Trouble with my homework - Getting an error in my linear programming code requiring a double.

options=optimoptions(@linprog,'Algorithm','dual-simplex');
f=[110;220;250;140];
A=[2/3,1,5/8,5/6;0,1,6/5,3/4;0,1,1/2,0;0,0,0,1];
ub=[10000;150000;8000;7000];
lb=zeros(4,1);
[x,fval,exitflag,output,lambda] = ...
linprog((f,A,ub,[],[],lb,options)

Error using linprog

LINPROG requires the following inputs to be of data type double: 'UB'.

Error in ProfitMax (line 7)

linprog(f,A,ub,[],[],lb,options)

running the following to maximise profits

110x1 + 220x2 + 250x3 +140x4

on the following

2/3x1 + 1x2 + 5/8x3 + 5/6x4 <= 10000

0x1 + 1x2 + 6/5x3 + 3/4x4 <= 15000

0x1 + 1x2 + 1/2x3 + 0x4 <= 8000

0x1 + 0x2 + 0x3 + 1x4 <= 7000

And should I be using dual simplex or interior point - why does this matter?

[Image Analyst]

It looks like everything is a double except for the nulls. What are those supposed to be? Is it okay if they're null?

[Scott]

They were in the example code provided by the lecturer. If I delete them the error code changes to

Error using linprog

LINPROG requires the following inputs to be of data type double: 'beq'.

Error in ProfitMax (line 7)

linprog(f,A,ub,lb,options)

Answer 1

[Walter Roberson]

linprog((f,A,ub,[],[],lb,options)

You missed passing ub in. Your options are in the ub slot.

[Walter Roberson]

Note that you cannot pass values in any order you like. MATLAB does not look at the names of the variables you pass in to decide what function the parameter should have: MATLAB requires a very specific order:

f_Matrix, Linear_Inequality_A, Linear_Inequality_b, Linear_Equality_A, Linear_Equality_b, Lower_Bound, UpperBound, Initial_Guess, Options