Inserting 0 in sparse matrices without changing sparsity pattern?

3 次查看（过去 30 天）
Anders Melander
Anders Melander 2024-4-5
编辑： Bruno Luong 2024-4-5
Hello,
In my code I have very large sparse diagonal matrices, where the values of the diagonal change over time.
The code is very long, so I instead have an example of the issue profiled as seen below. If the new diagonal b contains zeros (line 17, 30% zeros), it is much slower compared to if b contains no zeros. In my own code b usually has between 5-30% zeros. My guess is this is because MATLAB reformats the sparse matrix when a zero is inserted(i.e. the element is deleted, indices are changed). Is it possible to tell MATLAB to not change the sparse matrix, but instead treat inserted zeros as any other value? By this I mean that the value 0 is actually saved in the diagonal, despite it being a sparse matrix.

请先登录，再回答此问题。

采纳的回答

Bruno Luong
Bruno Luong 2024-4-5
编辑：Bruno Luong 2024-4-5
Is it possible to tell MATLAB to not change the sparse matrix, but instead treat inserted zeros as any other value?
Short answer: No.
You can insert something that replaces 0, for example NaN or realmin and do specific treament with this value.
  1 个评论
Anders Melander
Anders Melander 2024-4-5
Yeah, I had already used realmin as a "hack", just wondered if I could have avoided it, but seems not.
Thanks for the answer!

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 Matrix Indexing 的更多信息

标签

产品


版本

R2021a

Community Treasure Hunt

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

Start Hunting!

Translated by