symerr.m

数字通信第四版原书的例程

function [num, rat] = symerr(x, y, tot)
%SYMERR Symbol error analysis.
%       [NUMBER, RATIO] = SYMERR(X, Y) compares the elements in the two
%       matrices X and Y. The number of the differences is outputted in
%       NUMBER. The ratio of NUMBER to the dimension of Y is output in
%       RATIO. When there is a matrix and there is a vector between X and
%       Y, this function first converts the vector to a matrix with the
%       column number same as the matrix one with each column has the same
%       element, then proceeds with the computation.
%
%       [NUMBER, RATIO] = SYMERR(X, Y, 'columnwise') specifies that the output
%       NUMBER and RATIO are row vectors, which are the number and ratio for
%       each columnwise comparison.
%
%       See also BITERR.

%       Wes Wang 1/14/94, 10/11/95.
%       Copyright (c) 1995-96 by The MathWorks, Inc.
%       $Revision: 1.1 $  $Date: 1996/04/01 18:03:59 $

[nx, mx] = size(x);
[ny, my] = size(y);

if (min(nx, mx) < 1) | (min(ny, my) < 1)
    num = [];
    rat = [];
    return;
elseif (min(nx, mx) > 1) & (min(ny, my) > 1)
    if (nx ~= ny) | (mx ~= my)
        error('Dimentions must be agree.')
    end;
else
    if min(nx, mx) <= 1
        x = x(:);
        if (size(x, 1) ~= ny)
            error('Dimentions must be agree.')
        else
            x = x * ones(1, my);
        end;
    elseif min(ny, my) <= 1
        y = y(:);
        if (size(y, 1) ~= nx)
            error('Dimentions must be agree.')
        else
            y = y * ones(1, mx);
        end;
        [ny, my] = size(y);
    else
        error('Dimentions must be agree.')
    end;
end;

z = abs(x - y);

if nargin <= 2
    num = length(find(z ~= 0));
    rat = num / (ny * my);
else
    [indx, indy] = find(z ~= 0);
    num = zeros(1, my);
    for i = 1 : my
        num(i) = sum(indy == i);
    end;
    num = num / ny;
end;

%--- end of symerr---