Unable to perform assignment because the left and right sides have a different number of elements.

clear all 
close all
clc
t=[0:0.5:20];
ip=zeros(12,22)
q=0.25;
Vp=0.25;
p0=0.25;
S=0.25;
alpha=0.25;
d=0.25;
dabs=0.25;
t_p=0.25;
for n=1:length(ip)
ip(n)=(q*Vp*p0*S)/(alpha*d)*(exp(-alpha*Vp*(t-t_p))-exp(-alpha*dabs));
ipp=ip(n);
ipf=fft(ipp);
end 

Answer 1

[Image Analyst]

Watch:

clear all
close all
clc
t=[0:0.5:20];
ip=zeros(12,22)

ip = 12×22

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

q=0.25;
Vp=0.25;
p0=0.25;
S=0.25;
alpha=0.25;
d=0.25;
dabs=0.25;
t_p=0.25;
for n=1:length(ip)
    thisTerm = (q*Vp*p0*S)/(alpha*d)*(exp(-alpha*Vp*(t-t_p))-exp(-alpha*dabs))
    whos thisTerm
    ip(n)= thisTerm;
    ipp=ip(n);
    ipf=fft(ipp);
end

thisTerm = 1×41

0.0048 0.0028 0.0009 -0.0009 -0.0027 -0.0044 -0.0061 -0.0077 -0.0093 -0.0108 -0.0123 -0.0137 -0.0151 -0.0164 -0.0177 -0.0190 -0.0202 -0.0214 -0.0225 -0.0237 -0.0247 -0.0258 -0.0268 -0.0278 -0.0287 -0.0296 -0.0305 -0.0314 -0.0322 -0.0331

  Name          Size            Bytes  Class     Attributes

  thisTerm      1x41              328  double              

Unable to perform assignment because the left and right sides have a different number of elements.

You can't fit 41 numbers into a slot meant for 1. Perhaps you meant this:

clear all
close all
clc
t=[0:0.5:20];
ip=zeros(12,22)
q=0.25;
Vp=0.25;
p0=0.25;
S=0.25;
alpha=0.25;
d=0.25;
dabs=0.25;
t_p=0.25;
for n = 1 : length(t)
    this_t = t(n);
    thisTerm = (q*Vp*p0*S)/(alpha*d)*(exp(-alpha*Vp*(this_t-t_p))-exp(-alpha*dabs));
    ip(n)= thisTerm;
    ipp=ip(n);
    ipf=fft(ipp);
end