MATLAB: I am trying to write a function but it will not work.

errorfunction

function [ absorption ] = solar_rad( nc,lat,t,I)
%Calculating absorbed solar radiation
%   Calculating the absorbed solar radiaiton as a function of time of
%   day and year, cloud cover, and latitude, using a time step of one hour.
%BEGIN
for I=1:365;
      for T=[0:24];
          t=T*3600;
      end
     delta=-23.45*(pi/180)*cosd(2*pi)/365*(I+9); %Declination 
     S=1357+45*cosd((2*pi)/365)*(I); %Solar constant
    for lat=0;
      sinh=max(sind(lat)*sind(delta)+cosd(lat)*cosd(delta)*cosd((2*pi/86400)*(t+43200)));
      m=1/sinh; %optical length
      Cext=0.128-0.0253*(log(m)); %Extinction
    end
    for h=asin(max(sind(lat)*sind(delta)+cosd(lat)*cosd(delta)*cosd((2*pi)/86400)*(t+43200)));
      i=(pi/2)-h; %angle of incidence
      j=asin(0.75*sin(i)); %angle of reflection
      r=0.5*abs((sin(i-j)^2/sin(i+j)^2)+(tan(i-j)^2)/(tan(i+j)^2)); %reflectance
    end
end
for nc=0:100;
      if h>0
      Insd=S*(exp(-Cext*m))*(sin(h))*(1-(0.71*nc)); %direct incoming solar radiation at sea level
      end
      if h<=0
      Insd=0;
      end
      for Insg=0.52*nc*Insd; %global radiation
      Q_sun=Insd*(1-r)+0.97*Insg; 
      end
end
[absorption]=solar_rad(0,0,t,I);
Whenever I run it I get this error message:
Error in solar_rad (line 7)
for I=1:365;
Output argument "absorption" (and maybe others) not assigned during call to "\\fs-home-k\home-005\osp42f\My
Documents\MATLAB\Programmes\solar_rad.m>solar_rad".

Best Answer

You don’t have any variable named ‘absorption’ on the left-hand side of any statement anywhere in your code for your ‘solar_rad’ function. It has to have a variable by that specific name assigned somewhere in your code or it will not return any value for that variable.
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