[sage-support] Re: plot3d renders heaviside(x) but not heaviside(x-y)

2018-02-02 Thread Makoto Yamashita
Thanks, I could indeed confirm the solution!

Makoto

On Thursday, 1 February 2018 17:31:35 UTC+9, Eric Gourgoulhon wrote:
>
> A workaround is to use unit_step instead of heaviside:
>
> plot3d(unit_step(x-y),(x,-1,1),(y,-1,1))
>
> The function heaviside is known to have issues as soon as some numerical 
> evaluation is required. Another example is:
>
> numerical_integral(heaviside(x), -1, 1)
> TypeError: unable to simplify to float approximation
>
> numerical_integral(unit_step(x), -1, 1)
> (1.0, 1.1102230246251565e-14)
>
> Best wishes,
>
> Eric.
>
>

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[sage-support] Re: plot3d renders heaviside(x) but not heaviside(x-y)

2018-02-01 Thread Eric Gourgoulhon
A workaround is to use unit_step instead of heaviside:

plot3d(unit_step(x-y),(x,-1,1),(y,-1,1))

The function heaviside is known to have issues as soon as some numerical 
evaluation is required. Another example is:

numerical_integral(heaviside(x), -1, 1)
TypeError: unable to simplify to float approximation

numerical_integral(unit_step(x), -1, 1)
(1.0, 1.1102230246251565e-14)

Best wishes,

Eric.

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