id summary reporter owner description type status priority milestone component resolution keywords cc merged author reviewer upstream work_issues branch commit dependencies stopgaps
28554 Scalar Field Restrictions gh-DeRhamSource "How is a scalar field implemented which is split into different expressions in one particular chart?
Take for instance a scalar field `f` on the real line with standard ""top"" chart `x`, defined via `f(x)=0 for x<-1`, `f(x)=x+1 for -1<=x<0`, `f(x)=1-x for 0<=x<1` and `f(x)=0 for x>=1`. Currently, this is solved by using
{{{
f = M.scalar_field( unit_step(x + 1)*unit_step(1 - x)*(1 - abs(x)) )
}}}
(see https://trac.sagemath.org/ticket/28519#comment:46).
This solution is quite unhandy and becomes even more so for more complicated scalar fields.
In this ticket, I try to solve this issue by adding a `set_restriction` method (similar to tensor fields) and modifying the `display` method." enhancement new major sage-9.0 geometry manifolds, scalar fields tscrim egourgoulhon N/A