50 digits precision handheld calculator is it achievable or not?

[Joe Horn]

It's been available for many years. It's called the HP 50g with the free LongFloat library installed. LongFloat lets you specify how many digits of precision you want, up to 9999 (really!) and it gives you new functions which use that precision, with guaranteed accuracy. It brilliantly uses the "long real" object type which HP built into the 50g and then never got around to supporting. (N.B. its header is 0263A, not 02955 which is the "extended real" type which only has 15-digit mantissas).

50-digit arithmetic with the LongFloat library is very fast. 50 digits times 50 digits takes 0.076 seconds. More digits takes longer. For example, finding 500 digits of the square root of 2 takes 2 seconds.

If you want a calculator that does 50 digit math, but you don't want to bother installing software on it, I'd be happy to install LongFloat in a 50g and sell it to you. ;-)

The LongFloat library functions are fully programmable. Accuracy is both globally and locally programmable. The functions include:

• Add, subtract, multiply, divide
• Square root, Fast Integer Part of Square Root, Square
• 1/x, -x, |x|, sign(x)
• IP, FP
• y^x, e^x, ln, ln(x+1), Gamma
• sin, cos, tan, and their inverses & hyperbolic versions
• real<>complex, conjugate, LongFloat i, LongFloat pi
• LongFloat<>Normal real
• Split LongFloat into mantissa and exponent
• Programming test functions (equal, not equal, less than, etc)
• LongFloat<>Continued Fraction (!!!)
• Unit support
• Matrix support, CON, IDN, DOT, TRN, DET
• LongFloat root finder
• Interval math support
• PSLQ (!!!)
• 5 input/output modes: Std, Floor, Ceil, Trunc, and Interval