Merge two sorted vectors into a sorted vector

mergesorted.m
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If we have two individually sorted vectors "a" and "b" but they are not sorted with respect to each other and we want to merge them into vector "c" such that "c" is also a sorted vector. Then c=mergesorted(a,b) can be used.

This function most likely make difference for very large vectors (may be elements in million). On P-4 machine when length of "a" is 2 million and length of "b" is 2.5 million then c=mergesorted(a,b) is around 3 times faster than using MATLAB builtin function c=sort([a,b]).

testmergesorted.m
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A simple test program to that test "mergesorted" and builtin "sort" function and compare their performance.