Mike Hansen schrieb:
On Sun, Apr 11, 2010 at 10:01 AM, bb <bblo...@arcor.de> wrote:
Tnx for helping. I did some more experimentation. I dont want to bother you,
but if you have some time and some pation I would be thankfull for one more
explanation. Your tip works as expected, but if I use the method n() I still
get 53 bit of significant bits??? (see last expression of the snippet.)
I argue, that the parameter of n() is set elsewhere in another Variable than
RealNumber?
Yes, in the code for n, we have the following:
if prec is None:
if digits is None:
prec = 53
else:
prec = int((digits+1) * 3.32192) + 1
so it just defaults to 53 if nothing is passed in. The RealNumber =
RealField(137) just changes the precision for floating point literals
entered on the command line.
--Mike
Tnx for clearing that n()-question!
In an earlier posting (I am always thankful for any help!) you wrote:
One could do a little work to get Sage's interval arithmetic to do
something similar. Would be an interesting experiment.
I found an internet page about that topic concerning MPFR from 2/5/2006:
http://www.ma.utexas.edu/users/kschalm/mpfr-in-sage.html
(MPFR seems to be very broadly used by different Progs under GNU Lesser
GPL. Added is a list of related software.)
There are used some Sage-examples with a strange line-numbering with
underscores? May be that is an outdated Sage-Version? Actual versions do
not do any line numbering.
I did not find any evidence that MPFR or MAPM is included in Sage? I do
not understand if MPFR is compiled with Sage in this examples on that
page? I cannot find any evidence that MPFR is loaded?
In an extension of the floating point issue I am actually interested in:
I found a list of libs to support floating point arithmetics that are
not in the list of included libs to Sage. I found some examples to
include tools with a CLI via http in the documentatin. I did not find
hints how to include C/C++ or other language libs to Sage? (To clear
that statement: The fact I could not find it does not mean it is not
documented in some place!)
Again - please ignore my boring question if you feel bothered - I can
understand that! With yor response you opened a door for floting point
questions.
Tnx anyway - regards BB
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