How to include constraint for pdepe solution (e.g., u>0)

2 次查看（过去 30 天）
Abedeh Abd
Abedeh Abd 2016-10-3
评论： Abedeh Abd 2016-10-3
Hello, I want to solve a parabolic partial differential equation (i.e., mixed Richards' Eq): du/dt=d/dz(A(z)*du/dz+B(z)) I want to put a constraint so that all solution are greater than a constant value, c (u>c). I would be grateful if you help me.
Thanks, Abedeh

请先登录，再回答此问题。

回答（1 个）

Gareth Thomas
Gareth Thomas 2016-10-3
Piecewise function
In R2016b one can use the Piecewise function. I hope that this helps you.
  1 个评论
Abedeh Abd
Abedeh Abd 2016-10-3
Sorry! I did not get your hint. Would you please explain more. Assume I use pdepe and pdepe solve it (i.e., u). some elements of solution (u) is less than 0.05. However, I know u never is less than 0.05 in nature (physically basis). How should I define this constraint to pdepe? I do not want to manually change it using u(find(u<0.05))=0.05 after pdepe solve equation.

请先登录，再进行评论。

类别

在 Help Center 和 File Exchange 中查找有关 Mathematics 的更多信息

标签

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by