monsiw/mpi-histogram

TODO

Using the MPI library, write a program that calculates a histogram for a given string of data x[1], x[2], x[3], ...x[k] and threshold values A[1], A[2], ...A[N] (k >> N).
A histogram is an array H[1...N] with the property that H[i] is the number of x such that A[i-1] <= x < A[i] for i = 2, ..., N and H[1] is equal to the number of values of x satisfying the condition x < A[1].

The parallel histogram computation is performed by N sorting processes SEG(1...N), the main process P and the statistical process STAT. Process P sends threshold values from table A to the sorting processes so that A[i] goes to SEG[i], and then sends a string of x values to SEG[1]. After sending the last value, process P sends an end signal and receives results from the STAT process. Each sorting process checks whether the received x value is less than its threshold value. If so, it sends a signal to the STAT process, otherwise it passes x to the next SEG process. The STAT process counts the received signals in the H table, which it finally sends to the P process.