Poissonscale

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Revision as of 15:46, 26 July 2011 by imported>Jeremy (Created page with "===Purpose=== Perform Poisson scaling with scaling offset. ===Synopsis=== :[xs,sc] = poissonscale(x,''options''); %calibrate scaling :xs = poissonscale(x,sc); ...")
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Purpose

Perform Poisson scaling with scaling offset.

Synopsis

[xs,sc] = poissonscale(x,options); %calibrate scaling
xs = poissonscale(x,sc); %apply previous scaling

Description

Scales each variable by its square root mean value. When no scale values are passed, a calibration is performed in which the square root mean values are calculated for each variable and then these are applied to the input data. If previously calculated scales are passed, these are simply applied to the data. An optional options structure allows setting of the offset which is added to each mean to avoid over-scaling when a variable has a near-zero mean.


Inputs

  • x = Data to be scaled (double or DataSet object).

Optional Inputs

  • sc = Vector of previously-calculated scales. Must be equal in length to the number of included x-block variables.
  • options = Options structure. See Options section below.

Outputs

  • xs = Scaled data.
  • sc = Vector of scales calculated for given data.

Options

options = a structure array with the following fields:

  • offset: [ 3] percent of the maximum mean value to be used as an offset on all scales. Avoids division by near-zero means.

See Also

auto, preprocess, rescale, scale