that book was published 1994 right? How many years has it been ? computer technology since that time has evolved. CPUs got faster since then. don't be a speed freak!

Ok, let's keep to the topic. you produce a function to compare/calculate/do floating points but that takes you how many lines of code? tools like bc and awk, which are under the single unix specs are already available in most distro and ready to use (of course don't talk about embedded systems). The fact that they are ready to use means i only take just less than 10 secs? to code up a decimal comparison statement as compared to having to reinvent the whole thing, or search, download and install your custom made function on your website to one's system. Then he has to figure out how to use your function or ponder whether they are stable enough to not have bugs in the future.
Also, not everyone who install *nix knows about your function, BUT they more or less do know about standard utilities like awk/bc. Not everyone uses the same shell. (can your function work in most shells?? ), but awk/bc are almost always there.

As already shown, the time taken to run floating point math using awk vs your function are comparable. Not even 0.010 secs. and the awk syntax is standard in every version of awk (and pretty standard across multiple languages as well). So everyone understands what < or > or <= or >= means.

On a side note, you mention that bash is good programming language, then why is it that until now, there isn't support for floating point maths? ( i am under the assumption that bash 4.0 still doesn't support floating point maths, if it does already, pls correct me.). Why is that using bash's while read loop to read big files is still so slow?

In conclusion about response time wrt to "comparing 2 numbers with decimal", it doesn't matter if you use external tools !

I think its about time we stop as its going OT.