nmfs-ost
[Bug]: growth discrepancy when season duration is < 1.0 (months < 12) and growth type is Gompertz-Richards
Describe the bug
A user reported unexplained growth differences when season duration is < 1.0, for example by setting a 1 season model with only 3 months that season.
Also note that when AFIX2 is not 999 , the calculated Linf from Lmax can be affected, but that is not cause of the issue above. For this, suggest investigate creation and use of AFIX_delta
To Reproduce
Take an annual model and change N months in the season. Examine the vector of length-at-age. So far, I find the expected pattern:
Expected behavior
I expected differences to be explainable by the differing number of seasons to reach the same effective age. Still doing that test.
Screenshots
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Which OS are you seeing the problem on?
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Which version of SS3 are you seeing the problem on?
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Additional Context
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Quang suggested: I think this line is what is causing the over-reduction in K: https://github.com/nmfs-ost/ss3-source-code/blob/main/SS_biofxn.tpl#L598
In my model, the K parameter is reduced by 0.25 twice with VBK_seas and seasdur. Shouldn't it be: VBK_temp2 = exp(VBK_temp * VBK_seas) - 1 ?
But Rick found that change to create wrong result for a seasons in year model.