问个函数返回值的问题
function = rsgenpoly(N, K, varargin)%RSGENPOLYGenerator polynomial of Reed-Solomon code.
% GENPOLY = RSGENPOLY(N,K) returns the narrow-sense generator polynomial of a
% Reed-Solomon code with codeword length N and message length K.The codeword
% length N must have the form 2^m-1 for some integer m between 3 and 16.The
% output GENPOLY is a Galois row vector that represents the coefficients of
% the generator polynomial in order of descending powers.The narrow-sense
% generator polynomial is (X-alpha)*(X-alpha^2)*...*(X-alpha^(N-K)), where
% alpha is a root of the default primitive polynomial for the field GF(N+1).
%
% GENPOLY = RSGENPOLY(N,K,PRIM_POLY) is the same as the syntax above, except
% that PRIM_POLY specifies the primitive polynomial for GF(N+1) that has alpha
% as a root.PRIM_POLY is an integer whose binary representation indicates
% the coefficients of the primitive polynomial in order of descending powers.
% To use the default primitive polynomial, set PRIM_POLY to [].
%
% GENPOLY = RSGENPOLY(N,K,PRIM_POLY,B) returns the generator polynomial
% (X-alpha^B)*(X-alpha^(B+1))*...*(X-alpha^(B+N-K-1)), where B is an integer
% and alpha is a root of PRIM_POLY.
%
% = RSGENPOLY(...) returns T, the error-correction capability of
% the code.
%
% Examples:
% g= rsgenpoly(7,3) % Narrow-sense generator polynomial
% g2 = rsgenpoly(7,3,13) % Narrow-sense generator polynomial,
% % with respect to primitive polynomial
% % D^3+D^2+1
% g3 = rsgenpoly(7,3,[],4)% Use b=4
%
% See also GF, RSENC, RSDEC.
% Copyright 1996-2007 The MathWorks, Inc.
% $Revision: 1.4.4.2 $$Date: 2007/09/14 15:57:43 $
% Initial checks
error(nargchk(2,4,nargin,'struct'));
% Number of optional input arguments
nvarargin = nargin - 2;
% Error-correcting capability
t = floor((N-K)/2);
t2 = N-K;
m = log2(N+1);
def_primpoly = 1;
b = 1;% Default : narrow-sense
if any([~isscalar(N) | ~isscalar(K) | floor(N)~=N | floor(K)~=K])
error('comm:rsgenpoly:InvalidNK','N and K must be positive scalar integers.');
end
if t2<1
error('comm:rsgenpoly:NLessThanK','N must be larger than K.');
end
if m~=floor(m) | m<3 | m>16
error('comm:rsgenpoly:InvalidN','N must equal 2^m-1 for some integer m between 3 and 16.')
end
if ~isempty(varargin)
prim_poly = varargin{1};
% Check prim_poly
if isempty(prim_poly)
if ~isnumeric(prim_poly)
error('comm:rsgenpoly:InvalidDefaultPrim_Poly','To use the default PRIM_POLY, it must be marked by [].');
end
else
if ~isscalar(prim_poly)
error('comm:rsgenpoly:Prim_PolyNotScalar','PRIM_POLY must be a scalar integer.');
end
% ZZZ add isprimitive once it's available
def_primpoly = 0;
end
if nvarargin==2
b = varargin{2};
if ~isscalar(b) | floor(b)~=b
error('comm:rsgenpoly:BNotAnInt','B must be an integer scalar.');
end
end
end
% Alpha is the primitive element of this GF(2^m) field
if def_primpoly == 1
alpha = gf(2,m);
else
alpha = gf(2,m,prim_poly);
end
genpoly = 1;
for k=mod(b+,N)
evalc('genpoly = conv(genpoly,);');
end
大家帮忙看看
我想获得这个返回值，即将他赋给一个变量POLY
rsgenpoly(31,25)
POLY = ;
试了改了一下没有成功
多谢啊
>> rsgenpoly(31,25)
ans = GF(2^5) array. Primitive polynomial = D^5+D^2+1 (37 decimal)
Array elements =
1 17 26 30 27 30 24
默认返回这个 >> POLY=rsgenpoly(31,25);
>> POLY
POLY = GF(2^5) array. Primitive polynomial = D^5+D^2+1 (37 decimal)
Array elements =
1 17 26 30 27 30 24
>> POLY(1)
ans = GF(2^5) array. Primitive polynomial = D^5+D^2+1 (37 decimal)
Array elements =
1
>> POLY(1)+POLY(2)
ans = GF(2^5) array. Primitive polynomial = D^5+D^2+1 (37 decimal)
Array elements =
16怎么把POLY变成普通的向量呢？ 专业不懂, 稍微搜下help, 没试成
建议考量简化下 回复 4 # Happy99 的帖子
不是太懂，所以说的也不是太明白哈，我在研究一下
就是把poly变量变成普通的变量，你看那个加法就知道了 只需要在函数的末尾加上genpoly=genpoly.x;因为gf是个结构体，可以用open gf查看代码
运行的结果：>> pp=rsgenpoly(31,25)
pp =
1 17 26 30 27 30 24 回复 6 # qibbxxt 的帖子
多谢哈，成功了 建议不要修改源程序,直接使用POLY=rsgenpoly(31,25); pp=POLY.x即可
昨晚第一时间亦是朝这个方向! 但没试对fieldname, 又一时没找到查询函数(应用fieldnames, 原少个s字)
原来那些值是'x'!
请教gf class的cmd win显示好像与结构体不同, 结构体直接就有fieldname显示!?
回复 8 # Happy99 的帖子
恩，我也是在我的程序里直接提取的，没有改gf域的那个函数，多谢哈～～
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