#2452: [with patch, needs review] Heaviside step function, Dirac delta needed
-------------------------+--------------------------------------------------
Reporter: gfurnish | Owner: gfurnish
Type: enhancement | Status: assigned
Priority: critical | Milestone: sage-4.1
Component: symbolics | Keywords:
Reviewer: | Author:
Merged: |
-------------------------+--------------------------------------------------
Changes (by gmhossain):
* component: calculus => symbolics
Old description:
> Symbolic heaviside step function is needed for ease of plotting. Right
> now you must
>
> {{{
> sage: def u(x):
> if(x<0):
> return 0
> else:
> return 1*cos(x)
> sage: plot(u,-5,5)
> }}}
> instead of
> {{{
> plot(heaviside(t)*cos(t),t,-5,5)
> }}}
New description:
Symbolic heaviside step function is needed for ease of plotting. Right
now you must
{{{
sage: def u(x):
if(x<0):
return 0
else:
return 1*cos(x)
sage: plot(u,-5,5)
}}}
instead of
{{{
plot(heaviside(t)*cos(t),t,-5,5)
}}}
'''Update:''' Attached patch adds support for three generalized
functions: Dirac delta, Heaviside step and unit step in new pynac-based
symbolics.
The adopted convention is discussed here
http://groups.google.com/group/sage-
devel/browse_thread/thread/5f7de72642b8e568/f226acf9a6331d4d
These functions can be used in Sage like any other symbolic functions.
A specialized integration algorithm involving generalized functions is
under development and will be posted as a separate ticket.
--
Comment:
Descriptions/title are updated and a patch (sage-4.0.2) implementing Dirac
delta, Heaviside step and Unit step function is attached.
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/2452#comment:5>
Sage <http://sagemath.org/>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica,
and MATLAB
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