High precision library for Prime is possible?

[Joe Horn]

Prime's CAS is pretty much a subset of Bernard Parisse's "XCAS" math software for PC's. XCAS, like most PC-based CAS software, has the feature of user-settable precision. You can tell it how many digits the floating-point results should have. Although that feature is not currently implemented in Prime, I agree with you that it would be MASSIVELY COOL if HP were to include it in a future firmware update.

Here's my Crystal Ball Wild Guess about that... According to the XCAS documentation, the user can adjust the floating-point precision by setting the control variable called "Digits" to the number of decimal places desired. So for example Digits:=20 sets XCAS to produce 20 digits. Lo and behold, Prime's CAS also has a control variable called Digits, which is displayed in CAS Settings, page 1. But it currently is ignored by the system. I have a sneaking suspicion that *IF* they ever add user-adjustable precision to Prime's CAS, then it'll be via CAS's "Digits" control variable. In fact I'll bet up to 5¢ on it.

Meanwhile, when my beloved 50g with LongFloat is not handy, I like to play with extended precision on the Prime using a trick from The Old Days of Programming: use CAS's *integer* type to fake floating point math. Thinking of ways to do floating-point math using only integers is a delightful mental exercise. For example, you can get the first 20 digits of 1234/6789 with this CAS command: iquo(1234*alog10(20),6789). Inserting the decimal point is left to you, just like in the Slide Rule days.