> On 01-01-2015, at 05:52, John Sorkin <jsor...@grecc.umaryland.edu> wrote: > > Windows 7 > > > I am running normalmixEM to fit two normal curves to my data. For some > reason, that I don't understand, the results of running the function twice, > on the same data, results in two different (although similar) sets of values. > I would expect the function run twice on the same data would give exactly the > same results! > > > I ran the program below and got the following results: > > > lambda1 mu1 lambda1 lambda2 lambda2 mu2 > 0.5030387 31.5172824 0.5030387 0.4969613 0.4969613 104.9249404 >> run2 > lambda1 mu1 lambda1 lambda2 lambda2 mu2 > 0.5030406 31.5174149 0.5030406 0.4969594 0.4969594 104.9251556 > > > > > > #Define data > John<-c(9.181 ,9.464 ,9.464 ,10.265 ,11.477 ,11.477 ,11.477 ,12.361, > 12.361 ,12.361 ,12.361 ,12.985 ,12.985 ,13.384 ,13.384 ,13.962, > 14.517 ,14.698 ,14.698 ,14.698 ,14.698 ,15.398 ,15.398 ,16.231, > 16.231 ,16.552 ,16.552 ,16.711 ,16.711 ,17.481 ,17.481 ,17.481, > 17.927 ,18.506 ,18.506 ,18.928 ,18.928 ,18.928 ,19.612 ,19.612, > 19.745 ,19.745 ,20.530 ,20.530 ,21.162 ,21.162 ,21.162 ,21.162, > 21.162 ,21.776 ,21.776 ,22.607 ,22.607 ,22.723 ,22.954 ,23.408, > 23.632 ,25.353 ,25.353 ,25.663 ,25.663 ,25.663 ,25.969 ,26.171, > 26.171 ,26.171 ,26.768 ,27.544 ,27.640 ,27.640 ,27.735 ,28.761, > 29.215 ,29.840 ,30.190 ,30.881 ,30.881 ,31.220 ,31.220 ,31.220, > 31.888 ,31.888 ,32.135 ,32.461 ,32.461 ,32.623 ,33.104 ,34.123, > 35.855 ,35.928 ,35.928 ,36.293 ,36.293 ,37.012 ,37.366 ,37.366, > 37.366 ,37.647 ,37.850 ,37.856 ,37.856 ,38.202 ,38.202 ,38.954, > 39.021 ,39.089 ,39.089 ,39.223 ,39.491 ,39.624 ,40.153 ,40.609, > 40.868 ,41.380 ,41.380 ,42.200 ,42.324 ,42.324 ,42.324 ,43.126, > 43.853 ,43.853 ,44.152 ,44.568 ,45.213 ,45.446 ,45.562 ,46.193, > 46.193 ,46.421 ,47.320 ,48.203 ,48.257 ,49.284 ,49.656 ,50.550, > 50.550 ,51.938 ,52.342 ,52.342 ,52.342 ,52.393 ,53.586 ,53.733, > 54.560 ,55.184 ,55.280 ,56.691 ,57.384 ,57.384 ,57.522 ,59.856, > 59.856 ,60.599 ,61.975 ,65.004 ,68.861 ,69.052 ,69.811 ,70.897, > 71.267 ,71.489 ,73.056 ,74.485 ,74.732 ,75.189 ,76.439 ,77.126, > 77.670 ,77.975 ,78.514 ,80.338 ,80.600 ,83.173 ,83.205 ,83.553, > 84.181 ,84.960 ,86.160 ,86.405 ,86.618 ,87.646 ,89.284 ,89.401, > 89.989 ,90.456 ,90.892 ,90.892 ,90.950 ,91.412 ,91.729 ,92.072, > 92.273 ,92.330 ,92.529 ,92.870 ,93.661 ,94.194 ,94.640 ,94.807, > 95.029 ,95.112 ,95.885 ,96.132 ,96.869 ,97.438 ,97.600 ,98.567, > 99.020 ,99.020 ,99.127 ,100.683 ,100.683 ,101.231 ,102.266 ,102.498, > 102.883 ,103.113 ,103.291 ,103.800 ,103.927 ,104.332 ,104.685 ,104.685, > 104.710 ,105.911 ,106.333 ,107.073 ,107.123 ,107.172 ,107.172 ,107.907, > 107.907 ,108.272 ,108.272 ,108.345 ,108.564 ,108.758 ,109.338 ,110.201, > 110.201 ,110.559 ,111.130 ,111.438 ,111.556 ,112.004 ,112.004 ,112.004, > 112.684 ,112.940 ,112.940 ,113.034 ,113.661 ,113.661 ,113.962 ,113.985, > 114.031 ,114.607 ,114.607 ,114.768 ,115.249 ,115.797 ,116.069 ,116.160, > 117.041 ,117.154 ,117.983 ,118.473 ,118.473 ,118.495 ,118.495 ,118.762, > 119.027 ,120.501 ,120.959 ,122.000 ,122.022 ,123.396 ,123.609 ,123.737, > 124.035 ,124.416 ,124.818 ,124.881 ,124.881 ,125.071 ,125.387 ,125.576, > 127.636 ,128.089 ,128.233 ,132.675 ,133.566 ,134.509 ,134.666 ,135.037, > 135.504 ,136.589 ,138.675 ,141.961 ,144.608 ,155.222 ,158.646 ,168.502) > > > # First run of normalmixEM > mixmdl = normalmixEM(John) > run1<-c(lambda1=mixmdl$lambda[1],mu1=mixmdl$mu[1],lambda=mixmdl$lambda,lambda2=mixmdl$lambda[2],mu2=mixmdl$mu[2]) > #Second run of normalmixEM > mixmdl = normalmixEM(John) > > > # Results are not the same! > run2<-c(lambda1=mixmdl$lambda[1],mu1=mixmdl$mu[1],lambda=mixmdl$lambda,lambda2=mixmdl$lambda[2],mu2=mixmdl$mu[2]) > run1 > run2 >
Not surprising if you read the help for normalmixEM. Starting values for three parameters (lambda, mu, sigma) are randomly generated. If you insert set.seed(<some number>) before each call of normalmixEM you will get identical results. Berend ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see 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.
