add a function for the derivative of ceil and floor

[burcin]

We should define a new symbolic function for the derivative of ceil or floor.

In Maple:

> diff(floor(x),x);
                                  floor(1, x)
> diff(floor(x),x,x);
                                  floor(1, x)
> diff(ceil(x),x,x); 
                                  floor(1, x)
> eval(diff(ceil(x),x,x),x=1.5);
                                       0
> eval(diff(ceil(x),x,x),x=0);  
Error, (in floor) floor is not differentiable at integers

CC: @sagetrac-ktkohl @rwst @kcrisman @pelegm

Component: symbolics

Keywords: sd35.5

Author: Karen Kohl

Branch/Commit: u/ktkohl/add_a_function_for_the_derivative_of_ceil_and_floor @ 8013b9f

Issue created by migration from https://trac.sagemath.org/ticket/9874

[sagetrac-ktkohl]

Changed keywords from none to sd35.5

[sagetrac-ktkohl]

Author: ktkohl

[sagetrac-ktkohl]

Branch: u/ktkohl/add_a_function_for_the_derivative_of_ceil_and_floor

[sagetrac-ktkohl]

comment:8

These give the right answer but also a runtime error:

sage: floor(x).derivative().subs(x=1.5)
Exception RuntimeError: 'maximum recursion depth exceeded while calling a Python object' in 'sage.structure.parent.good_as_coerce_domain' ignored
0
sage: ceil(x).derivative().subs(x=1.5)
Exception RuntimeError: 'maximum recursion depth exceeded while calling a Python object' in 'sage.structure.parent.good_as_coerce_domain' ignored
0

---

New commits:

8013b9f

Added ceiling and floor functions to allow 2nd argument for derivative.

[sagetrac-ktkohl]

Commit: 8013b9f

[sagetrac-ktkohl]

Changed author from ktkohl to Karen Kohl

[rwst]

comment:11

Just a quick note that there are empty examples and tests fields but you probably know that.