Discover MakerZone

MATLAB and Simulink resources for Arduino, LEGO, and Raspberry Pi

Learn more

Discover what MATLAB® can do for your career.

Opportunities for recent engineering grads.

Apply Today

To resolve issues starting MATLAB on Mac OS X 10.10 (Yosemite) visit: http://www.mathworks.com/matlabcentral/answers/159016

How to find maximum value for 3 iterative variables.

Asked by Shantanu K on 7 Mar 2013

In this i have to do following operation mentioned:

Here value of a,b,z are changing continuously. For every value program will calculate value of 'y'.

It will become three dimensional array.

For entire these iterations i have to find out maximum value of 'y' and corresponding value of 'a' & 'b'.

I am facing one more problem, when i formulated array it was showing lot more zeros.

for p=1:6
      a=2*p;
      for q=1:6
          b=5*q;
            for z=1:100
                 k=z*z;
                 x=k*4+1;
                 y=a*x+b*k+1;
                 y(p,q,z)=y;
            end
        end
    end

6 Comments

Shantanu K on 7 Mar 2013
p=0;
q=0;
z=0;
for p=1:6
      for q=1:6
          for z=1:100
              a=2*p;
              b=5*q;
               k=z*z;
               x=k*4+1;
               y(p,q,z)=a*x+b*k+1;
          end
      end
  end

How to find maximum value of 'y' and get corresponding value of 'p' and 'q'?

Walter Roberson on 7 Mar 2013

Do you want the 'a' and 'b' (as you wrote the first time) or the 'p' and 'q' (as you write now) ?

Shantanu K on 7 Mar 2013

Thanks Walter for your help !

Shantanu K

Products

No products are associated with this question.

2 Answers

Answer by Andrei Bobrov on 7 Mar 2013
Edited by Andrei Bobrov on 7 Mar 2013
Accepted answer
max1 = [-inf 0 0 0];
for p=1:6
    for q=1:6
        for z=1:100
            a=2*p;
            b=5*q;
            k=z*z;
            x=k*4+1;
            k1 = a*x+b*k+1; 
            y(p,q,z) = k1;
            if k1 > max1(1), max1 = [k1,p,q,z]; end 
        end
    end
end

2 Comments

Walter Roberson on 7 Mar 2013

Re-using the variable "k" could be confusing to me.

Andrei Bobrov on 7 Mar 2013

Oh! Typo, thank you, Walter!

Corrected.

Andrei Bobrov
Answer by Walter Roberson on 7 Mar 2013

Before loop:

maxy = -inf;
a_at_max = -inf;
b_at_max = -inf;

then inside the loop, where you assign into y, test to see if the new value is greater than maxy, and if it is, record the a and b values

2 Comments

Shantanu K on 7 Mar 2013

I am not able to understand it sir, can you please elaborate?

then inside the loop, where you assign into y, test to see if the new value is greater than maxy, and if it is, record the a and b values This part i am not able to convert to program.

Walter Roberson on 7 Mar 2013
if y(p,q,z) > maxy
  %then update your record of which "a" and "b" values led to this maximum
end

Oh yes and remember to update maxy with the new maximum as well.

Hint: "update" means "do an assignment to"

Walter Roberson

Contact us