step:最后显示准确率图时的步进大小.默认为 1.5
% 输出:
% bestacc:Cross Validation 过程中的最高分类准确率
% bestc:最佳的参数c
% bestg:最佳的参数g

% about the parameters of SVMcgForClass
if nargin < 10
    accstep = 4.5;
end
if nargin < 8
    cstep = 1;
    gstep = 1;
end
if nargin < 7
    v = 3;
    cstep = 1;
    gstep = 1;
end
if nargin < 6
    v = 3;
    cstep = 1;
    gstep = 1;
    gmax = 5;
end
if nargin < 5
    v = 3;
    cstep = 1;
    gstep = 1;
    gmax = 5;
 