How to normalize values in a matrix to be between 0 and 1?

Question

Sahar abdalah 2015-4-8

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https://ww2.mathworks.cn/matlabcentral/answers/196798-how-to-normalize-values-in-a-matrix-to-be-between-0-and-1

评论： Tubi 2018-3-22

I have a matrix Ypred that contain negative values and I want to normalize this matrix between 0 and 1

 Ypred=[-0.9630 -1.0107 -1.0774
       -1.2075 -1.4164 -1.2135
       -1.0237 -1.0082 -1.0714
       -1.0191 -1.3686 -1.2105];

I'm new in matlab, please help me, there is a matlab function or toolbox that can do this? thanks

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James Tursa 2015-4-8

编辑：James Tursa 2015-4-8

What do you mean by "normalize"? Divide by the max value in the matrix and make all values positive? Do this by columns or rows? Divide by norm of columns or rows? Or what?

Sahar abdalah 2015-4-8

I want to divide by norm of row to make positive values

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Answer 1

Jos (10584) 2015-4-8

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https://ww2.mathworks.cn/matlabcentral/answers/196798-how-to-normalize-values-in-a-matrix-to-be-between-0-and-1#answer_174487

编辑：Jos (10584) 2015-4-8

在 MATLAB Online 中打开

This can be simply done in a two step process

subtract the minimum
divide by the new maximum

normA = A - min(A(:))
normA = normA ./ max(normA(:)) % *

note that A(:) makes A into a long list of values. Otherwise min(A) would not return a single value ... Try fro yourself!

Edited after comment ...

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Sahar abdalah 2015-4-8

在 MATLAB Online 中打开

Thanks for the code, I just tried this and it not normalised between 0 and 1

Ypred =

   -0.9630   -1.0107   -1.0774
   -1.2075   -1.4164   -1.2135
   -1.0237   -1.0082   -1.0714
   -1.0191   -1.3686   -1.2105

normA =

4534    0.4057    0.3390
2089         0    0.2029
3927    0.4082    0.3450
3973    0.0478    0.2059

normA =

0000    1.0495    1.1188
2539    1.4708    1.2601
0630    1.0469    1.1126
0583    1.4212    1.2570

Jos (10584) 2015-4-8

在 MATLAB Online 中打开

Sorry! The second line of code is wrong ;-) It should read

normA = normA ./ max(normA(:))

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Answer 2

James Tursa 2015-4-8

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在 MATLAB Online 中打开

NormRows = sqrt(sum(Ypred.*Ypred,2));
Ynorm = bsxfun(@rdivide,abs(Ypred),NormRows);

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John D'Errico 2018-3-10

编辑：John D'Errico 2018-3-10

Why would you need a citation? If you truly want a citation, just cite MATLAB itself, or perhaps the doc page for bsxfun, but it seems a bit silly to need a citation for a simple code fragment.

Tubi 2018-3-22

Many Thanks John, I believe you are right in your suggestion since they are mostly common MATLAB commands and functions.

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Answer 3

Sahar abdalah 2015-4-9

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https://ww2.mathworks.cn/matlabcentral/answers/196798-how-to-normalize-values-in-a-matrix-to-be-between-0-and-1#answer_174510

在 MATLAB Online 中打开

thank you for your answers. I used both codes and I found two different result. what is the result that I can use?

    normA = Ypred - min(Ypred(:))
    normA = normA ./ max(normA(:))
    normA =
    1.0000    0.8948    0.7477
    0.4607         0    0.4475
    0.8661    0.9003    0.7609
    0.8763    0.1054    0.4541
   NormRows = sqrt(sum(Ypred.*Ypred,2));
   Ynorm = bsxfun(@rdivide,abs(Ypred),NormRows);
   Ynorm =
    0.5461    0.5731    0.6110
    0.5435    0.6375    0.5462
    0.5712    0.5625    0.5978
    0.4871    0.6542    0.5786

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James Tursa 2015-4-9

Use whichever is appropriate for your problem. Jos and I are both trying to interpret what you want, but without any background about the problem you are solving it is a bit of a guessing game at our end.

Sahar abdalah 2015-4-9

ok thanks

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Answer 4

c4ndc 2017-8-12

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https://ww2.mathworks.cn/matlabcentral/answers/196798-how-to-normalize-values-in-a-matrix-to-be-between-0-and-1#answer_277770

Hello, What is the name of this norm in the accepted answer? (Euclidean, Frobenius etc.)

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Jan 2017-8-12

Please post comments to answers in the section for the comments. You message is not an answer.

The accepted answer does not contain a norm at all, but a "normalization". A matrix norm would reply a scalar, the normalization replies a matrix with the same size, but with shifted and scaled values.

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