Write a function called sum_rows

Write a function called sum_rows that takes a matrix as input argument

(the function does not have to check the format of the input) and returns

a vector as an output argument. The elements of the vector are the

sums of the elements of the rows of the input matrix. Note that the built-in

MATLAB function sum returns the sum of the columns.

[Walter Roberson]

Okay, I have done as you have commanded. What next ?

[Stephen23]

https://web.archive.org/web/20211210080416/https://www.mathworks.com/matlabcentral/answers/1603360-write-a-function-called-sum_rows

Answer 1

[Abolfazl Chaman Motlagh]

sum function get dim (dimension which summuation operate on it) as second arguments.

so just use :

sum(A,2)

a function :

function x=sum_(A)
x=sum(A,2);
end

[Walter Roberson]

Let us test:

A = [1 2 3; 4 5 6]

A = 2×3

1 2 3 4 5 6

sum_(A)

ans = 2×1

6 15

function x=sum_(A)
x=sum(A,2);
end

Was a vector returned? Yes.

Does the vector equal the sum of the rows? Yes.

Is the function named sum_rows? No.

Is it reasonable to expect that volunteers will give exact solutions to homework questions? No.

Is it reasonable for a volunteer to show the technology the poster needs, assuming that the poster will adapt the ideas and use them as needed? Yes.

[John D'Errico]

Please do not do student homework assignments for them. This does not help the student, even if they seem grateful. All the student learns is they can use Answers as a way to do their homework for them. I would point out that the poster has posted two obvious homework assignment questions. (I closed the other.) If not discouraged, they will continue to post their entire assignments.