How can i define with variable

COORD = [0 0;2 0;4 0;2 2;0 2]; 
CON = [2 1;3 2;3 4;2 4;4 1;4 5]; 

for a = 1:6
    i = CON(a,1);
    j = CON(a,2);
    COORD(j,1);
    COORD(i,1);
    dx = COORD(j,1)-COORD(i,1); 
    dy = COORD(j,2)-COORD(i,2); 
   
  lambdax(a) = dx ;
  lambday(a) = dy ;
    
end

for a = 1:6 
  
   K = [lambdax(a)^2  lambdax(a)*lambday(a) -lambdax(a)^2 -lambdax(a)*lambday(a);lambdax(a)*lambday(a) lambday(a)^2 -lambdax(a)*lambday(a) -lambday(a)^2;-lambdax(a)^2 -lambdax(a)*lambday(a) lambdax(a)^2 lambdax(a)*lambday(a);-lambdax(a)*lambday(a) -lambday(a)^2 lambdax(a)*lambday(a) lambday(a)^2]

end

Hello everyone, this is my script it is working now but i need K in the form of K(a) or K(b), if i write K(a) it is not working. How can i write like K(a)?

Answer 1

[Star Strider]

I still do not understand what you want to do, however it is straightforward to create ‘K’ as an anonymous function:

K = @(a) [lambdax(a).^2  lambdax(a)*lambday(a) -lambdax(a).^2 -lambdax(a).*lambday(a);lambdax(a).*lambday(a) lambday(a).^2 -lambdax(a).*lambday(a) -lambday(a).^2;-lambdax(a).^2 -lambdax(a).*lambday(a) lambdax(a).^2 lambdax(a).*lambday(a);-lambdax(a).*lambday(a) -lambday(a).^2 lambdax(a).*lambday(a) lambday(a).^2];

That should then produce whatever it is that you want from calling ‘K’ as a function.

See the documentation section on Anonymous Functions for details on how they work and how to use them.

I also vectorised ‘K’. See Array vs. Matrix Operations for those details.

.

[fatih ayça]

In my script there is 6 K but it defined last one to K, i want that i ve K(1),K(2)...K(6)

[Star Strider]

‘In my script there is 6 K but it defined last one to K, i want that i ve K(1),K(2)...K(6)’

I have absolutely no idea what that means.

I cannot go further without knowing what ‘lambdax’ and ‘lambday’ are. They need to be defined, regardless of whether they are functions or arrays.

[fatih ayça]

I editted again,lambdax and lambday has 6 different values. So there are 6 value for K, but this script define last one for K, i want call K with 6 different value. Sorry for my bad english.

[Star Strider]

It would be easiest to define ‘K’ as a cell array in the loop:

K{a} = [lambdax(a).^2  lambdax(a).*lambday(a) -lambdax(a).^2 -lambdax(a).*lambday(a);lambdax(a).*lambday(a) lambday(a).^2 -lambdax(a).*lambday(a) -lambday(a).^2;-lambdax(a).^2 -lambdax(a).*lambday(a) lambdax(a).^2 lambdax(a).*lambday(a);-lambdax(a).*lambday(a) -lambday(a).^2 lambdax(a).*lambday(a) lambday(a).^2];

Then to get the values for ‘K{1}’ for example:

K1 = K{1}

producing:

K1 =
     4     0    -4     0
     0     0     0     0
    -4     0     4     0
     0     0     0     0

and so for the rest.

[fatih ayça]

Thank you so much.

[Star Strider]

As always, my pleasure!