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

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)[phone];
    d = (8*10^7)*(v0(j).^2)-(4*10^19)*sqrt(3)-157705560;
    e = (4*10^6)*(v0(j).^2)[phone];    
    th (i,j) = vpasolve((a*h^4)+(b*h^3)+(f*h^2)+(d*h)-(e),h,[tp t1]);
    t1 = 0; 
    end
end

[Jan]

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)[phone];

f = -2e10 * c(i) * sqrt(3) - 4e8 * v0(j) .^ 2 - 981e5 * c(i) + 36460944400;

[Muhammed AlSubhi]

Thank you for the hint, I just copied the code from maple and has no chance to edited the code.

Answer 1

[Birdman]

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)[phone];
    d = (8*10^7)*(v0(j).^2)-(4*10^19)*sqrt(3)-157705560;
    e = (4*10^6)*(v0(j).^2)[phone];
    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

[Muhammed AlSubhi]

With the code you just gave me. The answer always the same, if I tried with just one value in different code it gave me a different answers but when I put the loop it did not.

[Birdman]

Then you should check your calculations in the loop. I also saw that the answer for every iteration in the loop results in eps, meaning that no solution is found. What is the different code you used?

[Muhammed AlSubhi]

clear all clc
syms h;
v0=200;
c = 2;
tp = 0.1;
t1 = ((log(1+0.0509683996*c*v0))/c);
assume(h, 'real')
a = (1*10^10)*c^2;
b = 21962000000*c;
f = (-2*10^10)*c*sqrt(3)-(4*10^8)*(v0^2)-98100000*c+36460944400;
d = (8*10^7)*(v0^2)-(4*10^10)*sqrt(3)[phone];
e = -(4*10^6)*(v0^2)[phone];
th = vpasolve(a*h^4+b*h^3+f*h^2+d*h+e,h, [tp t1]);

[Birdman]

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)[phone];
    d = (8*10^7)*(v0(j).^2)-(4*10^10)*sqrt(3)-157705560;
    e = -(4*10^6)*(v0(j).^2)[phone];
    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

[Muhammed AlSubhi]

it did work thank you very much :) How can I plot c vo and th in a 3rd plot?