nonlin4.sas

SAS for Windows统计分析系统教程,里面有源码

options nodate nonumber;
title 'Negative Exponential Growth Curve';
data nonlin4;
   input x y @@;
cards;
 20 0.57  30 0.72  40 0.81  50 0.87  60 0.91  70 0.94  80 0.95
 90 0.97 100 0.98 110 0.99 120 1.00 130 0.99 140 0.99 150 1.00
160 1.00 170 0.99 180 1.00 190 1.00 200 0.99 210 1.00
;
proc nlin best=20 method=marquardt;
   parms b0=0 to 2 by 0.5
         b1=0.01 to 0.09 by 0.01;
   model y=b0*(1-exp(-b1*x));
   der.b0=1-exp(-b1*x);
   der.b1=b0*x*exp(-b1*x);
run;