Q. Concurrently read exclusively write?
It's one of the models based on PRAM. In this model, processors access the memory location simultaneously for reading whereas exclusively for writing operations. In the algorithm that uses CREW model of computation n2 number of processors have been connected in form of a two dimensional array of size n x n.
Algorithm Matrix Multiplication using CREW
Input// Two Matrices M1 and M2
For I=1 to n //Operation performed in PARALLEL
For j=1 to n //Operation performed in PARALLEL
{
Oij = 0;
For k=1 to n
Oij = Oij + M1ik * M2kj
End For
}
End For
End For
The complexity of CREW based algorithm is O(n).