How can I make a 3d plot using 2 functions combined in 1 function?

Hi friends! I have the following problem.

I have written two separate functions with two separate input arguments: function1 with input argument x and function2 with input argument y. The two functions symbolise the profit of option 1 and 2.

In a new function I have combined function1 and function2 in just 1 function. The name of the function is total_return and sums the profit of function1 and 2. In the new function the profit of function1 is multiplied with a and the profit of function 2 is multiplied with 1-a. The new function therefore has the input arguments: a, x and y.

I would like to make a 3d plot (surf) with the variables: a, x and total_return.

So that makes:

surf(a,x,total_return(a,x,8.5)).

1: let's say, we make the last input variable of the total_return function 8.5 (=y).

2: in the workspace I have made a row vector of x (1x100) and a column vector of a (100x1).

When I compute the surf function I still get:

error using +

matrix dimensions must agree.

-->Referring to the part of the new function were I sum up the two profits in 1 profit, that 1 profit being: total_return. Something is clearly wrong here, but I can't figure it out.

I thinks something goes wrong with the computation of the two separate functions, those dimensions don't agree or something.

I would love to have some help with this. Thank you very much in advance. I am chemical student and struggling at the moment. I hope this explanation is elaborate enough for you. I am using matlab r2012b

Thanks,

Tjeerd

Entire function:

function [ total_return ] = total_return ( a,x,y ) %UNTITLED2 Summary of this function goes here % Detailed explanation goes here

h2_price = x;

cog_volumein = 12800;

cog_lhv = 18.39;

cog_energy_inlet = ((cog_lhv * cog_volumein)/1000);

loadfactor = 8500;

psa_eff = 0.775;

h2_contentcog = 0.59656;

h2_density = 0.0899;

h2_vfrexit = cog_volumein * psa_eff * h2_contentcog;

h2_mfrexit = h2_vfrexit * h2_density;

h2_lhv = 120;

h2_energy = h2_lhv * h2_mfrexit * loadfactor;

h2_value = h2_price * h2_mfrexit * loadfactor;

cog_volumeexit = cog_volumein-h2_vfrexit;

cog2_lhv = 25.16;

cog_energy_exitPSA = cog_volumeexit * cog2_lhv/1000;

elec_eff = 0.39;

cog_elecprod = cog_energy_exitPSA * elec_eff/3.6;

elec_price = 50.50;

cog_elprod_value = elec_price * cog_elecprod * loadfactor;

cog_price = 5.4;

cog_cost = cog_price * cog_energy_inlet * loadfactor;

h2_return = h2_value + cog_elprod_value - cog_cost;

wb2_value = cog_energy_inlet * y * loadfactor;

cog_cost = cog_price * cog_energy_inlet * loadfactor;

wb2_return = wb2_value - cog_cost;

return1 = a * h2_return;

return2 = (1 - a) * wb2_return;

total_return = return1 + return2;

end

Falling line:

total_return = return1 + return2;

[Jan]

Please show us the failing line and the dimensions of the variables. The debugger will help you to find them out.

[Tjeerd Luykx]

The falling line = total_return = return1 + return2;

I have denoted the entire function above. I hope this will make it easier, but unfortunately quite extensive