Permalink
Cannot retrieve contributors at this time
| # | |
| # Elliott_77.R, 17 May 20 | |
| # Data from: | |
| # Life Cycle Planning for a Large Mix of Commercial Systems | |
| # I. R. Elliott | |
| # | |
| # Example from: | |
| # Evidence-based Software Engineering: based on the publicly available data | |
| # Derek M. Jones | |
| # | |
| # TAG system_lifetime project_staffing system_rewrite | |
| source("ESEUR_config.r") | |
| # The igraph package (which might be loaded when building the book) | |
| # contains functions found in gnm. The treemap package might also have | |
| # been loaded (as might phangorn), and its 'load' of igraph cannot be | |
| # undone without first unloading treemap! | |
| unloadNamespace("FrF2") | |
| unloadNamespace("treemap") | |
| unloadNamespace("phangorn") | |
| unloadNamespace("igraph") | |
| library("gnm") | |
| pal_col=rainbow(2) | |
| staff=read.csv(paste0(ESEUR_dir, "projects/Elliott_77.csv.xz"), as.is=TRUE) | |
| peak=subset(staff, P_A == "Peak") | |
| average=subset(staff, P_A == "Average") | |
| plot(average$Years, average$Staff, log="y", col=pal_col[2], | |
| ylim=c(50, 210), | |
| xlab="Lifetime (years)", ylab="Staff\n") | |
| aver_mod=gnm(Staff ~ instances(Mult(1, Exp(Years)), 2)-1, | |
| data=average, verbose=FALSE, trace=FALSE, | |
| start=c(300, -1, 100, -0.1)) | |
| summary(aver_mod) | |
| exp_coef=as.numeric(coef(aver_mod)) | |
| t=predict(aver_mod) | |
| lines(average$Years, t, col=pal_col[1]) | |
| # lines(average$Years, exp_coef[1]*exp(exp_coef[2]*average$Years), col=pal_col[1]) | |
| # lines(average$Years, exp_coef[3]*exp(exp_coef[4]*average$Years), col=pal_col[3]) | |
| # # The models constant offset has a big impact | |
| # me_mod=mexpfit(average$Years, average$Staff, p0=c(-0.9, -0.1)) | |
| # print(me_mod) | |
| # peak_mod=gnm(Staff ~ instances(Mult(1, Exp(Years)), 2)-1, | |
| # data=peak, verbose=TRUE, trace=TRUE, | |
| # start=c(300, -1, 100, -0.1)) | |
| # summary(peak_mod) | |