Sum consecutive groups of elements of an array

Question

Consider the array

A = [x1,x2,x3,...,xn]

Can you then in an easy way add two consecutive numbers in the array together in Matlab, such that you get:

B = [x1+x2, x3+x4,...]

Note that the each element only appears in one sum.

Answer 1

With sum and reshape -

B = sum(reshape(A,2,[]),1)

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With interp1 based on this -

nA = numel(A);
start = 1/(2*nA-2);
stop = 1 - start;
B = 2*interp1( linspace(0,1,nA), A,linspace(start,stop,nA/2))

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If playing code-golf, vec2mat from Communications System Toolbox could be used -

B = sum(vec2mat(A,2),2)

Or even more compact -

B = sum(vec2mat(A,2)')