hsiloP

The traditional mathematician recognizes and appreciates mathematical elegance when he sees it. I propose to go one step further, and to consider elegance an essential ingredient of mathematics: if it is clumsy, it is not mathematics. (Dijkstra, 1985)

On average I probably use Google calculator at least once a day in order to perform calculations too complex for my system's built-in calculator. HsiloP is an attempt to remedy that, by packaging a powerful calculator in a streamlined interface that I can call up whenever needed and then quickly dismiss.

The interface is minimalist: the program starts out as a small green rectangle floating above your other windows. Enter numbers, and the hsiloP rectangle grows to display all the numbers in a "stack" (the picture to the left shows hsiloP running, with my desktop behind it). Each command that you enter (such as + or atan or factor) removes numbers from the bottom of the stack and replace them with a result.

This calculator uses Reverse Polish Notation (RPN). For example, to add 3 and 4, you type "3 4 +". With practice, you can perform calculations faster in RPN than you could with a normal calculator. For instance, to calculate (1 + 2) / (3 + 4) on a regular calculator, you would type something like "3 + 4 = <memory store> 1 + 2 / <memory recall> =". Using RPN, you type "1 2 + 3 4 + /". RPN also avoids the ambiguity of order of operations.

Other features of hsiloP include:

• Trigonometric functions, including an atan2 function that takes an (x, y) pair and returns an angle in the full range from -180 to 180 degrees (an ordinary atan cannot distinguish an angle from the opposite angle)
• Display of numbers in different bases: decimal, hexadecimal, binary, or octal.
• Bitwise arithmetic operators (AND, OR, XOR, and NOT)
• Full history of the commands you have typed in during a session, and the ability to scroll back through the history or to copy it.
• Combinatorial functions, factoring, GCF and LCM, and much more.

hsiloP is free, and open source.