Working with more than 16 digits?



Three things:

(1) The value of fpprec mysteriously affects the number of displayed 
digits 
for double floats.

(2) Doing ev(e, numer) evaluates 'e 'to a double (or least it does 
sometimes).

(3) To evaluate to a big float, use the function 'bfloat'

(%i1) bfloat(%pi), fpprec : 50;
(%o1)        3.1415926535897932384626433832795028841971693993751B0

Barton




Albert Reiner 
Sent by: maxima-admin@math.utexas.edu
01/31/2005 09:25 AM

 
        To:     Maxima mailing list 
        cc: 
        Subject:        [Maxima] Working with more than 16 digits?


Hi,

the documentation of FPPREC:

,----
|  - Variable: FPPREC
|      default: [16] - Floating Point PRECision.  Can be set to an
|      integer representing the desired precision.
`----

seems to suggest that setting it to something higher than 16 would
result in a higher working precision than default double precision
numbers.  However, while

,----
| block([fpprec: 2], print(ev(%pi, numer))) $
| 
| 3.14 
`----

...

,----
| block([fpprec: 14], print(ev(%pi, numer))) $
| 
| 3.14159265358979 
`----

,----
| block([fpprec: 15], print(ev(%pi, numer))) $
| 
| 3.141592653589793 
`----

all work more or less as expected, a higher fpprec does not print out
more digits as, e.g., N[Pi, 500] does in Mathematica or something like
N(Pi, 500); does in yacas.

Is there a simple way to get, say, the first 25 digits of pi in
Maxima?

Thanks in advance,

Albert.

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