Discard formula

Imported from Yahoo
1

What is the correct formula for "The number of races to be counted
in a series shall be calculated as 50% plus 1 (rounded down to a
whole number) of the number of

  down to a whole number) of the

number of

races completed for each class"

I have used (s/2 +1) but it gives incorrect results for classes that

have not sailed all the races. I’m guessing its something to do with
the rounding. We need to round down the result of s/2 but I thought
that was the default set in Sailwave.

Any advice would be hugely appreciated as I'm being hassled to get

it right.

··· 
-- Kind regards
Graham Pinkney

office@stmawessailing.co.uk

2

The sailing Instruction states the number of races to count, Sailwave needs to know the number of races to discard. Your discard profile formula calculates the number of races to keep, not discard.

If “The number of races to be counted in a series shall be calculated as 50% plus 1 (rounded down to a whole number) of the number of down to a whole number) of the number of races completed for each class”. Then the number of races to be discarded

Can you provide an example where “it gives incorrect results for classes that have not sailed all the races”.

···

To: sailwave@yahoogroups.com
CC: office@stmawessailing.co.uk
From: sailwave@yahoogroups.com
Date: Sat, 27 Sep 2014 12:00:53 +0100
Subject: [sailwave] Discard formula

What is the correct formula for "The number of races to be counted

in a series shall be calculated as 50% plus 1 (rounded down to a
whole number) of the number of
down to a whole number) of the
number of

races completed for each class"

I have used (s/2 +1) but it gives incorrect results for classes that

have not sailed all the races. I’m guessing its something to do with
the rounding. We need to round down the result of s/2 but I thought
that was the default set in Sailwave.

Any advice would be hugely appreciated as I'm being hassled to get

it right.

-- Kind regards
Graham Pinkney
office@stmawessailing.co.uk
3

I was sat outside St Maws sailing club eating an ice cream and watching your racing a few weeks ago. Nice location :slight_smile:

···

Cheers,

Colin J

http://sailwave.com

On Sat, Sep 27, 2014 at 12:00 PM, St Mawes SC office@stmawessailing.co.uk [sailwave] sailwave@yahoogroups.com wrote:

What is the correct formula for "The number of races to be counted

in a series shall be calculated as 50% plus 1 (rounded down to a
whole number) of the number of

  down to a whole number) of the

number of

races completed for each class"

I have used (s/2 +1) but it gives incorrect results for classes that

have not sailed all the races. I’m guessing its something to do with
the rounding. We need to round down the result of s/2 but I thought
that was the default set in Sailwave.

Any advice would be hugely appreciated as I'm being hassled to get

it right.

-- Kind regards
Graham Pinkney
office@stmawessailing.co.uk
4

Hi Mark

First, many thanks for the quick reply, its much appreciated.
The background is that I have always used the 0,0,1,2,3 etc method

under the Series Scoring page, thus the discard profile applied to
all fleet. If a fleet chose not to race they got a DNC. Nobody
complained but our Commodore decided that each fleet should have its
own discard profile, changing dynamically as the number of races
increases per fleet which I thought could be done via the Fleets
setting. However, thinking about it I decided that if I change the
profile to a formula and then not use the fleets menu, it would
automatically take care of the differing numbers of races. As you
say, the profile calculates the number of discards, not the number
to count. I can see that actually all the discards are wrong so
ignore the bit about some classes not sailed.

So, I suppose the question is how do I make a formula that works the

right way round.
�I have attached a test version of our Summer Sunday series but note
that the race titles can be confusing because I keep the race name
the same for a given date even if a fleet did not race. ie. 20th
July is called SS5 but for the 18footer fleet it was their 2nd race.

The unedited version using the o,o,1 etc method is on our results

page at
in
case that helps.

···

http://www.stmawessailing.co.uk/sailing/racing/results/index.php

   On 27/09/2014 15:40, Mark Townsend

[sailwave] wrote:

          The sailing Instruction states the number of races to

count, Sailwave needs to know the number of races to
discard. Your discard profile formula calculates the
number of races to keep, not discard.

          If "The number of races to be counted in a series shall be

calculated as 50% plus 1 (rounded down to a whole number)
of the number of down to a whole number) of the number of
races completed for each class". Then the number of races
to be discarded

          Can you provide an example where "it gives incorrect

results for classes that have not sailed all the races".

          To: CC: From: Date: Sat, 27 Sep 2014 12:00:53 +0100

Subject: [sailwave] Discard formula

-- Kind regards
Graham Pinkney

s_mark_townsend@hotmail.com
sailwave@yahoogroups.com
office@stmawessailing.co.uk
sailwave@yahoogroups.com

�
What is the correct formula
for "The number of races to be counted in a series
shall be calculated as 50% plus 1 (rounded down to a
whole number) of the number of
down
to a whole number) of the number of

races completed for each class"

                I have used (s/2 +1) but it gives incorrect results

for classes that have not sailed all the races. I’m
guessing its something to do with the rounding. We
need to round down the result of s/2 but I thought
that was the default set in Sailwave.

                Any advice would be hugely appreciated as I'm being

hassled to get it right.

-- Kind regards
Graham Pinkney
office@stmawessailing.co.uk

office@stmawessailing.co.uk

5

Graham,

You've already done the work!!

The number to keep is the total minus the discards, so the number to
discard is the total minus the number to keep.

Total = s
Number to keep = (s/2)+1 [you specified this]
So, Number to discard = s - ((s/2)+1)

This generates a number of races to discard, which is then truncated.
5 races is 5/2 [2.5] plus one [3.5] subtracted from 5 [1.5] truncated to
1 discard. 6 races is 6/2 [3] plus one [4] subtracted from 6 [2]
truncated to 2 discards.

You can test your formula by clicking on the big SIGMA symbol.

By the way, specifying a discard profile would produce exactly the same
result. It automatically applies the profile to the number of races held
for each fleet. There is no effective difference between the two
methods; the difference is you won't make a mistake when doing a
race-by-race profile if you use the correct formula. I'd recommend using
the testing function to test the full number of races expected to be
sure your formula always does what you expect.

Art

···

On 9/27/2014 10:02 AM, St Mawes SC office@stmawessailing.co.uk [sailwave] wrote:

Hi Mark

First, many thanks for the quick reply, its much appreciated.
The background is that I have always used the 0,0,1,2,3 etc method under the
Series Scoring page, thus the discard profile applied to all fleet. If a fleet
chose not to race they got a DNC. Nobody complained but our Commodore decided
that each fleet should have its own discard profile, changing dynamically as the
number of races increases per fleet which I thought could be done via the Fleets
setting. However, thinking about it I decided that if I change the profile to a
formula and then not use the fleets menu, it would automatically take care of
the differing numbers of races. As you say, the profile calculates the number of
discards, not the number to count. I can see that actually all the discards are
wrong so ignore the bit about some classes not sailed.

So, I suppose the question is how do I make a formula that works the right way
round.
  I have attached a test version of our Summer Sunday series but note that the
race titles can be confusing because I keep the race name the same for a given
date even if a fleet did not race. ie. 20th July is called SS5 but for the
18footer fleet it was their 2nd race.
The unedited version using the o,o,1 etc method is on our results page at
http://www.stmawessailing.co.uk/sailing/racing/results/index.php in case that helps.

On 27/09/2014 15:40, Mark Townsend s_mark_townsend@hotmail.com [sailwave] wrote:

The sailing Instruction states the number of races to count, Sailwave needs to
know the number of races to discard. Your discard profile formula calculates
the number of races to keep, not discard.

If "The number of races to be counted in a series shall be calculated as 50%
plus 1 (rounded down to a whole number) of the number of down to a whole
number) of the number of races completed for each class". Then the number of
races to be discarded

Can you provide an example where "it gives incorrect results for classes that
have not sailed all the races".

--------------------------------------------------------------------------------
To: sailwave@yahoogroups.com
CC: office@stmawessailing.co.uk
From: sailwave@yahoogroups.com
Date: Sat, 27 Sep 2014 12:00:53 +0100
Subject: [sailwave] Discard formula

What is the correct formula for "The number of races to be counted in a series
shall be calculated as 50% plus 1 (rounded down to a whole number) of the
number of
down to a whole number) of the number of
races completed for each class"
I have used (s/2 +1) but it gives incorrect results for classes that have not
sailed all the races. I'm guessing its something to do with the rounding. We
need to round down the result of s/2 but I thought that was the default set in
Sailwave.

Any advice would be hugely appreciated as I'm being hassled to get it right.
--
Kind regards
Graham Pinkney
office@stmawessailing.co.uk <mailto:office@stmawessailing.co.uk>

--
Kind regards
Graham Pinkney
office@stmawessailing.co.uk