Opened 12 years ago

Last modified 6 years ago

## #11225 new defect

# improve piecewise plotting — at Version 3

Reported by: | Karl-Dieter Crisman | Owned by: | jason, was |
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Priority: | major | Milestone: | sage-7.3 |

Component: | graphics | Keywords: | piecewise |

Cc: | David Joyner, Jason Grout, Robert Pollak, Karl-Dieter Crisman, Volker Braun, Samuel Lelièvre, Matthias Köppe, Eviatar Bach, Ralf Stephan | Merged in: | |

Authors: | Reviewers: | ||

Report Upstream: | N/A | Work issues: | |

Branch: | Commit: | ||

Dependencies: | Stopgaps: |

### Description (last modified by )

Until we actually totally rewrite piecewise functions, we should improve some things.

For concreteness, here is one thing that should work but doesn't. I'm sure there are more - add to this list, and then whatever isn't fixed in this ticket can be moved to another ticket. I just want to make sure they're listed in one place, not ten tickets.

List:

- plotting more than one
sage: f = Piecewise([[(0,1),x^3], [(1,2),x^2]], x) sage: plot([f,x^3],(x,0,2))

- plotting a product of a piecewise with a symbolic (well, the problem is multiplying the two, but still worth putting here - see this sage-support thread)
- Maybe unify with
`plot_step_function`

, which currently is sort of its own thing? - In this example:
sage: zero_func(x)=0 sage: g = Piecewise([[(-1000,1),zero_func],[(1,1000),(x-1)^3]],x) sage: G = g.plot() sage: G.show(xmin=-5,xmax=5,ymax=100) sage: g(1) 0

- You can use oo (infinity) for endpoints, but then the plot code for Piecewise gets screwed up.
- You can try putting in zero instead of defining this new zero function, but then g(1) and g(-1) etc. won't work.
- You can try using extend_by_zero to make the zero part, but it gives the same problem.
- You can plot without xmin and xmax, but that gives the whole function.
- You can plot without ymax, but that gives the range further out than you want.
- You can try plot(g), but that turns out to uncover a very strange error that may or may not be a bug.

### Change History (3)

### comment:1 Changed 12 years ago by

Description: | modified (diff) |
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### comment:2 Changed 12 years ago by

Description: | modified (diff) |
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### comment:3 Changed 11 years ago by

Description: | modified (diff) |
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