Hello. I have been using proc nlin to fit a pre-determined model to a set of value with relative success using the following line of code:
data example; input Notch Rate; datalines; 1 0.101750388 2 0.02797293 3 0.007380199 4 0.003547882 5 0.002219785 6 0.000631796 7 0.000507642 8 0.000361024 9 0.000105668 10 0.000315689 11 . 12 . 13 . 14 . 15 . 16 . ; run; proc nlin data = example; parameters alpha = 0 beta = 0; model Rate = alpha * exp (beta * Notch); output out = exponential predicted = pred_exp sse = sse_exp; run; data exponential; set exponential; format pred_exp Rate percent10.4; run;
However, as I get further, I need the fitting procedure to use only inputs to the last non-missing value (e.g. in this particular dataset, minimize the sum of squared errors of only up to first 10 observations (Notch = 10), but I also want to generalize the code to use on other datasets).
I really appreciate your help.
Hello @Minh2710,
You can exclude observations with missing Rate values by means of a WHERE statement:
proc nlin data = example; where n(rate); ...
But PROC NLIN doesn't use those observations anyway in the process of estimating the parameters, see these lines in the output table "Estimation Summary" (obtained without the WHERE statement):
Observations Read 16 Observations Used 10 Observations Missing 6
So the WHERE statement doesn't change the model.
Hello @Minh2710,
You can exclude observations with missing Rate values by means of a WHERE statement:
proc nlin data = example; where n(rate); ...
But PROC NLIN doesn't use those observations anyway in the process of estimating the parameters, see these lines in the output table "Estimation Summary" (obtained without the WHERE statement):
Observations Read 16 Observations Used 10 Observations Missing 6
So the WHERE statement doesn't change the model.
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