关于coda包gelman.plot命令图例调整与隐藏的技术咨询

Great question! Let's break down how to address your two needs for the gelman.plot() function from the coda package: resizing the legend for the median and 97.5% confidence limit, or hiding it entirely.

Resizing the Legend #

The gelman.plot() function doesn't have a built-in parameter to adjust legend size directly (since it relies on base R's plotting system). But you can easily override the default legend with a custom one where you control the size using the cex argument:

1. First, generate your Gelman plot as usual (we'll use sample data from the coda package for demonstration):

library(coda)
data(line) # Sample MCMC object included with coda
gelman.plot(line)

2. Next, call the legend() function to replace the default legend. Make sure to match the original legend's position, colors, and line types, then use cex to set your preferred size (values >1 enlarge the legend, <1 shrink it):

legend("topright", 
       legend = c("Median", "97.5% CL"),
       col = c("black", "gray"),
       lty = c(1, 2),
       cex = 1.5) # Tweak this number to get your desired size

This will overwrite the original legend with one scaled exactly how you want it.

Hiding the Legend Entirely #

This is even simpler—gelman.plot() has a built-in legend parameter that you can set to FALSE to suppress the legend completely:

gelman.plot(your_mcmc_object, legend = FALSE)

Just replace your_mcmc_object with your actual MCMC dataset, and the plot will render without any legend.

内容的提问来源于stack exchange，提问作者Sara Salvador