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Extended precision library - G.E. - 05-25-2019 10:27 AM
This is a library of functions to allow unlimited floating point precision for all arithmetic and most transcendental functions on the Prime.
Explanations can be found (in French...) in the 11th issue of the french journal "La Gazette des Pocketicaires" available for free download at :
http://silicium.org/site/index.php/telechargements/category/4-la-gazette-des-pocketicaires.
Very shortly, all function names start with the letter x.
To start type xinit(7) for example where 7 is the number of slices of 6 digits that you want to have available.
Here 7 means you calculate on 42 digits.
Values are stored as lists.
To convert from/to the readable representation which is a string, you use two functions.
Example :
xtof("1256.23589") returns a list
xtostr(that list) gives you back the string "1256.23589".
Then you can use the lists created this way to calculate, see the examples in the test file attached.
Feedback welcome.
RE: Extended precision library - StephenG1CMZ - 05-25-2019 10:15 PM
Just an idea on the user interface
I am wondering whether users might find it more natural to specify the number of digits they want to use, rather than the number of slices.
As xinit(42) seems more intuitive than xinit(7) when the user wants 42 digits.
RE: Extended precision library - G.E. - 05-26-2019 04:18 PM
Hello,
Sure good idea, that's fairly simple.
List of changes to do :
- add an xversion function
- use Newton methode for division
- change xinit so that it takes a number of digits and not slices
- add cos, asin, acos
- normalize angles as input to sin/cos/tan
- (hard) fix precision issues in cordic functions
G.E.
RE: Extended precision library - erazor - 04-08-2021 07:03 AM
Maybe I'm doing something wrong?
xinit(5) -> 5
xtostr(xlog(xtof("0.01"))) -> "-999997697417.20959.....
while
LN(0.01) -> -4.6051....
RE: Extended precision library - robmio - 08-22-2021 08:38 PM
Hello, I find it difficult to make ”Extended Precision Library” work.
In fact, after having transferred the three programs in the HP PRIME virtual calculator, ie "multiprecision", "mutiprecision2" and "testmulti", and after having opened them (shift program, EDIT), I get an error message:
1) In “multiprecision”, I get an error on line 265;
2) In “multiprecision2”, I get an error on line 170;
3) In “testmulti”, I get an error on line 108;
Where am I doing wrong?
Yours sincerely, Roberto Mioni