Subject: [ublas] ublas::vector and a "random access" container concept? And ublas::matrix.
From: jesseperla_at_[hidden]
Date: 2009-01-22 14:11:48
I have been writing a lot of generic code recently that needs to operate on
boost::array, std::vector, and ublas::vector
I have found the lack of operator[] for random element access to be a real
pain for writing generic code, and it seems to be inconsistent with the
others. I understand the rationale for not having operators[] on
ublas::matrix, to be discussed later, but why cannot operator() and
operator[] call the same code for ublas::vector? Am I missing something?
Right now my workaround is to use .begin() and then use the random access
iterator concept implemented by all of these iterators. But this is really
ugly for many cases.
For ublas::matrix. I am also having trouble writing generic code that works
for normal C 2D arrays and with boost::multi_array. Here,
boost::multi_array implements the [] operator which I assume passes back
either a value or an iterator depending on the dimension. The result is
that for both normal C and boost::multi_array, I can use the:
mycontainer[0][1] notation. Now, I understand why ublas::matrix relies on
the operator() for access, and why it is more efficient, but is there any
way to also implement [] operators in a similar way to multi_array (passing
back an iterator if called on the matrix and a value if called on the
matrix column/row iterator)? This would make generic code a lot easier to
write. Alternatively, is there an equivalent to the .begin() that works for
both data structures? The problem I have is that the 2D iterator concept
implemented by ublas::matrix is inconsistent with that implemented by
multi_array.
Thanks,
Jesse