MATLAB: How to add 2( two) function

MATLAB

dear Matlab I have 2 functions

q1 = @(p,T, bhp) WI .* (rho(p(w1),T(w1))./mu(p(w1),T(w1))) .* (p_conn(bhp,bhT)-p(w1));

q2 = @(p,T, bhp)-WI .* (rho(p(w2),T(w2))./mu(p(w2),T(w2))) .* (p_conn(bhp,bhT)-p(w2));

how to add that 2 function.I try

q_conn = q1+q2;

i got error

Undefined operator '+' for input arguments of type 'function_handle'.

Best Answer

Hi vaya putra

This error comes out because you are basically adding two "functions". What you want to do is probably adding two functions "output"

So, you should make another function which takes inputs and feed them to each function and add the output

this is an example.

 q1 = @(a,b) a+b;
 q2 = @(a,b) a*b;
 q3 = @(a,b) q1(a,b) + q2(a,b);

for your code, this might help

 q_conn = @(p,T, bhp) q1(p,T, bhp)+q2(p,T, bhp)

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MATLAB: Optimize a 2 variable function

I needed to parameterise your V equation for it to work with the Optimization Toolbox routines:

% % % p(1) = a,    p(2) = b;
V = @(p) -(26*(2000*cos((pi*p(1))/180) + (sin((pi*(p(1) + 45))/180)*((2600000*cos((pi*(p(1) + p(2)))/180)*(2^(1/2)/2 + (cos((pi*(p(1) + p(2)))/180)*sin((pi*(p(1) + 45))/180))/sin((pi*p(2))/180)))/(cos((pi*p(1))/180)^2*(cos((pi*(p(1) + p(2)))/180)*sin((pi*p(1))/180) - sin((pi*(p(1) + p(2)))/180)*cos((pi*p(1))/180))) + (2600000*cos((pi*p(1))/180)*sin((pi*(p(1) + 45))/180))/(cos((pi*(p(1) + p(2)))/180)*sin((pi*p(2))/180)*(cos((pi*(p(1) + p(2)))/180)*sin((pi*p(1))/180) - sin((pi*(p(1) + p(2)))/180)*cos((pi*p(1))/180)))))/((1300*(2^(1/2)/2 + (cos((pi*(p(1) + p(2)))/180)*sin((pi*(p(1) + 45))/180))/sin((pi*p(2))/180))^2)/cos((pi*p(1))/180)^3 + (1300*sin((pi*(p(1) + 45))/180)^2)/(cos((pi*(p(1) + p(2)))/180)*sin((pi*p(2))/180)^2) + 8085710131136235/4398046511104)))/(3*cos((pi*(p(1) + p(2)))/180)*sin((pi*p(2))/180)) - (26*((2^(1/2)*((2600000*cos((pi*(p(1) + p(2)))/180)*(2^(1/2)/2 + (cos((pi*(p(1) + p(2)))/180)*sin((pi*(p(1) + 45))/180))/sin((pi*p(2))/180)))/(cos((pi*p(1))/180)^2*(cos((pi*(p(1) + p(2)))/180)*sin((pi*p(1))/180) - sin((pi*(p(1) + p(2)))/180)*cos((pi*p(1))/180))) + (2600000*cos((pi*p(1))/180)*sin((pi*(p(1) + 45))/180))/(cos((pi*(p(1) + p(2)))/180)*sin((pi*p(2))/180)*(cos((pi*(p(1) + p(2)))/180)*sin((pi*p(1))/180) - sin((pi*(p(1) + p(2)))/180)*cos((pi*p(1))/180)))))/(2*((1300*(2^(1/2)/2 + (cos((pi*(p(1) + p(2)))/180)*sin((pi*(p(1) + 45))/180))/sin((pi*p(2))/180))^2)/cos((pi*p(1))/180)^3 + (1300*sin((pi*(p(1) + 45))/180)^2)/(cos((pi*(p(1) + p(2)))/180)*sin((pi*p(2))/180)^2) + 8085710131136235/4398046511104)) + (cos((pi*(p(1) + p(2)))/180)*(2000*cos((pi*p(1))/180) + (sin((pi*(p(1) + 45))/180)*((2600000*cos((pi*(p(1) + p(2)))/180)*(2^(1/2)/2 + (cos((pi*(p(1) + p(2)))/180)*sin((pi*(p(1) + 45))/180))/sin((pi*p(2))/180)))/(cos((pi*p(1))/180)^2*(cos((pi*(p(1) + p(2)))/180)*sin((pi*p(1))/180) - sin((pi*(p(1) + p(2)))/180)*cos((pi*p(1))/180))) + (2600000*cos((pi*p(1))/180)*sin((pi*(p(1) + 45))/180))/(cos((pi*(p(1) + p(2)))/180)*sin((pi*p(2))/180)*(cos((pi*(p(1) + p(2)))/180)*sin((pi*p(1))/180) - sin((pi*(p(1) + p(2)))/180)*cos((pi*p(1))/180)))))/((1300*(2^(1/2)/2 + (cos((pi*(p(1) + p(2)))/180)*sin((pi*(p(1) + 45))/180))/sin((pi*p(2))/180))^2)/cos((pi*p(1))/180)^3 + (1300*sin((pi*(p(1) + 45))/180)^2)/(cos((pi*(p(1) + p(2)))/180)*sin((pi*p(2))/180)^2) + 8085710131136235/4398046511104)))/sin((pi*p(2))/180)))/(3*cos((pi*p(1))/180)^2) - (539047342075749*((2600000*cos((pi*(p(1) + p(2)))/180)*(2^(1/2)/2 + (cos((pi*(p(1) + p(2)))/180)*sin((pi*(p(1) + 45))/180))/sin((pi*p(2))/180)))/(cos((pi*p(1))/180)^2*(cos((pi*(p(1) + p(2)))/180)*sin((pi*p(1))/180) - sin((pi*(p(1) + p(2)))/180)*cos((pi*p(1))/180))) + (2600000*cos((pi*p(1))/180)*sin((pi*(p(1) + 45))/180))/(cos((pi*(p(1) + p(2)))/180)*sin((pi*p(2))/180)*(cos((pi*(p(1) + p(2)))/180)*sin((pi*p(1))/180) - sin((pi*(p(1) + p(2)))/180)*cos((pi*p(1))/180)))))/(43980465111040*((1300*(2^(1/2)/2 + (cos((pi*(p(1) + p(2)))/180)*sin((pi*(p(1) + 45))/180))/sin((pi*p(2))/180))^2)/cos((pi*p(1))/180)^3 + (1300*sin((pi*(p(1) + 45))/180)^2)/(cos((pi*(p(1) + p(2)))/180)*sin((pi*p(2))/180)^2) + 8085710131136235/4398046511104));

Since you want to optimise it and the Optimization Toolbox functions minimise it, negating it produced a maximum. (That explains the minus sign.)

The code for the optimisation is:

A = [1 1];                          % Constraints

b = 90;                             % Constraints
[angs, fval] = fmincon(V, [1 1]', A, b)
asum = angs(1) + angs(2)            % Check

The A and b arguments are the equivalent of: (a + b) <= 90. The asum statement simply checks to see that the constraint was met.

The optimisation results are:

angs =
     -93.3393e+000
     180.0000e+000
fval =
    -694.1977e+009
asum =
      86.6607e+000

I negated V to get the maximum, so in reality fval = 694.1977e+009.

Since the solver uses the Jacobian to find the minimum of the function and reported:

Local minimum possible. Constraints satisfied.
fmincon stopped because the size of the current step is less than
the default value of the step size tolerance and constraints are 
satisfied to within the default value of the constraint tolerance.

the constraints on the derivatives were satisfied automatically.

MATLAB: How to make loop

wc(1).W1 = W(1).cells ;
wc(1).W2 = W(2).cells ;

Best Answer

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