On 26/10/15 15:13, Patrick Alken wrote:
Yes. I’d be happy to look at redesign of the GSL containers. What’s
needed?
There was a discussion on gsl-discuss some time back, see:
https://www.sourceware.org/ml/gsl-discuss/2014-q2/
Gerard may have already done some work on this, or have some ideas on a
good starting point, so I suggest getting in touch with him too (cc'd).
I’d forgotten the detail of that discussion.
I can think of a way to change the gsl block/vector/matrix alloc
functions to be more efficient. In essence it is a pool allocator.
It would keep a record, for each power k of two up to some limit n, of
the number of blocks allocated for sizes 2^k to 2^{k+1} together with a
capacity (also a power of two) for blocks of that range. These would
form linked lists of allocated and unallocated blocks. Given a request
for a new block, if an unallocated one was available, it would be
allocated. Otherwise the capacity would be doubled. When a block is
freed, memory is only deallocated if no more than a quarter of capacity
is used or if no blocks are used.
This idea needs more input.
I can’t think of a good way to create gsl_vectors and the like in stack
memory. Of course, it is always possible to create a struct and
initialise it.
I also don’t know of a good, easy solution to the problem of constness.
--
John D Lamb
