How to Normalize a matrix between 0-1 containing NaNs?

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ML
ML 2016-9-5
回答： Stephen23 2016-9-5
Can anyone help me please to normalize a matrix between 0-1 which contains NaNs?
the following makes whole the matrix zero
d = A - min (A(:));
nrmdata = d./max(d(:));
  2 个评论
Walter Roberson
Walter Roberson 2016-9-5
I do not seem to be able to reproduce the problem. Could you attach a .mat with your A values?

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回答（3 个）

KSSV
KSSV 2016-9-5
编辑：KSSV 2016-9-5
clc; clear all ;
load A.mat ;
idx = isinf(A) ; % get the positions of inf in A
B = A ; % B as A
B(idx) = 0 ; % repalce inf's in B with 0
% normalize the B matrix
norm_A = (B - min(B(:))) / ( max(B(:)) - min(B(:)) ) ;
norm_A(idx) = inf ; % replace norm_A with inf in previous locations/ if required
or
clc; clear all ;
load A.mat ;
m0 = min(A(isfinite(A(:)))); % get minimum in A
m1 = max(A(isfinite(A(:)))); % get maximum in A
norm_A = (A -m0)/(m1-m0 ) ;
Walter Roberson
Walter Roberson 2016-9-5
You cannot normalize data that contains infinity, not unless you are willing to ignore the infinity.
By definition, any finite real value is a negligible fraction of infinity, so when you normalize against infinity, all finite values become 0.
Stephen23
Stephen23 2016-9-5
Ignoring infinity:
S = load('A.mat');
A = S.A;
idx = isfinite(A);
Amax = max(A(idx));
Amin = min(A(idx));
B = (A-Amin) / (Amax-Amin);
and checking:
>> min(B(isfinite(B)))
ans = 0
>> max(B(isfinite(B)))
ans = 1

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