MATLAB: Compute triple summation for the homework

loopingsummation

hello guys

I have need to compute the following summation for my homework. Any hint or pseudo code would be helpful. Thanks.

Edit – "p" is a vector containing numbers and p(x) refers to the element position in that vector and "y" is a symbol

Best Answer

Since y is a symbol, you will need to use the Symbolic Toolbox.

You might be tempted to use symsum() for this, but symsum has the limitation that symbolic variables cannot be used for indexing of arrays.

So... ndgrid, calculate the formula for each point, and then sum() along the dimensions until you get a scalar result.

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MATLAB: Sigma notation – difference of individual vector values, for loop or symsum

I think you really need to read the basic tutorials for MATLAB, because this is about as basic as you can get.

If you subtract two vectors, x and y, the result will be the difference you are trying to create, right? Thus ...

x - y

Now, can you square those elements? Of course. So you might do this ...

(x-y).^2

That squares each element of the difference. Note that I carefully used a .^ operator there. That is very important. If you don't understand why, then see my first comment. READ THE MANUAL!

How do you sum a vector? Hint:

help sum

So try this ...

sum((x-y).^2)

Finally, you need to divide by the number of elements. So to wrap it all up, you might do this...

M = numel(x);
MSE = sum((x-y).^2)/M;

If you already know the length of those vectors as M, you need not do the first line there.

But really, you need to do some basic reading. You will gain in the end, by not having to ask basic questions for everything you do. There are also some great books out there to teach you MATLAB. And when you see a problem that is too complex for you to handle, break it into small pieces. Solve each part, looking towards the solution that you need, as I did above.

MATLAB: If y(i) contain 5 values such as 1,2,3,4,5. Then i want to sum all the values with a single command but i can’t solve this problem. Please help me out, the code is given below.

y = 1:5;
z = sum(y)

Best Answer

Related Solutions

MATLAB: Sigma notation – difference of individual vector values, for loop or symsum

MATLAB: If y(i) contain 5 values such as 1,2,3,4,5. Then i want to sum all the values with a single command but i can’t solve this problem. Please help me out, the code is given below.

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