Hacker News Reader

Comment by mintplant | Hacker News Reader

Any recommendations for a good RPN calculator on Linux?

I generally just use dc on the command line. Pretty bare bones, but gets the job done.

M-x calc in Emacs is a very full-featured RPN calculator.

On Android, I use Droid48, a great HP48 emulator: https://play.google.com/store/apps/details?id=org.ab.x48 ; I also have RealCalc (https://play.google.com/store/apps/details?id=uk.co.nickfine...) installed, which I figured I'd use more due to the bigger buttons by default, but I still reach for Droid48 most often.

M-x calc is pretty awesome. I had no idea it was there.. (M-x tetris I had heard of)

I use dc and bc on the command line. Some people have chided me saying the command line calculators aren't always accurate and are buggy, but I haven't seen any problems.

Really? I haven't heard of any bugs in the command line calculators. Do you know what kinds of bugs they were talking about? One thing to note is that they use arbitrary-precision decimal arithmetic (well, base-100 arithmetic internally, but that's equivalent), rather than fixed precision binary floating point arithmetic, so that may surprise some people (though it also reduces surprise for those who expect decimal arithmetic).

Interesting tidbit, it seems that dc is the oldest language on Unix; it was ported before even an assembler was. (https://en.wikipedia.org/wiki/Dc_%28computer_program%29#Hist...)

I did some digging. it was in this thread in a comment about bc and exponents (although I can't use a non rpn calculator on computers I just tend to type the formulas in):

https://news.ycombinator.com/item?id=5054618

a couple of replies to my comment there about exponents. specifically.

"bc is a pretty misleading calculator, without specifying rounding it thinks 2^(40/1.5) is 67108864.

It's not even close.

If you trust your finances to that, you could get in trouble. "

Ah, thanks for digging that up. I was not aware that they didn't support fractions in exponents; I don't think I had ever tried them for that. Luckily they do give warnings, though only if you have already set the precision (via "bc -l" or something like "10 k" in dc).

Sadly, since dc doesn't have a math library, it looks like you can't use the "e" function workaround unless you implement it yourself.

M-x calc in emacs

I use galculator quite regularly, it has a pretty decent RPN mode.

forth

Reply on news.ycombinator.com