Table/zscore: update doc, add test

matStats/@Table/zscore.m

@@ -1,22 +1,25 @@
 function [res, mu, sigma] = zscore(obj, varargin)
-% Standardized z-score of table data.
+% Standardized z-scores of table data.
 %
-%   Z = zscore(TAB)
-%   Returns a centered a,d scaled version of T, the same size as T.
-%   For vector input T, Z is the vector of z-scores (T-mean(T)) ./ std(T).
-%   For matrix T, z-scores are computed using the mean and standard
-%   deviation along each column of T.
+%   ZTAB = zscore(TAB)
+%   Returns a centered and scaled version of the variables in Table TAB.
+%   The result ZTAB has the same size as input table TAB. For each column,
+%   the resulting column is obtained bu substracting the mean, and dividing
+%   by the standard deviation. Then, for each column of the result the mean
+%   equals 0.0 and the standard deviation equals 1.0 (up to numerical
+%   errors).
 %
-%   [Z, MU, SIGMA] = zscore(T)
+%
+%   [Z, MU, SIGMA] = zscore(TAB)
 %   Also returns mean(T) in MU and std(T) in SIGMA.
 %
-%   [...] = zscore(T, 1) 
-%   normalizes T using std(T,1), i.e., by computing the standard deviation
-%   using N rather than N-1, where N is the number of rows in T.  
-%   zscore(T,0) is the same as zscore(T).
+%   [...] = zscore(TAB, 1) 
+%   Normalizes TAB using std(TAB,1), i.e., by computing the standard
+%   deviation using N rather than N-1, where N is the number of rows in
+%   TAB. zscore(T,0) is the same as zscore(T).
 %
 %   Example
-%     % Compute zscore of Iris numerical variables
+%     % Compute zscore of Iris numerical features
 %     iris = Table.read('fisherIris.txt');
 %     z = zscore(iris(:, 1:4));
 %     [mean(z) ; std(z)]
@@ -31,7 +34,7 @@
 
 % ------
 % Author: David Legland
-% e-mail: david.legland@inra.fr
+% e-mail: david.legland@inrae.fr
 % Created: 2012-07-12,    using Matlab 7.9.0.529 (R2009b)
 % Copyright 2012 INRA - Cepia Software Platform.
 

tests/test_zscore.m

@@ -0,0 +1,29 @@
+function tests = test_zscore
+% Test suite for the file zscore.
+%
+%   Test suite for the file zscore
+%
+%   Example
+%   test_zscore
+%
+%   See also
+%     zscore
+
+% ------
+% Author: David Legland
+% e-mail: [email protected]
+% Created: 2021-04-21,    using Matlab 9.8.0.1323502 (R2020a)
+% Copyright 2021 INRAE - BIA-BIBS.
+
+tests = functiontests(localfunctions);
+
+function test_Simple(testCase) %#ok<*DEFNU>
+% Test call of function without argument.
+
+iris = Table.read('fisherIris.txt');
+irisData = iris(:,1:4);
+
+res = zscore(irisData);
+
+assertEqual(testCase, [0 0 0 0], mean(res.Data), 'AbsTol', 0.01);
+assertEqual(testCase, [1.0 1.0 1.0 1.0], std(res.Data), 'AbsTol', 0.01);