rands函数的用法

ゝ一世哀愁。 2022-05-16 10:25 266阅读 0赞

有如下程序，

clc; clear; \[a,b\]=rands(5,1); a b \[c,d\]=rands(1,5); c d

输出如下：

a =  
  
\-0.5749  
0.6785  
0.2576  
\-0.7325  
\-0.5857  
  
  
b =  
  
0.2144  
0.2598  
\-0.2590  
0.1503  
\-0.0972  
  
  
c =  
  
\-0.9122 -0.9456 -0.3746 -0.9743 -0.2321  
  
  
d =  
  
0.3662

有关rands函数说明如下：

rands  
  
Symmetric random weight/bias initialization function  
Syntax  
W = rands(S,PR)  
M = rands(S,R)  
v = rands(S);  
  
Description  
  
rands is a weight/bias initialization function.  
rands(S,PR) takes,  
S -- Number of neurons  
PR -- R x 2 matrix of R input ranges  
and returns an S-by-R weight matrix of random values between -1 and 1.  
rands(S,R) returns an S-by-R matrix of random values. rands(S) returns an S-by-1 vector of random values.  
Examples  
  
Here three sets of random values are generated with rands. rands(4,\[0 1; -2 2\])  
rands(4)  
rands(2,3)  
  
Network Use  
  
To prepare the weights and the bias of layer i of a custom network to be initialized with rands Set net.initFcn to 'initlay'. (net.initParam will automatically become initlay's default parameters.) Set net.layers\{i\}.initFcn to 'initwb'. Set each net.inputWeights\{i,j\}.initFcn to 'rands'. Set each net.layerWeights\{i,j\}.initFcn to 'rands'. Set each net.biases\{i\}.initFcn to 'rands'.  
To initialize the network call init

--------------------

没有说明，如何出现上述结果，百度之：

function [w,b] = rands(s,pr)
    
    
    %RANDS Symmetric random weight/bias initialization function.
    
    
    %
    
    
    %  Syntax
    
    
    %
    
    
    %    W = rands(S,PR)
    
    
    %    M = rands(S,R)
    
    
    %    v = rands(S);
    
    
    %
    
    
    %  Description
    
    
    %
    
    
    %    RANDS is a weight/bias initialization function.
    
    
    %
    
    
    %    RANDS(S,PR) takes,
    
    
    %      S  - number of neurons.
    
    
    %      PR - Rx2 matrix of R input ranges.
    
    
    %    and returns an S-by-R weight matrix of random values between -1 and 1.
    
    
    %
    
    
    %    RANDS(S,R) returns an S-by-R matrix of random values.
    
    
    %    RANDS(S) returns an S-by-1 vector of random values.
    
    
    %
    
    
    %  Examples
    
    
    %
    
    
    %    Here three sets of random values are generated with RANDS.
    
    
    %
    
    
    %      rands(4,[0 1; -2 2])
    
    
    %      rands(4)
    
    
    %      rands(2,3)
    
    
    %
    
    
    %  Network Use
    
    
    %
    
    
    %    To prepare the weights and the bias of layer i of a custom network
    
    
    %    to be initialized with RANDS:
    
    
    %    1) Set NET.initFcn to 'initlay'.
    
    
    %       (NET.initParam will automatically become INITLAY's default parameters.)
    
    
    %    2) Set NET.layers{i}.initFcn to 'initwb'.
    
    
    %    3) Set each NET.inputWeights{i,j}.initFcn to 'rands'.
    
    
    %       Set each NET.layerWeights{i,j}.initFcn to 'rands';
    
    
    %       Set each NET.biases{i}.initFcn to 'rands'.
    
    
    %
    
    
    %    To initialize the network call INIT.
    
    
    %
    
    
    %  See also RANDNR, RANDNC, INITWB, INITLAY, INIT
    
    
    
    
    % Mark Beale, 1-31-92
    
    
    % Revised 12-15-93, MB
    
    
    % Revised 11-31-97, MB
    
    
    % Copyright 1992-2008 The MathWorks, Inc.
    
    
    % $Revision: 1.1.6.7 $  $Date: 2008/06/20 08:04:33 $
    
    
    
    
    fn = mfilename;
    
    
    if (nargin < 1), error('NNET:Arguments','Not enough arguments.'); end
    
    
    if ischar(s)
    
    
      switch(s)
    
    
        case 'name'
    
    
          w = 'Midpoint';
    
    
        otherwise, error('NNET:Arguments',['Unrecognized code: ''' s ''''])
    
    
      end
    
    
      return
    
    
    end
    
    
    
    
    if nargin == 1
    
    
      r = 1;
    
    
    elseif size(pr,2) == 1
    
    
      r = pr;
    
    
    else
    
    
      r = size(pr,1);
    
    
    end
    
    
    w = 2*rand(s,r)-1;//注意
    
    
    
    
    
    
    % **[ NNT2 Support ]**
    
    
    if nargout == 2
    
    
      b = 2*rand(s,1)-1; //注意