4楼: Originally posted by hppdyx at 2013-12-12 20:26:07
首先，你这个程序里面有很多小细节上的错误，还有一些错误需要你解释一下才行。我把你的程序改了一下，调试之后可以了，不过不知道符不符合你的要求。
function k = res2

syms x
w = 0.9 : 0.01 : 1.1; %21个 ...

function k = res2

syms x
w = 0.9 : 0.01 : 1.1;
gamma = 1.1 : 0.2 : 10;  
c = 3 * 10^8;

R = 2.3 * 10^-2;

n1 = length(w);
n2 = length(gamma);
v = zeros(n2);
y = zeros(n1);
wpb = zeros(n2);
f = sym(zeros(n1, n2));
k = zeros(n1 * n2, 1);

for j = 1 : n2       
    v(j) = c * sqrt(1 - 1 ./ gamma(j).^2);
    for i = 1 : n1       
    y(i) = 1 + 0.2^2 ./ (1 - w(i).^2 + 2 * i * 0.015 * w(i));
    wpb(j) = sqrt((1.602 * 10^-19)^2 * 10^9 ./ (9.109 * 10^-31 * 8.85 * 10^-12 * gamma(j)^3));
    f(i, j) = (y(i) * (w(i) * 2 * pi * 24 * 10^9)^2 / c^2 - x^2) * (1 - (wpb(j) * 2 * pi * 24 * 10^9)^2 / (((w(i) * 2 * pi * 24 * 10^9) - x * v(j))^2 * y(i))) - 2.4048^2 / R^2;
    k((i-1) * n2 + j) = max(abs(eval(solve(f(i, j)))));  
    end
end
semilogy(gamma, k(1:n2), 'b--');
figure;
plot(gamma, k(1:n2), 'r');

2楼: Originally posted by hppdyx at 2013-12-06 13:09:21
我没有试，也不知道出的什么错误，不过solve求解都是把变量当作sys来看，所以求解出来的解是表达式而不是数值，因此可以试着加上eval函数，看看行不行

3楼: Originally posted by watertxf at 2013-12-10 14:32:57
非常感谢您的帮助！我对matlab不是太熟悉，能不能麻烦您告诉我怎样加上eval函数求解？不胜感激！...

function k = res2

syms x
w = 0.9 : 0.01 : 1.1; %21个
gamma = 1.1 : 0.5 : 10;   %18个
c = 3 * 10^8;

R = 2.3 * 10^-2;

n1 = length(w);
n2 = length(gamma);
v = zeros(n2);
y = zeros(n1);
wpb = zeros(n2);
f = sym(zeros(n1, n2));
k = zeros(n1 * n2, 1);

for j = 1 : 18        %gamma
    v(j) = c * sqrt(1 - 1 ./ gamma(j).^2);
    for i = 1 : 21        %w
    y(i) = 1 + 0.2^2 ./ (1 - w(i).^2 + 2 * i * 0.015 * w(i));
    wpb(j) = sqrt((1.602 * 10^-19)^2 * 10^9 ./ (9.109 * 10^-31 * 8.85 * 10^-12 * gamma(j)^3));
    f(i, j) = (y(i) * (w(i) * 2 * pi * 24 * 10^9)^2 / c^2 - x^2) * (1 - (wpb(j) * 2 * pi * 24 * 10^9)^2 / (((w(i) * 2 * pi * 24 * 10^9) - x * v(j))^2 * y(i))) - 2.4048^2 / R^2;
    k((i-1) * n2 + j) = max(sqrt(eval(solve(f(i, j)))));  
    end
end
semilogy(gamma, k(1:18), 'b--');
figure;
plot(gamma, k(1:18), 'r');