# Normalize/scale in range

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Pete on 16 Oct 2019
Answered: Kaashyap Pappu on 21 Oct 2019
hi all,
I would like to normalize values in a 18x17 matrix to have values between -1 and 1.
I would also like to be able to say that 0 = 76 mm, -1 = 71 mm, 1 = 81 mm for example instead of just using the min and max values in the array.
Any help would be greatly appreciated!
dpb on 16 Oct 2019
You can't do both unless the min/max are <= the chosen min/max.
NB: if you do choose the above three points the scaling between negative and positive results will be skewed by a significant amount -- double, in fact.
But, it's simply solving for the linear coefficients between the two...or you could use interp1

Kaashyap Pappu on 21 Oct 2019
The code below can help perform matrix normalization where you have to specify the appropriate -1, 0 and 1 values in variables "pointZero", "pointPositive" and "pointNegative". Any value lower than -1 is set to -1 and any value greater than one is set to 1.
a = (a - pointZero)/(pointPositive-pointNegative);
a(a<-1)=-1;
a(a>1)=1;
Note that the points raised by dpb are valid and could affect the properties of the values in the matrix.
Hope this helps!