function sTrain = som_train_struct(varargin)
%SOM_TRAIN_STRUCT Default values for SOM training parameters.
%
% sT = som_train_struct([[argID,] value, ...])
%
% sTrain = som_train_struct('train',sM,sD);
% sTrain = som_train_struct('finetune','data',D);
% sTrain = som_train_struct('previous',sT0);
%
% Input and output arguments ([]'s are optional):
% [argID, (string) Several default values depend on other SOM parameters
% value] (varies) or on the proporties of a data set. See below for a
% a list of required and optional arguments for
% different parameters, and well as the list of valid
% argIDs and associated values. The values which are
% unambiguous can be given without the preceeding argID.
%
% sT (struct) The training struct.
%
% Training struct contains values for training and initialization
% parameters. These parameters depend on the number of training samples,
% phase of training, the training algorithm.
%
% Here are the valid argument IDs and corresponding values. The values which
% are unambiguous (marked with '*') can be given without the preceeding rgID.
% 'dim' (scalar) input space dimension
% 'dlen' (scalar) length of the training data
% 'data' (matrix / struct) the training data
% 'munits' (scalar) number of map units
% 'msize' (vector) map size
% 'previous' (struct) previous training struct can be given in
% conjunction with 'finetune' phase (see below)
% 'phase' *(string) training phase: 'init', 'train', 'rough' or 'finetune'
% 'algorithm' *(string) algorithm to use: 'lininit', 'randinit', 'batch' or 'seq'
% 'map' *(struct) If a map struct is given, the last training struct
% in '.trainhist' field is used as the previous training
% struct. The map size and input space dimension are
% extracted from the map struct.
% 'sTrain' *(struct) a train struct, the empty fields of which are
% filled with sensible values
%
% For more help, try 'type som_train_struct' or check out online documentation.
% See also SOM_SET, SOM_TOPOL_STRUCT, SOM_MAKE.
%%%%%%%%%%%%% DETAILED DESCRIPTION %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
% som_train_struct
%
% PURPOSE
%