清空筛选条件
清空筛选条件

Find indexs of minimum in 4-D matrix.

7 次查看（过去 30 天）
Clément Métayer
Clément Métayer 2020-5-10
评论： Steven Lord 2020-5-10
Hi im trying to find the indexs of the minimum in a 4-D "matrix" but the usual command:
[Minimum,Index]=min(Expression,[],'all') does not work.
(here "Expression" is my function of 4 variables )
The error message tells me : Error using min
Specify 'linear' option when returning two outputs and the dimension is 'all' or a vector.
But when i specify the linear option it returns me the index 11755218 and i don't understand what it means ?
Note: the ndgrid of my function is :[phi1,phi2,phi3,phi4]=ndgrid(0:0.1:2*pi,0:0.1:2*pi,0:0.1:2*pi,0:0.1:2*pi);
Thx to the great saouls who can help me.
  1 个评论
Steven Lord
Steven Lord 2020-5-10
Walter has showed you how to get what you're looking for. But to answer your question (what 11755218 means) that is the linear index to the element whose value is returned as Minimum. See the "Indexing with a Single Index" section on this documentation page for an explanation of linear indexing.
A = reshape(1:24, [4 2 3])
A(15)
A(3, 2, 2)
Element (3, 2, 2) of A is also element 15 of A.

请先登录，再进行评论。

请先登录，再回答此问题。

采纳的回答

Walter Roberson
Walter Roberson 2020-5-10
编辑：Walter Roberson 2020-5-10
[Minimum, Index] = min(Expression, [], 'all', 'linear')
[idx{1:ndims(Expression)}] = ind2sub(size(Expression), Index);
[idx{:}]
Though perhaps what you want is instead
[Minimum, Index] = min(Expression, [], 'all', 'linear')
[phi1(Index), phi2(Index), phi3(Index), phi4(Index)]
  1 个评论
Clément Métayer
Clément Métayer 2020-5-10
Thanks you so much for your answer it works well !!!
Yes the second is the rgiht one that i was looking for.
Thx walter

请先登录，再进行评论。

更多回答（1 个）

Gifari Zulkarnaen
Gifari Zulkarnaen 2020-5-10
Maybe linear means the index ordered in from high dimension to one dimension. For example, for 2D matrix with 2 rows and 3 columns:
example2D = [3 2 1; 4 5 6];
[minValue,minIndex] = min(example2D,[],'all','linear');
Here minIndex = 5 means row 1 and column 3 (2x2+1).
For your case also, Expression(Index) is equal to Minimum.

类别

在 Help Center 和 File Exchange 中查找有关 Matrix Indexing 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