HP 19C versus HP 95C

[Valentin Albillo]

(04-22-2018 04:08 PM)Cosmo Wrote:  Which program requires so may registers and 98 steps ?

Any program which has to deal with matrices always needs as many registers as possible. Just for instance, a program can implement matrix inversion and multiplication in significantly less than 98 steps and if 30 registers are available it can deal with matrices up to 5x5 and thus invert them and solve systems of up to 5 linear equations in 5 unknowns (with a little stack juggling to be able to handle all 6x5 = 30 data and still be able to use register 0 for indirect addressing).

Further, with a different approach (triangularization instead of inversion) you can solve systems up to 7x7 with registers to spare and perhaps 8x8 might still be doable.

Apart from solving linear systems, having 30 or more registers will allow for relatively simple programs to perform polynomial least squares regression or even minimax for degrees 3, 4, and better, and the same applies to statistics. In short there are many useful algorithms that can be implemented in 98 steps or less and general enough to work with arbitrarily large datasets so the more registers the merrier.

That said, being allowed to partition available memory between program space and data space as needed (a la HP-34C) is optimal, of course.

V.
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