# using summation within a function

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Giuseppe Battaglia am 13 Mär. 2016
Kommentiert: Walter Roberson am 11 Jul. 2021
I'm trying to compute something like this:
x=1:100
n=1:10
y=sum(x+n) (or any other f(x))
This only works if n and x have the same dimension as matrix, but what I'm after is to use to derive y =f(x) but so far I had no luck any help is wellcome
thanks
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Walter Roberson am 13 Mär. 2016
In a case like that, what size would you want y to come out as, and what values?

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### Antworten (1)

Dave Behera am 24 Mär. 2016
The x + n part will only work if they are the same dimension. Can you please describe in detail what you are referring to as 'derive y =f(x)'?
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Sa'adatu Abubakar am 10 Jul. 2021
I want to use the summation function inside the newtonRaphson algorithm, how can I express it I used symsum(f,k,a,b) but it dosnt work. Do I need to use for loop?
Walter Roberson am 11 Jul. 2021
sum(arrayfun(@f, a:b))
If f returns a non-scalar value then you might need
temp = arrayfun(@f, a:b, 'uniform', 0);
nd = ndims(temp{1});
y = sum(cat(nd+1, temp{:}),nd+1);

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