MATLAB: Help solving an error

for loopsfunctions

Here is the code:
load PollutionData.txt;
array = PollutionData(:,1); %#ok<NODEF>
timearray = (0:.5:250);
timearray = reshape(timearray,[],1);
constant = reaeration(array);
array(3,:) = array(3,:) .* 0.001076; %conversion

array(6,:) = array(6,:) .* 0.0002778; %conversion
resultarray = deOxygen(array , timearray, constant);
plot(timearray(:,1) , resultarray(:,1))
return
function constant = reaeration(array)
constant = ((array(5,:) * array(3,:)) ^ 0.5) / (array(4,:) .^ 1.5);
return
function resultarray = deOxygen(array , timearray, constant)
resultarray = zeros(1,1000);
for a = (0:.5:250) 
resultarray(a) = (((array(6,:) * array(2,:)) / (constant - array(6,:))) * (exp(-array(6,:) * timearray(a) * 3600) - exp(-constant * timearray(a) * 3600))) + (array(1,:) * exp(-constant * timearray(a) * 3600));
end
return
I'm getting in error in the deOxygen function at the "resultarray(a) = (((…" portion. Also, the two following errors also appear:
Attempted to access timearray(0); index must be a positive integer or logical.
Error in myHW7 (line 15) resultarray = deOxygen(array , timearray, constant);
And I have no idea why. Any ideas?
Thanks

Best Answer

In ‘deOxygen’, define the ‘a’ vector first:
a = (0:.5:250);
then set the loop up as:
for k1 = 1:length(a)
and replace the ‘(a)’ subscripts with ‘(k1)’ subscripts (or whatever loop counter variable you choose). MATLAB does not allow subscripts to be negative, zero, or non-integers.
Also, I’m not sure what ‘a’ is doing. You don’t use it anywhere in ‘deOxygen’ that I can find.
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