#3955: make find_minimum_on_interval use _fast_float_
-------------------------------+--------------------------------------------
       Reporter:  was          |         Owner:  burcin      
           Type:  enhancement  |        Status:  needs_review
       Priority:  major        |     Milestone:  sage-5.1    
      Component:  calculus     |    Resolution:              
       Keywords:               |   Work issues:              
Report Upstream:  N/A          |     Reviewers:              
        Authors:               |     Merged in:              
   Dependencies:  #2607        |      Stopgaps:              
-------------------------------+--------------------------------------------
Changes (by aginiewicz):

  * dependencies:  => #2607


Old description:

> {{{
>

> On Tue, Aug 26, 2008 at 2:07 AM, Stan Schymanski <[email protected]>
> wrote:
> >
> > Dear William,
> >
> > On Aug 25, 6:48 pm, "William Stein" <[email protected]> wrote:
> >
> >> If you call _fast_float_ as illustrated below on your functions,
> find_* will
> >> work, and also be much much faster:
> >>
> >> sage: find_maximum_on_interval((-x^2)._fast_float_(x),-1,1)
> >> (-7.7037197775489434e-34, -2.77555756156e-17)
> >> sage: find_minimum_on_interval((-x^2)._fast_float_(x),-1,1)
> >> (-0.99999992595132459, -0.999999962976)
> >>
> >> find_* doesn't do this already since (1) _fast_float_ was written
> >> after find_*, and (2) nobody has had the time to change find_*
> >> to use _fast_float_.
> >
> > That's amazing, thank you! I didn't find any information about the
> > _fast_float_. Can it be used for other purposes, too?
>
> Yes.  It takes any polynomial or symbolic expression and turns
> it into a very fast callable function that has input and output floats.
> It should get used automatically by functions like find_min* but
> we haven't pushed this through enough yet.
> }}}

New description:

 {{{


 On Tue, Aug 26, 2008 at 2:07 AM, Stan Schymanski <[email protected]>
 wrote:
 >
 > Dear William,
 >
 > On Aug 25, 6:48 pm, "William Stein" <[email protected]> wrote:
 >
 >> If you call _fast_float_ as illustrated below on your functions, find_*
 will
 >> work, and also be much much faster:
 >>
 >> sage: find_maximum_on_interval((-x^2)._fast_float_(x),-1,1)
 >> (-7.7037197775489434e-34, -2.77555756156e-17)
 >> sage: find_minimum_on_interval((-x^2)._fast_float_(x),-1,1)
 >> (-0.99999992595132459, -0.999999962976)
 >>
 >> find_* doesn't do this already since (1) _fast_float_ was written
 >> after find_*, and (2) nobody has had the time to change find_*
 >> to use _fast_float_.
 >
 > That's amazing, thank you! I didn't find any information about the
 > _fast_float_. Can it be used for other purposes, too?

 Yes.  It takes any polynomial or symbolic expression and turns
 it into a very fast callable function that has input and output floats.
 It should get used automatically by functions like find_min* but
 we haven't pushed this through enough yet.
 }}}

 '''Apply:'''
  * [attachment:trac3955-find_local_maximum-ff.patch]

--

Comment:

 Due to number of inevitable changes in #2607 and fact, that's it is ready
 for review with reviewers comments fixed, I already rebased this patch on
 top of it and added it to dependencies. This patch also looks cleaner on
 top of it.

-- 
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/3955#comment:10>
Sage <http://www.sagemath.org>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica, 
and MATLAB

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