【matlab中的subs函数】subs函数运行相关问题

Question

以下是提示的问题：

以下是包含与问题相关的代码行：

Answer 1

看了一下那本书提供的源代码，其中:
minRosen.m在第50,80,105行左右第三个参数应用其转置，代码应改为：

function [x,minf] = minRosen(f,A,b,x0,var,eps)
format long;
if nargin == 5
    eps = 1.0e-6;
end

syms l;
x0 = transpose(x0);
n = length(var);
sz = size(A);
m = sz(1);

gf = jacobian(f,var);
bConti = 1;

while bConti
    k = 0;
    s = 0;
    A1 = A;
    A2 = A;
    b1 = b;
    b2 = b;
    for i=1:m
        dfun = A(i,:)*x0 - b(i);
        if abs(dfun)<0.000000001
            k = k + 1;
            A1(k,:) = A(i,:);
            b1(k,1) = b(i);
        else
            s = s+1;
            A2(s,:) = A(i,:);
            b2(s,1) = b(i);
        end
    end
    if k > 0
        A1 = A1(1:k,:);
        b1 = b1(1:k,:);
    end
    if s > 0
        A2 = A2(1:s,:);
        b2 = b2(1:s,:);
    end
    
    while 1
        P = eye(n,n);
        if k > 0
            tM = transpose(A1);
            P = P - tM*inv(A1*tM)*A1;
        end
        gv = Funval(gf, var, x0');
        gv = transpose(gv);
        d = -P*gv;
        if d == 0
            if k == 0
                x = x0;
                bConti = 0;
                break;
            else
                w = inv(A1*tM)*A1*gv;
                if w>=0
                    x = x0;
                    bConti = 0;
                    break;
                else
                    [u,index] = min(w);
                    sA1 = size(A1);
                    if sA1(1) == 1
                        k = 0;
                    else
                        k = sA1(2);
                        A1 =[ A1(1:(index-1),:); A1((index+1):sA1(2),:)];
                    end
                end
            end
        else
            break;
        end
    end

    yl = x0 + l*d;
    tmpf = Funval(f,var,yl');
    bb = b2 - A2*x0;
    dd = A2*d;
    if dd >= 0
        [tmpI,lm] = minJT(tmpf,0,0.1);
    else
        lm = inf;
        for i=1:length(dd)
            if dd(i) < 0
                if bb(i)/dd(i) < lm
                    lm = bb(i)/dd(i);
                end
            end
        end
    end
    [xm,minf] = minHJ(tmpf,0,lm,1.0e-14);
    tol = norm(xm*d);
    if tol < eps 
        x = x0;
        break;
    end
    x0 = x0 + xm*d;  
end

minf = Funval(f,var,x');
x=double(x);
minf=double(minf);
end

为了保证运行速度将minHJ函数x变量取double值：

function [x,minf] = minHJ(f,a,b,eps)
format long;
if nargin == 3
    eps = 1.0e-6;
end

l = a + 0.382*(b-a);
u = a + 0.618*(b-a);
k=1;
tol = b-a;

while tol>eps && k<100000
    fl = subs(f ,symvar(f), l);
    fu = subs(f ,symvar(f), u);
    if fl > fu
        a = l;
        l = u;
        u = a + 0.618*(b - a);
    else
        b = u;
        u = l;
        l = a + 0.382*(b-a);
    end
    k = k+1;
    tol = abs(b - a);
end
if k == 100000
    disp('找不到最小值！');
    x = NaN;
    minf = NaN;
    return;
end
x = (a+b)/2;
x=double(x);
minf = subs(f, symvar(f),x);
format short;

并将大部分代码中已被移除的函数findsym更改为symvar即可