I have just read the following paper on Parallel
i have implemented this algorithm just to see what is the
And i have noticed that the serial algorithm is 8 times
than the merge function that you find in the serial mergesort
So 8 times slower, it's too slow.
It's better to use the
idea is simple:
Let's assume we want to merge sorted arrays X and Y.
Select X[m] median
element in X. Elements in X[ .. m-1] are less than or
equal to X[m].
Using binary search find index k of the first element in Y
Thus Y[ .. k-1] are less than or equal to X[m] as
well. Elements in X[m+1 .. ]
are greater than or equal to X[m] and Y[k .. ]
are greater. So merge(X, Y)
can be defined as concat(merge(X[ .. m-1], Y[ ..
k-1]), X[m], merge(X[m+1 .. ], Y[k .. ]))
now we can recursively in parallel
do merge(X[ .. m-1], Y[ .. k-1]) and
merge(X[m+1 .. ], Y[k .. ]) and then
And then you can continue to apply this method
Amine Moulay Ramdane.