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How to convert a matrix of double to int?

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Emilie Mussard
Emilie Mussard 2013년 12월 5일
댓글: Nguyen Phuong 2019년 9월 11일
I need to convert my matrix [648x2400 double] into integers value to use a mRMR function, but I do not know how to do that. I have tried to convert by uint8(matrix) or int8(matrix) but it does not give integers... And I always have this note: "Undefined function 'mrmr_mid_d' for input arguments of type 'int8' " (or double, or uint, and so on) can someone help me? thank you
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Nguyen Phuong
Nguyen Phuong 2019년 9월 11일
img_d = double(img);

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채택된 답변

Wayne King
Wayne King 2013년 12월 5일
편집: Wayne King 2013년 12월 5일
I'm not sure what you are saying. Do you mean that:
X = 10+randn(16,16);
X = uint8(X);
Does not result in integers for the output in X?
The error message you report ("Undefined function 'mrmr_mid_d' for input arguments of type 'int8' ") just sounds like MATLAB cannot recognize the function, mrmr_mid_d.m.
You need to add the folder containing that function to the MATLAB path. You can launch
to add that folder.
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Emilie Mussard
Emilie Mussard 2013년 12월 5일
Thank you, I hadn't thought of the path problem and I focused on a wrong problem!

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추가 답변(3개)

Kelly Kearney
Kelly Kearney 2013년 12월 5일
It's possible that mrmr_mid_d.m isn't on your path; the other possibility is that it doesn't actually accept integer data types as input, but integer values stored as double arrays. In this case, you need to round your data in some manner (see round, ceil, floor, fix, etc)
x = rand(10)*10;
x = round(x);
mrmr_mid_d(x); % or whatever the syntax is...

MathWorks Support Team
MathWorks Support Team 2018년 11월 27일
To convert an array of type “double” to an integer type, you can use a function such as “int64”, which converts the input to a 64-bit integer. For example, consider the following:
x_double = [1 2 3];
x_int = int64(x)
For more information on integer types and functions, see

sixwwwwww 2013년 12월 5일
you can do it as follow:
a = randi(100, 4);
a = int64(a);
see following link for more information about integer data types:
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Munawara Munia
Munawara Munia 2016년 4월 26일
Hi Emilie, I am facing the same problem. I ama also trying to use mRMR and getting the same errors. Could you kindly tell me what was the issues with your code and how you solved it..?? Badly need a solution about it. Thanks in advance. :)

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