'Matrix dimensions must agree'

Hi, can someone please advise as to how to fix this error. Ive tried just using * or using dz(j) in the final68 sum (though I think the latter would have given me the wrong answer anyway) but its not fixing it. Fe68 is iron data form a model. I can contour a hydrothermal plume by plotting Fe68 against depth and longitude however below I am trying to quantify the plume into number in m^2 (dlong is longitude converted into meters).

dlong = 109079.92

anom68(find(Fe68<=0))=0
anom68(find(Fe>0))=1

for j=2:31
    dz(j)=abs(depth(j)-depth(j-1))
end

final68 = anom68.*dz(:).*dlong
sum(final68)

Thank you.

The error message just states 'matrix dimensions must agree', 'error in line 101 (final68 = anom68.*dz(:).*dlong)'.

Alexandra

[Stephen23]

@Alexandra: please edit your questions and give the entire error message. This means all of the red text.

[Star Strider]

Please provide more information, specifically the size results of the arrays used in your calculations. The row and column sizes of the matrices in you calculations must be the same.

[Alexandra Ridgway]

Hi Star, dlong is just one number while dz is 1x31. anomFe68 is 1x4429. Thanks for your help :) Alexandra

Answer 1

[Jan]

The error message means, that the number of elements of anom68 and dz differ, or at least they do not have the same size. Try this:

dbstop if error

Then run your code again until Matlab stops. Then type in the command window:

size(anom68)
size(dz(:))

If the sizes do not match, the elementwise multiplication .* is not possible. Based on provided information, a suggestion for improvement is not possible.

Note: Although runtime does not matter here, consider the MLint message, which appears in the editor: omit the find() command, which is not required but wastes time only:

   anom68(Fe68<=0) = 0
   anom68(Fe>0)    = 1