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| # | |
| # Linux-DAYLOC-pred.R, 19 Apr 20 | |
| # Data from: | |
| # The {Linux} Kernel as a Case Study in Software Evolution | |
| # Ayelet Israeli and Dror G. Feitelson | |
| # | |
| # Example from: | |
| # Evidence-based Software Engineering: based on the publicly available data | |
| # Derek M. Jones | |
| # | |
| # TAG Linux_evolution LOC_evolution | |
| source("ESEUR_config.r") | |
| pal_col=rainbow(3) | |
| # Lines of code in each release | |
| ll=read.csv(paste0(ESEUR_dir, "regression/Linux-LOC.csv.xz"), as.is=TRUE) | |
| # Data of each release | |
| ld=read.csv(paste0(ESEUR_dir, "regression/Linux-days.csv.xz"), as.is=TRUE) | |
| loc_date=merge(ll, ld) | |
| # Add column giving number of days since first release | |
| loc_date$Release_date=as.Date(loc_date$Release_date, format="%d-%b-%Y") | |
| start.date=loc_date$Release_date[1] | |
| loc_date$Number_days=as.integer(difftime(loc_date$Release_date, | |
| start.date, | |
| units="days")) | |
| # Order by days since first release | |
| ld_ordered=loc_date[order(loc_date$Number_days), ] | |
| # What is the latest version | |
| n_Version=numeric_version(ld_ordered$Version) | |
| # cummax does not work for numeric_version, so we | |
| # have to track the latest version | |
| greatest_version <<- n_Version[1] | |
| keep_version=sapply(2:nrow(ld_ordered), | |
| function(X) | |
| { | |
| if (n_Version[X] > greatest_version) | |
| { | |
| greatest_version <<- n_Version[X] | |
| return(TRUE) | |
| } | |
| return(FALSE) | |
| }) | |
| latest_version=ld_ordered[c(TRUE, keep_version), ] | |
| plot_conf_int=function(mod, x) | |
| { | |
| # linear model with confidence intervals plotted | |
| prd=predict(mod, newdata=list(Number_days=x), se.fit=TRUE) | |
| summary(prd$fit) | |
| lines(x, prd$fit-1.96*prd$se.fit, col=pal_col[1], lty=2) | |
| lines(x, prd$fit+1.96*prd$se.fit, col=pal_col[1], lty=2) | |
| } | |
| latest_version$MLOC=latest_version$LOC/1e6 | |
| y_lim=c(1, max(latest_version$MLOC)) | |
| m3=glm(MLOC ~ Number_days+I(Number_days^2)+I(Number_days^3), data=latest_version) | |
| the_future=3000:7500 | |
| future_range=range(the_future) | |
| plot(latest_version$Number_days, latest_version$MLOC, col=pal_col[2], | |
| xaxs="i", yaxs="i", | |
| xlim=future_range, ylim=y_lim, | |
| xlab="Days", ylab="Linux kernel size (MLOC)\n") | |
| y=predict(m3, newdata=list(Number_days=the_future)) | |
| lines(the_future, y, col=pal_col[1]) | |
| plot_conf_int(m3, the_future) | |
| lines(c(max(latest_version$Number_days), max(latest_version$Number_days)), | |
| c(0, max(latest_version$MLOC)), col=pal_col[3]) | |