if i execute its saying type input argument and run the code ? what input argument must type inside that ? please help me

Question

venmal devi 2016-1-26

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/265232-if-i-execute-its-saying-type-input-argument-and-run-the-code-what-input-argument-must-type-inside

回答： Walter Roberson 2016-1-26

% Entropy: Returns entropy (in bits) of each column of 'X'
% by Will Dwinnell
%
% H = Entropy(X)
%
% H = row vector of calculated entropies (in bits)
% X = data to be analyzed
%
% Example: Measure sample entropy of observations of variables with
%   1, 2, 3 and 4 bits of entropy.
%
% Note: Estimated entropy values are slightly less than true, due to
% finite sample size.
%
% X = ceil(repmat([2 4 8 16],[1e3,1]) .* rand(1e3,4));
% Entropy(X)
%
% Last modified: Nov-12-2006
function H = Entropy(X)
% Establish size of data
[n m] = size(X);
% Housekeeping
H = zeros(1,m);
for Column = 1:m,
    % Assemble observed alphabet
    Alphabet = unique(X(:,Column));
  
    % Housekeeping
    Frequency = zeros(size(Alphabet));
  
    % Calculate sample frequencies
    for symbol = 1:length(Alphabet)
        Frequency(symbol) = sum(X(:,Column) == Alphabet(symbol));
    end
  
    % Calculate sample class probabilities
    P = Frequency / sum(Frequency);
  
    % Calculate entropy in bits
    % Note: floating point underflow is never an issue since we are
    %   dealing only with the observed alphabet
    H(Column) = -sum(P .* log2(P));
end
% God bless Claude Shannon.
% EOF

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Answer 1

Walter Roberson 2016-1-26

0
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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/265232-if-i-execute-its-saying-type-input-argument-and-run-the-code-what-input-argument-must-type-inside#answer_207459

That routine should work if you pass it a column vector or 2D matrix, with any of the data types:

double
single
int8
uint8
int16
uint16
int32
uint32
int64
uint64
logical
char

However, it would fail if you were to pass it a cell array or struct of any kind. (There is an easy modification that would permit it to work with cell arrays of string.)