Add a data field to track the germination percentage of a particular
variety. This would be different than the "fudge factor" as currently
implemented. As noted by StriderSnowbear (Jim), if you assume that the
fudge factor is tied to germination percentage, then the calculation is wrong:
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A note on the fudge factor calculation. If you want to actually calculate
the germination percentage accurately you will have to switch to the proper
mathematical formula. The one you are using is not correct. Your
automatic fudge factor is 20% in the settings menu, but the number of
transplants that the user is told to start actually is calculated as a 83%
germination vice the 80% germination indicated by the use of the 20 factor.
This mistake is also present in the Market Farm Forms by Rosenweig, so
don't feel bad.
Example:
you need 1000 transplants
Germination % is 80%
Your formula is the following:
P * (1+G/100) = X
where P is the number of seeds to plant
G is the fudge factor in integer value vice in %germination
X is the number of transplants
Your result: (1000) * 1.2 = 1200 seeds to start to get 1000 plants
but the actual number of plants you will get is this 1200 * (.80) = 960
transplants (you are short 40 transplants) as your formula calculates an
83% germination vice the 80% desired. The effect of this error gets very
large as one heads toward 10's of thousands of transplants and/or the
germination percentage is a low number (say 75% vice 95%).
The correct formula is the following:
X = P/G
where X is the number of seeds to plant
P is the number of transplants needed
G is the germination percentage in decimal form
X = (1000)/(.80)
= 1250 seeds to start
Original issue reported on code.google.com by cropplan...@gmail.com on 24 Jan 2009 at 4:13
Original issue reported on code.google.com by
cropplan...@gmail.comon 24 Jan 2009 at 4:13