Warning message

nadia · Post by **nadia** » Mon Nov 15, 2010 10:25 pm

Hi,

Why there is a message said that "warning, at 2010.25 above- fertiliser lookup computing- effects of fertiliser on yield" when I run the model?

Is it because of the error with the fertiliser lookup?

Thank you,

Regards,
nadia

Post by **Administrator** » Mon Nov 15, 2010 11:34 pm

Have a look at the x bounds on your lookup, and see if the value you are looking up falls outside this.

nadia · Post by **nadia** » Tue Nov 16, 2010 6:59 am

Actually I want to see at what amount of fertiliser that we have to add in order to get maximum yield. This is because the amount of fertiliser subsidy provided by the government is fixed and not enough. Therefore, farmers have to buy extra fertiliser in order to get maximum amount of yield. My equations are as follow:

yield= max yield*effects of fertiliser

effects of fertiliser on yield= fertiliser lookup ( fraction of fertiliser)

Fraction of fertiliser = (fertiliser subsidy+extra fertiliser)/recommended rate of fertiliser

My reference point is (1,1) which is the x axis will be amount of fertiliser and y axis will be yield.

x axis (1)=amount of fertiliser used must be same with the recommended rate of fertiliser

y axis (1)=max yield which is 10

Now I just put the maximum range is only at (1,1) because I only to see at what amount of extra fertiliser must be bought in order to get max yield. But this warning msg appear. Is that mean I have to put the range greater than 1?

Thank you.

Post by **Administrator** » Tue Nov 16, 2010 7:59 am

Have a look at the values "fraction of fertiliser" takes. If it's greater than 1, then that's where the warning is coming from.

nadia · Post by **nadia** » Tue Nov 16, 2010 8:57 am

Is that means when the fraction is greater than 1 the model has error?

Thank you.

Post by **Administrator** » Tue Nov 16, 2010 9:12 am

Only you will know if the model has an error.

Can "fraction of fertiliser" be larger than 1?

Post by **tomfid** » Tue Nov 16, 2010 11:12 pm

In other words, this error is really just a warning. If it's OK that your input sometimes exceeds the bounds of the lookup (which I think makes sense in this case), then you can ignore it.

Tom

nadia · Post by **nadia** » Thu Nov 18, 2010 2:34 am

hi,

Yes, this fraction can be greater than 1. Thank you everybody for your opinion and suggestions.

Regards,
Nadia