Assignment has more non-singleton rhs dimensions than non-singleton subscripts

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clear all clc
syms h;
v0=150:10:230;
c = [1 2 5 6 10 15 20 30 40];
th = zeros(length(v0), length(c));
tp = 0.1;
for i = 1:length(c)
for j = 1:length(v0)
t1 = (log(1+0.0509683996*c(i)*v0(j)))/c(i);
assume(h, 'real')
a = 1*10^10*c(i).^2;
b = 21962000000*c(i);
f = (-2*10^10)*c(i)*sqrt(3)-(4*10^8)*(v0(j).^2)-98100000*c(i)+36460944400;
d = (8*10^7)*(v0(j).^2)-(4*10^19)*sqrt(3)-157705560;
e = (4*10^6)*(v0(j).^2)+88400962361;
th (i,j) = vpasolve((a*h^4)+(b*h^3)+(f*h^2)+(d*h)-(e),h,[tp t1]);
t1 = 0;
end
end
  2 个评论
Jan
Jan 2018-4-16
编辑:Jan 2018-4-16
Please post the complete error message, which mentions also, in which line the error occurs. This is better than letting the readers guess this important detail.
By the way, -2*10^10 is a multiplication and an expensive power operation, while -2e10 is a cheap constant. Compare the readability:
f = (-2*10^10)*c(i)*sqrt(3)-(4*10^8)*(v0(j).^2)-98100000*c(i)+36460944400;
f = -2e10 * c(i) * sqrt(3) - 4e8 * v0(j) .^ 2 - 981e5 * c(i) + 36460944400;
Muhammed AlSubhi
Muhammed AlSubhi 2018-4-16
Thank you for the hint, I just copied the code from maple and has no chance to edited the code.

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采纳的回答

Birdman
Birdman 2018-4-16

The output of vpasolve seems to be returning empty solutions. You can detect if the solutions are empty and assign an eps value instead but it seems all of your solutions return empty ones. That has to do something with your equation. Try this:

syms h;
v0=150:10:230;
c = [1 2 5 6 10 15 20 30 40];
th = zeros(length(v0), length(c));
tp = 0.1;
for i = 1:length(c)    
    for j = 1:length(v0)    
    t1 = (log(1+0.0509683996*c(i)*v0(j)))/c(i);    
    assume(h, 'real')    
    a = 1*10^10*c(i).^2;
    b = 21962000000*c(i);
    f = (-2*10^10)*c(i)*sqrt(3)-(4*10^8)*(v0(j).^2)-98100000*c(i)+36460944400;
    d = (8*10^7)*(v0(j).^2)-(4*10^19)*sqrt(3)-157705560;
    e = (4*10^6)*(v0(j).^2)+88400962361;
    res=vpasolve((a*h^4)+(b*h^3)+(f*h^2)+(d*h)-(e),h,[tp t1]);
    if isempty(res)
        th (i,j) = eps;%you need to assign a value, this is a very small one,eps=2.2e-16
    else
        th(i,j)=res;
    end
    t1 = 0; 
    end
end
  5 个评论
Birdman
Birdman 2018-4-16
This piece of code differs mathematically from the initial code. Use the following code to get the results you want:
syms h;
v0=150:10:230;
c = [1 2 5 6 10 15 20 30 40];
th = zeros(length(v0), length(c));
tp = 0.1;
for i = 1:length(c)
for j = 1:length(v0)
t1 = (log(1+0.0509683996*c(i)*v0(j)))/c(i);
assume(h, 'real')
a = 1*10^10*c(i).^2;
b = 21962000000*c(i);
f = (-2*10^10)*c(i)*sqrt(3)-(4*10^8)*(v0(j).^2)-98100000*c(i)+36460944400;
d = (8*10^7)*(v0(j).^2)-(4*10^10)*sqrt(3)-157705560;
e = -(4*10^6)*(v0(j).^2)+88400962361;
res=vpasolve(a*h^4+b*h^3+f*h^2+d*h+e,h, [tp t1]);
if isempty(res)
th (i,j) = eps;%you need to assign a value, this is a very small one,eps=2.2e-16
else
th(i,j)=res;
end
t1 = 0;
end
end

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