My code continuously giving this error( Error using ./ Matrix dimensions must agree. Error in Untitled14 (line 16) k = zeta*(w./wd); )

zeta = g * q;
j= 1-power(zeta,2);
wd = w*power(j,1/2);
r=w./wd;
k = zeta*r;
l=k*sin(wd*t);
m=cos(wdt) + l;
n= - zeta*w*t;
p = 1 - exp(n)*(m);
plot (p)

[Walter Roberson]

That line, k = zeta*(w./wd); does not appear in your posted code.

It is difficult for us to debug this without knowing the size() of each of the variables.

[arif hussain]

basically this is the full code and the problem in variable "r" r=w./wd; and cant we assume the maximum size of the variable?

filename = 'datacollect2.xlsx';
num = xlsread(filename,'B1:B60');
w = num/60;
N = length(num);
t = 1/w;
s = xlsread(filename,'B3:B3');
xt= s;
g = 1/N;
i = xt + num;
h = xt/ i ;
ln=@log;
q=ln(h);
zeta = g * q;
j= 1-power(zeta,2);
wd = w*power(j,1/2);
r=w./wd;
k = zeta*r;
l=k*sin(wd*t);
m=cos(wdt) + l;
n= - zeta*w*t;
p = 1 - exp(n)*(m);
plot (p)

filename = 'datacollect2.xlsx';
num = xlsread(filename,'B1:B60');
w = num/60;
N = length(num);
t = 1/w;
s = xlsread(filename,'B3:B3');
xt= s;
g = 1/N;
i = xt + num;
h = xt/ i ;
ln=@log;
q=ln(h);
zeta = g * q;
j= 1-power(zeta,2);
wd = w*power(j,1/2);
r=w./wd;
k = zeta*r;
l=k*sin(wd*t);
m=cos(wdt) + l;
n= - zeta*w*t;
p = 1 - exp(n)*(m);
plot (p)

[arif hussain]

Error using ./ Matrix dimensions must agree.

Error in Untitled14 (line 16) r=w./wd;

[arif hussain]

size of w is 60x1 double size of wd is 60x60 double

Answer 1

[Walter Roberson]

You are using the / operator in several places. In MATLAB, A/B is more or less the same as A * pinv(B) . 1/w where w is 60 x 1, gives you a 1 x 60 result. Likewise, h = xt/ i where i is 60 x 1, gives you a 1 x 60 result. You then end up working with this mix of 60 x 1 and 1 x 60 and you end up with trying to combine arrays in the wrong way.

>> 1/[2;4;3]
ans =
                         0                      0.25                         0

Notice the output is a row vector for a column vector divisor.

If you would need the answer [0.5; 0.25; 0.3333] (column vector, individual divisions) instead for this calculation, then you need to use the ./ operator