function handle in a loop

Hello,

I have the following objective function in my optimization matlab function block

   if f_lag > 0                % decision braking or driving mode

     fun =@(x) (A/SOC_1)*(b(1))^2+(A/SOC_2)*(x(2))^2+(A/SOC_3)*(x(3))^2+(A/SOC_4)*(x(4))^2+d_delay_1-(SW_1+x(5))+d_delay_2-(SW_2+x(6))+d_delay_3-(SW_3+x(7))+d_delay_4-(SW_4+x(8));

      
   else

      fun =@(x) ((B*M_reg_1)/SOC_1)*(1/(x(1))^2)+((B*M_reg_2)/SOC_2)*(1/(x(2))^2)+((B*M_reg_3)/SOC_3)*(1/(x(3))^2)+((B*M_reg_4)/SOC_4)*(1/(x(4))^2)+d_delay_1-(SW_1+x(5))+d_delay_2-(SW_2+x(6))+d_delay_3-(SW_3+x(7))+d_delay_4-(SW_4+x(8));
   end
   

but because of code generation simulink/matlab, doesnt allow the function handles in the if loop.

Can someone help me what to do?

would be very glad, thank you!

Answer 1

[Walter Roberson]

Provided that the two calculations return the same size of values, and provided that neither calculation ever returns inf or nan, then the general form

if condition
  f = @(x) expression1
else
  f = @(x) expression2
 end

Can be rewritten as

f = @(x) (condition).*expression1 +
(~condition).*expression2

This is seldom the most efficient approach. Typically it would be more efficient to create both function handles and later test which one should be used.

[Sarah Kern]

Thank you very much, so like this?

f =@(x)  (f_lag == 1).*(A/SOC_1)*(x(1))^2+(A/SOC_2)*(x(2))^2+(A/SOC_3)*(x(3))^2+(A/SOC_4)*(x(4))^2+d_delay_1-(SW_1+x(5))+d_delay_2-(SW_2+x(6))+d_delay_3-(SW_3+x(7))+d_delay_4-(SW_4+x(8));

  + (f_lag == -1).*((B*M_reg_1)/SOC_1)*(1/(x(1))^2)+((B*M_reg_2)/SOC_2)*(1/(x(2))^2)+((B*M_reg_3)/SOC_3)*(1/(x(3))^2)+((B*M_reg_4)/SOC_4)*(1/(x(4))^2)+d_delay_1-(SW_1+x(5))+d_delay_2-(SW_2+x(6))+d_delay_3-(SW_3+x(7))+d_delay_4-(SW_4+x(8));

It wont let me create both function handles, that's what I tried before.

[Walter Roberson]

That code looks plausible.

It will let you create both function handles: just store them in different variables and invoke the appropriate one. You might even be able to store them in a cell array and index that at (f_lag+3)/2

Answer 2

[Sarah Kern]

Thank you very much, so like this?

f =@(x)  (f_lag == 1).*(A/SOC_1)*(x(1))^2+(A/SOC_2)*(x(2))^2+(A/SOC_3)*(x(3))^2+(A/SOC_4)*(x(4))^2+d_delay_1-(SW_1+x(5))+d_delay_2-(SW_2+x(6))+d_delay_3-(SW_3+x(7))+d_delay_4-(SW_4+x(8));
  + (f_lag == -1).*((B*M_reg_1)/SOC_1)*(1/(x(1))^2)+((B*M_reg_2)/SOC_2)*(1/(x(2))^2)+((B*M_reg_3)/SOC_3)*(1/(x(3))^2)+((B*M_reg_4)/SOC_4)*(1/(x(4))^2)+d_delay_1-(SW_1+x(5))+d_delay_2-(SW_2+x(6))+d_delay_3-(SW_3+x(7))+d_delay_4-(SW_4+x(8));

It wont let me create both function handles, that's what I tried before.