1 | | How is a scalar field implemented which is split into different expressions in one particular chart? |

2 | | |

3 | | 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 |

4 | | {{{ |

5 | | f = M.scalar_field( unit_step(x + 1)*unit_step(1 - x)*(1 - abs(x)) ) |

6 | | }}} |

7 | | (see https://trac.sagemath.org/ticket/28519#comment:46). |

8 | | |

9 | | This solution is quite unhandy and becomes even more so for more complicated scalar fields. |

10 | | |

11 | | How is a scalar field implemented which is split into different expressions in one particular chart? |

| 1 | How is a scalar field implemented which is piecewisely defined with different expressions in one particular chart? |