2016-10-05 21:50:40 +0100 | received badge | ● Famous Question (source) |

2013-10-23 22:23:53 +0100 | received badge | ● Notable Question (source) |

2013-05-30 05:21:21 +0100 | received badge | ● Popular Question (source) |

2012-10-05 03:05:06 +0100 | received badge | ● Scholar (source) |

2012-10-05 03:05:06 +0100 | marked best answer | Piece-wise functions and plotting It seems that this version does not ignore the x*y case: Lambda is not necessary: |

2012-10-05 03:04:39 +0100 | commented answer | Piece-wise functions and plotting Ah, thanks!... In my code, I had some nested transformations going on, so I didn't pass just the function handle. Now this works, unfortunately, it takes me back to the very poor performance which makes it impractical to put it in an @interact environment |

2012-10-03 10:06:31 +0100 | commented question | Piece-wise functions and plotting Also, I just found out that Sage has the kronecker_delta function, so one could rewrite the above example as a product of two pieces, however, in my case I actually have three pieces and I would still need to find an appropriate transformation to map the pieces to non-overlapping conditions where the delta function would be 1 for exactly one of them. While possible, this is really not elegant. Any other thoughts? |

2012-10-03 10:06:23 +0100 | commented question | Piece-wise functions and plotting Yes, for one-dimensional piecewise functions that would work, but for two-dimensional or more, it would not, I am afraid. |

2012-10-03 09:44:10 +0100 | commented answer | Piece-wise functions and plotting This is a good answer in that it works, the problem now is about efficiency. If I do this with my actual function (which is a bit more complicated that the one in the example) then it takes 30 seconds to render. If I try to get fancy and make: P = lambda x,y: F(x,y); p=contour_plot( P(x,y), (x,0,1), (y,0,1) ); p.show(); Now it doesn't work again! |

2012-10-02 11:25:36 +0100 | received badge | ● Supporter (source) |

2012-10-02 11:20:42 +0100 | asked a question | Piece-wise functions and plotting Hi, I have a piece-wise defined function that I want to plot (and potentially do other symbolic stuff with) and I was wondering how to do this. The problem is that I am defining my function as a Python function: def F(x,y): if( x <= y ): return x*y return x+y So I am gluing together two pieces, and I would like to be able to do (x,y) = var('x,y') contour_plot( F(x,y), (x,0,1), (y,0,1) ) But the problem is that this only plots the second part. This occurs because x <= y evaluates as false (they are variables) and F(x,y) is always evaluated as x+y. In Mathematica there is the F(x,y) = delta( x<=y ) * (x*y) + delta( x>y ) * (x+y) But as it is, I think there is no way to do this. Is there? Thanks a lot for your help, Edgar |

Copyright Sage, 2010. Some rights reserved under creative commons license. Content on this site is licensed under a Creative Commons Attribution Share Alike 3.0 license.