Why are i and j flipped?

[minhkhang1795]

Are there any reasons why i and j are flipped? I thought it should be a[ (i)*lda + (j) ] instead of the code below:

#define A(i,j) a[ (j)*lda + (i) ]

Example: Result of matrices a, b and cref (randomized integers):

// a
83.000000 86.000000 
77.000000 15.000000 
// b
93.000000 35.000000 
86.000000 92.000000 
// cref
10463.000000 8544.000000 
14284.000000 8803.000000 

[rayjan0114]

I got the same question!!

[marvin-Yu]

https://www.youtube.com/watch?v=PhjildK5oO8

[poemon1]

There explaination in the notes: ‘Create macros so that the matrices are stored in column-major order'