My views about Thimbleby's "new calculator" Message #20 Posted by Karl Schneider on 1 Dec 2006, 3:20 a.m., in response to message #3 by Antonio Maschio (Italy)
Hello, Antonio --
Quote:
I discovered Thimbleby works long ago, and I totally agree with him. Here's a complete list of his works about calculators:
More than a year ago, I also had read at least three of the four documents you linked, and even e-mailed Prof. Thimbleby asking if he'd like some comments. Unfortunately, I haven't yet followed through.
I agree with most of the criticisms he levied at modern mass-market calculators, which are often counter-intuitive. However, I don't endorse his concept of a new calculator user interface.
Fundamentally, the idea presented in the articles is a calculator that unravels and solves problems by combining algebra along with the function of calculation. The user specifies the variable to be solved by simply omitting it from the expression, then the calculator does the rest. The syntax is rather informal and unstructured -- prone to ambiguity and misinterpretation, I believe.
I disagree with that approach, primarily on those grounds. I would prefer instead the structure and user-friendliness of the HP-17B/HP-27S equation editor/solver: The user enters an expression with named variables if desired, then the calculator interprets and validates the expression, and subsequently provides an easy means of entering values for unknown variables and solving for the remaining one.
That solver can even perform algebra to obtain a "direct" solution if the form of the expression suggests only one primary solution. That capability was incorporated into the HP-33S' solver with a less-capable equation editor, and the solvers on all three models have the unwelcome characteristic that they must be "tricked" in order to find solutions other than the primary one.
That suggests my other objection to Thimbleby's concept: An expression might have multiple solutions for the unknown variable that lack a regular pattern, as is found with the roots of a polynomial. Which solution would his calculator find?
As mentioned by others, Thimbleby's objection to the RPN-based HP-32SII was its 4-level stack. Of course, that is not a characteristic of RPN per se, but a constraint that could easily be changed.
I have not reviewed his latest work.
- KS
Edited: 2 Dec 2006, 4:15 p.m.
|