How to Make a function accept vector inputs

function Ml = myseries(t)
n=0;
while (n<10)
  Ml = sum(t.^n/(gamma(n + 1)));
  n = n+1;
end

The above code runs well as long as the input variable is a scalar; for vectorized inputs, it fails. What might be wrong?

[Azzi Abdelmalek]

What "It fails" means? is there any error message?

[John D'Errico]

It isn't a question of MAKING it accept vector input. ANY function can always accept vector inputs. The issue is your code, making it work with vectors.

[Ben]

sum(t.^n/(gamma(n + 1))) needs to have a . before the /

[Walter Roberson]

./ would only be needed if the right hand side, gamma(n+1) was a vector or matrix, but in this context it is a scalar.

Answer 1

[Youssef Khmou]

You did not specify how the output should be , 1x1 or Nx1 , you can try this way :

 function Ml = myseries(t)
n=0;
ctr=1;
while (n<10)
  Ml(ctr) = sum(t.^n/(gamma(n + 1)));
  n = n+1;
  ctr=ctr+1;
end

Answer 2

[Walter Roberson]

Your current code overwrites all of Ml each time through the "while" loop, and so is unlikely to be doing what you want.

for n = 0 : 9
  Ml(n,:) = sum(t.^n/(gamma(n + 1)));
end

[Chuzymatics Chuzymatics]

Error Message: ??? Subscript indices must either be real positive integers or logicals.

[Youssef Khmou]

Just a small correction, @Walter, the index must start at 1.

[Walter Roberson]

Right, sorry,

for n = 0 : 9
  Ml(n+1,:) = sum(t.^n/(gamma(n + 1)));
end

[Chuzymatics Chuzymatics]

I am proud to belong to this community; you all are legends. Many thanks

Answer 3

[Image Analyst]

I think you can to what you want to do with one of these functions. Not sure what you want to do so pick one:

function theSum = myseries(t)
  % Vectorized method.
  n = 1:length(t);
  theSum = sum(t.^n ./ (gamma(n + 1)));

function theSum = myseries(t)
  % For loop method.
  theSum = 0;
  for n = 1 : length(t)
    theSum = theSum + t(n)^n ./ gamma(n + 1);
  end

This does something completely different than the other two answers but I think is what you were actually intending, which is trying to sum a series.

[Youssef Khmou]

i think the output should be a vector , if it was not the case, then a simple "sum(.....)" should suffice .

[Image Analyst]

I'm not so sure. It looks like he's trying to sum a series, and that would give a single summed value. I think he wants the sum of the first 10 terms of t(n)^n/gamma(n+1). A 10 element array t is passed in and n goes from 1 to 10. At least that's how I interpret it. Why do you think he wants a vector?

[Youssef Khmou]

it is guess, like i explained, if it was not a vector, no need for a question, a simple "sum(quantity)" is fine .

[Image Analyst]

Well he accepted your interpretation so I guess you were right. The Ml(2) was the sum of terms 1 and 2, the Ml(3) was the sum of terms 1, 2, and 3, and the element Ml(N) was term1 + term2 + term3 + term4 +....+termN. I thought he wanted just one sum - the sum of terms 1 through term N - not N sums, but I guess I was wrong.

[Youssef Khmou]

ok