> > >/ I am trying to fit a non linear regression model to time series data. > />/ > />/ If I do this: > />/ reg.logis = nls(myVar~SSlogis(myTime,Asym,xmid,scal)) > />/ I get this error message (translated to English from French): > />/ Erreur in nls(y ~ 1/(1 + exp((xmid - x)/scal)), data = xy, start = > />/ list(xmid = aux[1], : > />/ le pas 0.000488281 became inferior to 'minFactor' of 0.000976562 > / > If it occurs after a few iterations (was it verbose=TRUE; sorry, no docs at > hand), almost always means that there is no unique solution. Are you sure that > your data level out at 1? Or is a normalization factor needed? Try to repost > with the original data set if possible. This error message might also turn up > when the start values were totally off, so try to plot the curve and the data > with the start values. > > Setting minFactor never helped for me in that case. > > Dieter Here is the original dataset I am working on:
> myTime Time Series: Start = 0 End = 1066 Frequency = 0.0769230769230769 [1] 0 13 26 39 52 65 78 91 104 117 130 143 156 169 182 [16] 195 208 221 234 247 260 273 286 299 312 325 338 351 364 377 [31] 390 403 416 429 442 455 468 481 494 507 520 533 546 559 572 [46] 585 598 611 624 637 650 663 676 689 702 715 728 741 754 767 [61] 780 793 806 819 832 845 858 871 884 897 910 923 936 949 962 [76] 975 988 1001 1014 1027 1040 1053 1066 > > myVar Time Series: Start = 0 End = 1066 Frequency = 0.0769230769230769 [1] 59.88812 60.32571 60.76331 61.20090 61.63849 58.63085 59.25744 [8] 71.99815 54.14649 25.11732 52.28806 47.93601 38.20542 43.55031 [15] 101.35488 90.63455 79.91422 69.19390 58.47357 41.52232 48.24774 [22] 31.24054 32.98928 35.33158 15.96929 17.73995 19.65816 21.57638 [29] 23.49459 26.14397 28.92629 31.70861 35.75325 46.74069 57.72812 [36] 69.56075 41.51180 27.91007 41.16375 51.24584 60.75127 70.25670 [43] 27.28310 28.82234 30.36158 31.90082 33.44006 34.97930 36.51854 [50] 75.18015 39.08242 53.25049 21.68338 21.72782 24.50556 29.30659 [57] 27.59313 23.92532 20.25751 16.30756 49.36701 87.93636 32.38620 [64] 28.05113 23.89006 27.63523 24.84287 23.81066 35.87769 24.84182 [71] 28.53371 19.53002 13.27322 15.30672 17.34021 29.75360 19.13744 [78] 29.09236 27.75517 26.52083 19.98650 26.09178 54.22785 > ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
