ASKSAGE: Sage Q&A Forum - Individual question feedhttp://ask.sagemath.org/questions/Q&A Forum for SageenCopyright Sage, 2010. Some rights reserved under creative commons license.Mon, 17 Sep 2012 19:16:35 -0500Precision of find_roothttp://ask.sagemath.org/question/9328/precision-of-find_root/Here is a straightforward question:
I am wondering about the precision of find_root. Looking into the documentation (I'm using Sage v. 5.0), there is a comment along with one of the examples that the "precision isn't very good on some machines." At the same time, it says that the routine converges unless it throws an error.
A post [response](http://www.mail-archive.com/sage-support@googlegroups.com/msg16187.html) from William Stein clarifies that the function is passed to SciPy which has double precision. So I'm assuming that there may be a way for more precision on some machines, but that one can always count on having at least this much.Mon, 17 Sep 2012 15:28:51 -0500http://ask.sagemath.org/question/9328/precision-of-find_root/Comment by achrzesz for <p>Here is a straightforward question:</p>
<p>I am wondering about the precision of find_root. Looking into the documentation (I'm using Sage v. 5.0), there is a comment along with one of the examples that the "precision isn't very good on some machines." At the same time, it says that the routine converges unless it throws an error. </p>
<p>A post <a href="http://www.mail-archive.com/sage-support@googlegroups.com/msg16187.html">response</a> from William Stein clarifies that the function is passed to SciPy which has double precision. So I'm assuming that there may be a way for more precision on some machines, but that one can always count on having at least this much.</p>
http://ask.sagemath.org/question/9328/precision-of-find_root/?comment=19049#post-id-19049Maybe you should consider mpmath:
sage: from mpmath import *
sage: mp.dps = 100; mp.pretty = True
sage: findroot(sin, 3)
3.141592653589793238462643383279502884197169399375105820974944592307816406286208998628034825342117068Mon, 17 Sep 2012 19:16:35 -0500http://ask.sagemath.org/question/9328/precision-of-find_root/?comment=19049#post-id-19049