => 31,
>} > > >> '02' => 29,
>} > > >> '03' => 31,
>} > > >> '04' => 30,
>} > > >> '05' => 31,
>} > > >> '06' => 30,
>} > > >> '07' => 31,
>} > > >> '08' => 31,
>} > > >> '09' => 30,
>} > > >> '10' => 31,
>} > > >> '11' => 30,
>} > > >> '12' => 31,
>} > > >> );
>} > > >> if ($mon{$month} and $n > 1) {
>} > > >> return ($s - ($s / $mon{$month} * $n));
>} > > >> }
>} > > >> return $s;
>} > > >> [/discount]
>} > > >> [/loop]
>} > > >>
>} > > >> Thanks,
>} > > >>
>} > > >> Sydney Urshan
>} > > >
>} > > >Look at your calculation again:
>} > > > $s - ($s / days_in_month * day_of_month);
>} > > >This is equivalent to saying:
>} > > > $s - $s * (days_in_month / day_of_month);
>} > > >when day_of_month is the same as days_in_month, you get
>} > > > $s - $s * 1;
>} > > >which is 0.
>} > > >
>} > > >What did you intend the prorate to be at the end of the month?
>} > > >
>} > > > -Bill
>} -
>} To unsubscribe from the list, DO NOT REPLY to this message. Instead, send
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>Majordomo@minivend.com.
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>}-- End of excerpt from Sydney Urshan
-
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