Error using + Matrix dimensions must agree. Pleasee Helppp

if true
  % code
endRelRough = [0.00001 0.00005 0.0001 0.0002 0.0004 0.0006 0.0008 0.001 0.002 0.004 0.006 0.008 0.01 0.015 0.02 0.03 0.04 0.05];
ReL = [600:100:3900];
FCL = 64./ReL;
ReT = [[4e3:1e3:9e3] [1e4:1e4:9e4] [1e5:1e5:9e5] [1e6:1e6:9e6] [1e7:1e7:1e8]];
for i=1:length(RelRough)
  for j=length(ReT)
  FCT_old=1;
  residual=1;
  while residual>0
  FCT_new=1./(-2*log10((RelRough./3.7)+(2.51./(ReT*sqrt(FCT_old))))).^2 ;
  residual=abs(FCT_new-FCT_old);
  FCT_old=FCT_new
  end
  FCT(i,j)=FCT_old
  end
end

>> FCLT_kimhaote Error using + Matrix dimensions must agree.

Error in FCLT_kimhaote (line 10) FCT_new=1./(-2*log10((RelRough./3.7)+(2.51./(ReT*sqrt(FCT_old))))).^2 ;

Answer 1

[James Tursa]

The error message is very clear. The variables you are trying to add do not have compatible sizes. Specifically

>> size(RelRough)
ans =
     1    18
>> size(ReT)
ans =
     1    43
>> FCT_new=1./(-2*log10((RelRough./3.7)+(2.51./(ReT*sqrt(FCT_old))))).^2 ;
??? Error using ==> plus
Matrix dimensions must agree.

You need to fix your code so that the operation is compatible.

[Kim Hao Teong]

I dont think so. I think I have defined the values of the inputs as instructed

<<

>>

[Adam]

Clearly you haven't if you are getting different sized matrices to add together!

[Kim Hao Teong]

I dont even know what should I do now