top button
Flag Notify
    Connect to us
      Site Registration

Site Registration

Which order of loops is fastest in matrix multiplication and why ?

0 votes
448 views 
for(i=0;i<n;i++)
  for(j=0;j<n;j++)
     for(k=0;k<n;k++)
        C[i][j]+=A[i][k]*B[k][j];

In this algorithm, there are 6 combinations of loops : the one given above is ijk. The others are ikj,jki,jik,kij and kji. Which one executes the fastest and why?

posted Jun 29, 2016 by anonymous

Looking for an answer?  Promote on:
Facebook Share Button Twitter Share Button LinkedIn Share Button

Similar Questions
0 votes
Best way to find min of square of difference sub-matrices of a matrix to another matrix

suppose 

A(n,m) = 
1 2 3         
4 5 6                            
7 8 9

and 

B(p, q) = 
1 1
1 1

What is best method to find min of square of difference of sub-matrices of A and B e.g.

sub-matrices of A = 

1 2    |     2 3   |    4 5    |   5 6
3 4    |     5 6   |    7 8    |   8 9

Difference of first sub-matrix of A with B = 

(1-1)  (2-1)    = |     0 1
(3-1)  (4-1)      |     2 3

sum of square of elements = 0*0 + 1*1 + 2*2 + 3*3 = 14

similar steps for other sub-matrices of A

Please suggest looking for an alternate method or algorithm which has time complexity less than O(n*m*p*q)

+3 votes
Matrix multiplication using C/C++?

Say we have two matrix of m*n and n*t.
Any sample code in C/C++ along with the algorithm would be helpful.

...