Hi,

I have 2 questions about geqr2.h:

1) a general question:

for example: https://github.com/langou/latl/blob/mas ... eqr2.h#L69

A[i] is the value of the array corrisponding to the shortest dimension of the matrix A. So, if for example, the shortest dimension of A is the rows number, A[i], as far as I understood, is the value in the i-th row.

I read here: https://github.com/langou/latl/blob/mas ... latl.h#L25 that matrices are implemented as pointers to column-major contiguous arrays. But to which colum of the matrix this i-th row of A[i] (in case m=min(n.m)) belongs to?

I do not understand how the columns (arrays) of a matrix are identified.

For example: in https://github.com/langou/latl/blob/mas ... emv.h#L123

for(j=0;j<n;j++) {

temp=alpha*x[jx];

for(i=0;i<m;i++) {

y[i]+=temp*A[i];

}

}

temp * A[i] is added to the i-th element of the array y . And for all n columns (arrays) of the matrix A[i]

But how to identify a specific element A[j][i] of matrix A?

2) Could you please explain me why (the logic behind it) here: https://github.com/langou/latl/blob/mas ... eqr2.h#L68

every single value of the matrix B, which is equal the matrix A (https://github.com/langou/latl/blob/mas ... eqr2.h#L65), is added first to the column length of the matrix and then added to the iteration counter i https://github.com/langou/latl/blob/mas ... eqr2.h#L74 ?

Looking forward to your kind explanation.

Kind Regards.

Marco