清空筛选条件
清空筛选条件

solving linear equations in a loop

2 次查看（过去 30 天）
Krzysztof
Krzysztof 2014-3-21
编辑： Matt J 2014-3-21
The documentation for inv says:
A frequent misuse of inv arises when solving the system of linear equations Ax = b. One way to solve this is with x = inv(A)*b. A better way, from both an execution time and numerical accuracy standpoint, is to use the matrix division operator x = A\b.
The above taken for granted, is it nevertheless reasonable to precalculate invA = inv(A) in front of a loop containing (A\Xi), especially one that necessarily sequential?

请先登录，再回答此问题。

采纳的回答

Matt J
Matt J 2014-3-21
编辑：Matt J 2014-3-21
No. Make the different Xi the columns of matrix, X and just do A\X.
  2 个评论
Krzysztof
Krzysztof 2014-3-21
In case you did not have time to have a look at the algorithm: X(i+1) depends on A\X(i).
Matt J
Matt J 2014-3-21
编辑：Matt J 2014-3-21
Probably better, then to pre-compute the LU decomposition
[L,U]=lu(A);
and then solve the system for each Xi using (U\(L\Xi)). You might improve things still further with an L,U,P decomposition.

请先登录，再进行评论。

更多回答（0 个）

类别

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

标签

产品

Community Treasure Hunt

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

Start Hunting!

Translated by