[R] how to find indices of particular array elements

[Jonathan Williams]

Dear R helpers,

I have a largish matrix (1300 x 1300) and I wish to find the row and column
numbers that identify particular elements whose values I know in advance
(for example, the row and column numbers for the maximum value of the
matrix).

I have looked in the help manual and found the functions 'row' and 'col' for
finding the indices of a matrix. But, I can't figure out how to use them to
obtain the indices of the matrix element with maximum value, despite over an
hour of trying!

Many thanks for your help,

Jonathan Williams