CODEWITHSUNDEEP
matlab
Mike
Mike

Reputation: 331

Passing parameters to a Matlab function

I have a very simple question, but I didn't figure out how to solve this.I have the function definition below:

function model = oasis(data, class_labels, parms)
% model = oasis(data, class_labels, parms)
%
% Code version 1.3 May 2011 Fixed random seed setting
% Code version 1.2 May 2011 added call to oasis_m.m
% Code version 1.1 May 2011 handle gaps in class_labels
% 
%  Input:
%   -- data         - Nxd sparse matrix (each instance being a ROW)
%   -- class_labels - label of each data point  (Nx1 integer vector)
%   -- parms (do sym, do_psd, aggress etc.)
% 
%  Output: 
%   -- model.W - dxd matrix
%   -- model.loss_steps - a binary vector: was there an update at
%         each iterations
%   -- modeo.parms, the actual parameters used in the run (inc. defaults)
% 
%  Parameters:
%   -- aggress: The cutoff point on the size of the correction
%         (default 0.1) 
%   -- rseed: The random seed for data point selection 
%         (default 1)
%   -- do_sym: Whether to symmetrize the matrix every k steps
%         (default 0)
%   -- do_psd: Whether to PSD the matrix every k steps, including
%         symmetrizing them (defalut 0)
%   -- do_save: Whether to save the intermediate matrices. Note that
%         saving is before symmetrizing and/or PSD in case they exist
%         (default 0)
%   -- save_path: In case do_save==1 a filename is needed, the
%         format is save_path/part_k.mat
%   -- num_steps - Number of total steps the algorithm will
%         run (default 1M steps)
%   -- save_every: Number of steps between each save point
%         (default num_steps/10)
%   -- sym_every: An integer multiple of "save_every",
%         indicates the frequency of symmetrizing in case do_sym=1. The
%         end step will also be symmetrized. (default 1)
%   -- psd_every: An integer multiple of "save_every",
%         indicates the frequency of projecting on PSD cone in case
%         do_psd=1. The end step will also be PSD. (default 1)
%   -- use_matlab: Use oasis_m.m instead of oasis_c.c
%      This is provided in the case of compilation problems.
%

I want to use this function, but I don't figure how to set the parameters, or use the default values. What is the variable parms in this case, it is an object that keep all the other variables? Can I make something python like syntax where we put the name of the parameter plus value? For example:

model = oasis(data_example, labels_example, agress = 0.2)

Additionally, If I have understood correctly, I get two Objects in the Output, which is model and modeo, so I need to make this call to receive all contents this function returns? 

[model,modeo] = oasis(data_example, labels_example, ?(parms)?)

Upvotes: 0

Views: 191

Answers (2)

Tamás Szabó
Tamás Szabó

Reputation: 733

From your function definition it seems like params is simply a placeholder for the parameters. Typically the parameters themselves are passed as pairs of inputs in the form:

model = oasis(data, class_labels, 'do_sym',do_symValue, 'do_psd', do_psdValue,...)

where do_symValue and do_psdValue are the values you want to pass as the respective parameters.

As for the functions return value, it returns a single struct with members W, loss_steps, and parms. I believe that what you thought as a second output (modelo) is simply a typo in the text - at least based on the function's definition.

Upvotes: 1

Daniel
Daniel

Reputation: 36720

From the documentation above, I don't know which one is the right, but there are two common ways for optional parameters in matlab.

parameter value pairs:

model = oasis(data, class_labels, 'do_sym',1,'do_psd',0)

structs:

params.do_sym=1
params.do_psd=0
model = oasis(data, class_labels, params)

Probably one of these two possibilities is right.

Upvotes: 0

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