Screen brightness after suspend in Ubuntu

Many laptops have their screens dimmed after returning from “suspend” and cannot get back to their original brightness. The bug hasn’t been fixed for 3 years. A fix is provided in the bug report by putting something like the following in /etc/rc.local:

<pre class="src src-sh"><span style="color: #eedd82;">brt</span>=<span style="color: #fa8072;">`cat /sys/devices/virtual/backlight/acpi_video0/brightness`</span>

abrt=cat /sys/devices/virtual/backlight/acpi_video0/actual_brightness if (( $brt != $abrt )) ; then echo $abrt > /sys/devices/virtual/backlight/acpi_video0/brightness fi

Use the following

find /sys/ -iname 'bright'

to see if you need to change the exact path to the files.

Better decision tree graphics for rpart via party and partykit

I’ve been using Graphviz to create better decision tree graphics “by hand” for rpart objects created in R (final tree). I stumbled on this post that shows how one could convert an rpart object to a party project via the as.party function in partykit to utilize the plot functions in party. It looks quite nice.

I might have to do additional hacking as I like to display the node size and percentage of success in every node. For example, in rpart, I do something like

## rpartObj created from rpart
textRpartCustom <- 
{
    nclass <- (ncol(yval) - 1L)/2
    group <- yval[, 1L]
    counts <- yval[, 1L + (1L:nclass)]
    if (!is.null(ylevel)) 
        group <- ylevel[group]
    temp1 <- rpart:::formatg(counts, digits)
    if (nclass > 1) {
        ## temp1 <- apply(matrix(temp1, ncol = nclass), 1, paste, 
        ##     collapse = "/")
      temp1 <- matrix(as.numeric(temp1), ncol=nclass)
      ##temp1 <- paste("p=", round(temp1[, 2] / apply(temp1, 1, sum)100, 1), "%", "; N=", apply(temp1, 1, sum), sep="")
      temp1 <- paste("", round(temp1[, 2] / apply(temp1, 1, sum)100, 1), "%", "; ", apply(temp1, 1, sum), sep="") 
    }
    if (use.n) {
        out <- paste(format(group, justify = "left"), "\n", temp1, 
            sep = "")
    }
    else {
        out <- format(group, justify = "left")
    }
    return(out)
}

rpartObj$functions$text <- textRpartCustom plot(rpartObj) text(rpartObj)

to get these information to display for a classification fit.

Enable root account in Ubuntu?

After my recent experience with broken su and sudo commands in a failed system upgrade, I realized that although disabling the root account has many advantages, one of the disadvantage is that I can’t login as root in the terminal when I’m physically in front of the system. This is a major issue if su, sudo, and passwd binaries are broken somehow. Luckily, chroot was there to the rescue for me. Now, I contemplate whether I should enable the root account on my systems…