最后编辑 发布了指向另一个question的链接，但问题相同。 有些事情不应该在matlab中完成......也许其他人会问这个，所以我的结论在上面的链接中。
我的编码很难为我阅读而且我经常犯错误，所以我认为一个函数会有所帮助。
编辑2将旧问题移到最后并改进了
如果未知与计算相关，我希望vpasolve至少自动添加方程式或删除它们。
因此，假设我有4个未知数：r1, r2, r3, r4和4个方程式。怎么做到这一点：
syms if r1<=0
r1=0
else
'r1'
same for the other `r`'s;
[if r1<=0
r1=0
else
'r1'
same for the other `r`'s] = vpasolve([if r1<=0
` `
else
'equation1'
same for the other `r`'s], [if r1<=0
r1=0
else
'r1'
same for the other `r's]);
条件可能并不总是和＆gt; = 0 ...
一样容易还欢迎更好的方法，因为使用for j=2:~40需要一些时间来完成所有这些（最后移动）。如果我也理解为什么不使用我的所有CPU内核，那么很大的问题就可以解决了。
谢谢你， 丹。
移动的内容
我希望vpasolve根据给定的n解算n等式。我的n可以是12或16，将来也会有超过这两种可能性。如下所示：
function y=custvpas(a,b,c,d,e,f,g,h,n)
if n=12
...
else
...
end
编辑1：我删除了原始的vpasolve代码，因为这个代码要好得多，而且我已经添加了它现在的工作方式。
om(1)=2.76;
om(2)=27.5/56;
om(3)=23.5/56;
om(4)=1;
om(5)=5/1000;
om(6)=50/1000;
om(7)=1/1000;
vb0max=uint8((om(1)+om(3))*10);
cct(1)=om(1)*om(5)/om(6);
c=zeros(15,vb0max);
ct=zeros(4,vb0max);
v=zeros(4,vb0max);
a=zeros(3,vb0max);
v(1,1)=om(6);
ct(1,1)=2*cct(1);
ct(2,1)=om(2)*om(5)/v(1,1);
ct(3,1)=om(3)*om(5)/v(1,1);
cct(4)=cct(1)+ct(2,1)+3/2*ct(3,1);
t = animatedline;
axis([0,vb0max+3,0,7])
for j=1:1
func12
v(1,j+1)=v(1,j)+om(7);
v(2,j+1)=v(2,j)+om(7);
c(14,j)=10^(-14)/c(1,j);
pH(j)=-log10(c(1,j));addpoints(t,v(2,j)*1000,pH(j));drawnow
pause(0.05)
end
for j=2:vb0max+3
v(1,j)=v(1,j-1)+om(7);v(2,j)=v(2,j-1)+om(7);c(15,j)=v(2,j)*om(4)/v(1,j);
if 6*10^(-38)>(c(3,j-1)*v(1,j-1)-0.0001)/v(1,j)*(10^(-14)/(c(1,j-1)*v(1,j-1)-0.0007)/v(1,j))^3
ct(1,j)=(ct(1,j-1)*v(1,j-1)-om(4)*om(7))/v(1,j);
ct(2,j)=ct(2,j-1)*v(1,j-1)/v(1,j);
ct(3,j)=ct(3,j-1)*v(1,j-1)/v(1,j);
v(3,j)=om(7);v(4,j)=0;
func12
c(14,j)=10^(-14)/c(1,j);
else
ct(2,j)=ct(2,j-1)*v(1,j-1)/v(1,j);
func16
if isequal(size(r1), size([0]))
ct(1,j)=(ct(1,j-1)*v(1,j-1)-om(4)*r111)/v(1,j);
ct(3,j)=(ct(3,j-1)*v(1,j-1)-om(4)*r333)/v(1,j);
v(3,j)=r111;v(4,j)=r333;
else
ct(1,j)=(ct(1,j-1)*v(1,j-1)-om(4)*om(7))/v(1,j);
ct(3,j)=ct(3,j-1)*v(1,j-1)/v(1,j);
v(3,j)=om(7);v(4,j)=0;
func12
end
c(14,j)=10^(-14)/c(1,j);
end
pH(j)=-log10(c(1,j));addpoints(t,v(2,j)*1000,pH(j));drawnow
pause(0.05);
end
这是我的func12
r1t=ct(1,j);r2t=ct(2,j);r3t=ct(3,j);
syms r1 r2 r3 r4 r5 r6 r7 r8 r9 r10 r11 r12;
[r1, r2, r3, r4, r5, r6, r7, r8, r9, r10, r11, r12] = vpasolve([r1t==r1+r5+r6+r8,
r2t==r2+r6+r7,
r3t==r3+r8+r9+r10+r11+r12,
cct(4)==r4+r5+r6+r7+r8+r9+2*r10,
r5==r4*r1*10^1.98,
r6==r4*r1*r2*10^1.08,
r7==r4*r2*10^2.25,
r8==r4*r1*r3*10^2.48,
r9==r4*r3*10^4.04,
r10==r4^2*r3*10^5.38,
r11==1.9*10^(-3)*r3/r1,
r12==2.5*10^(-3)*r3/r1^2], [r1, r2, r3, r4, r5, r6, r7, r8, r9, r10, r11, r12]);
index = find(r12>=0); r10 = r10(index);r1 = r1(index);r2 = r2(index);r3 = r3(index);r4 = r4(index);r5 = r5(index);r6 = r6(index);r7 = r7(index);r8 = r8(index);r9 = r9(index);r11 = r11(index);r12 = r12(index);index = find(r11>=0); r10 = r10(index);r1 = r1(index);r2 = r2(index);r3 = r3(index);r4 = r4(index);r5 = r5(index);r6 = r6(index);r7 = r7(index);r8 = r8(index);r9 = r9(index);r11 = r11(index);r12 = r12(index);index = find(r10>=0); r10 = r10(index);r1 = r1(index);r2 = r2(index);r3 = r3(index);r4 = r4(index);r5 = r5(index);r6 = r6(index);r7 = r7(index);r8 = r8(index);r9 = r9(index);r11 = r11(index);r12 = r12(index);index = find(r9>=0); r10 = r10(index);r1 = r1(index);r2 = r2(index);r3 = r3(index);r4 = r4(index);r5 = r5(index);r6 = r6(index);r7 = r7(index);r8 = r8(index);r9 = r9(index);r11 = r11(index);r12 = r12(index);index = find(r8>=0); r10 = r10(index);r1 = r1(index);r2 = r2(index);r3 = r3(index);r4 = r4(index);r5 = r5(index);r6 = r6(index);r7 = r7(index);r8 = r8(index);r9 = r9(index);r11 = r11(index);r12 = r12(index);index = find(r7>=0); r10 = r10(index);r1 = r1(index);r2 = r2(index);r3 = r3(index);r4 = r4(index);r5 = r5(index);r6 = r6(index);r7 = r7(index);r8 = r8(index);r9 = r9(index);r11 = r11(index);r12 = r12(index);index = find(r6>=0); r10 = r10(index);r1 = r1(index);r2 = r2(index);r3 = r3(index);r4 = r4(index);r5 = r5(index);r6 = r6(index);r7 = r7(index);r8 = r8(index);r9 = r9(index);r11 = r11(index);r12 = r12(index);index = find(r5>=0); r10 = r10(index);r1 = r1(index);r2 = r2(index);r3 = r3(index);r4 = r4(index);r5 = r5(index);r6 = r6(index);r7 = r7(index);r8 = r8(index);r9 = r9(index);r11 = r11(index);r12 = r12(index);index = find(r4>=0); r10 = r10(index);r1 = r1(index);r2 = r2(index);r3 = r3(index);r4 = r4(index);r5 = r5(index);r6 = r6(index);r7 = r7(index);r8 = r8(index);r9 = r9(index);r11 = r11(index);r12 = r12(index);index = find(r3>=0); r10 = r10(index);r1 = r1(index);r2 = r2(index);r3 = r3(index);r4 = r4(index);r5 = r5(index);r6 = r6(index);r7 = r7(index);r8 = r8(index);r9 = r9(index);r11 = r11(index);r12 = r12(index);index = find(r2>=0); r10 = r10(index);r1 = r1(index);r2 = r2(index);r3 = r3(index);r4 = r4(index);r5 = r5(index);r6 = r6(index);r7 = r7(index);r8 = r8(index);r9 = r9(index);r11 = r11(index);r12 = r12(index);index = find(r1>=0); r10 = r10(index);r1 = r1(index);r2 = r2(index);r3 = r3(index);r4 = r4(index);r5 = r5(index);r6 = r6(index);r7 = r7(index);r8 = r8(index);r9 = r9(index);r11 = r11(index);r12 = r12(index);
c(1,j)=r1;c(2,j)=r2;c(3,j)=r3;c(4,j)=r4;c(5,j)=r5;c(6,j)=r6;c(7,j)=r7;c(8,j)=r8;c(9,j)=r9;c(10,j)=r10;c(11,j)=r11;c(12,j)=r12;
这是我的func16
r2t=ct(2,j);
syms r1 r2 r3 r4 r5 r6 r7 r8 r9 r10 r11 r12 r1t r3t r111 r333;[r1,r2,r3,r4,r5,r6,r7,r8,r9,r10,r11,r12,r1t,r3t,r111,r333]=vpasolve([
r1t==r1+r5+r6+r8,
r2t==r2+r6+r7,
r3t==r3+r8+r9+r10+r11+r12,
cct(4)==r4+r5+r6+r7+r8+r9+2*r10,
r5==r4*r1*10^1.98,
r6==r4*r1*r2*10^1.08,
r7==r4*r2*10^2.25,
r8==r4*r1*r3*10^2.48,
r9==r4*r3*10^4.04,
r10==r4^2*r3*10^5.38,
r11==1.9*10^(-3)*r3/r1,
r12==2.5*10^(-3)*r3/r1^2
6*10^(-38)==r3*(10^(-14)/r1)^3,
r1t==(ct(1,j-1)*v(1,j-1)-om(4)*r111)/v(1,j),
r3t==(ct(3,j-1)*v(1,j-1)-om(4)/3*r333)/v(1,j),
om(7)==r111+r333
], [r1,r2,r3,r4,r5,r6,r7,r8,r9,r10,r11,r12,r1t,r3t,r111,r333]);
index = find(r10>=0); r10 = r10(index);r1 = r1(index);r2 = r2(index);r3 = r3(index);r4 = r4(index);r5 = r5(index);r6 = r6(index);r7 = r7(index);r8 = r8(index);r9 = r9(index);r11 = r11(index);r12 = r12(index);r111 = r111(index);r333 = r333(index);r1t = r1t(index);r3t = r3t(index);.....r12 = r12(index);r111 = r111(index);r333 = r333(index);r1t = r1t(index);r3t = r3t(index);