normalization - VB.NET Normalizing Data [1, -1] -

i using following code normalize data:

public function normalizedata(values double()) double()     dim min = values.min     dim max = values.max     dim outlist(values.count - 1) double     = 0 values.count - 1         outlist(i) = (values(i) - min) / (max - min)     next     return outlist end function 

this returns values 0 1 accordingly. confused on how make normalize between [1, -1] instead of [1, 0].

you know how normalise range of 0 1. if want range -1 1, need multiply normalised data 2 , subtract 1.

as said in comment, modify statement inside loop adjust data:

outlist(i) = 2 * (values(i) - min) / (max - min) - 1 

the equivalent statement denormalise data be:

outlist(i)= (values(i) + 1) * (max - min) / 2 + min 

if need normalise , denormalise several arrays of data, suggest creating normaldata class can store normalised data maximum , minimum values , has properties return either normalised or denormalised values. here example of such class. can create using either

• an array of unnormalised data, or ...
• an array of normalised data , minimum , maximum values

the normalvalues , values properties return normalised , denormalised data respectively.

public class normaldata     ''' <summary>create normaldata object , unnormalised array of values</summary>     ''' <param name="values">unnormalised values</param>     sub new(values() double)         minimum = values.min         maximum = values.max         normalvalues = values.select(function(val) 2 * (val - minimum) / (maximum - minimum) - 1).toarray     end sub      ''' <summary>create normaldata object , normalised array of values</summary>     ''' <param name="normal">normalised values</param>     ''' <param name="min">minimum value of unnormalised data</param>     ''' <param name="max">maximum value of unnormalised data</param>     sub new(normal() double, min double, max double)         minimum = min         maximum = max         normalvalues = normal     end sub      readonly property minimum double     readonly property maximum double      readonly property normalvalues double()      readonly property values double()                     return normalvalues.select(function(norm) (norm + 1) * (maximum - minimum) / 2 + minimum).toarray         end     end property end class