24 Jun
2010
24 Jun
'10
1:56 p.m.
On Thu, 24 Jun 2010, Barend Gehrels wrote:
Hi Jeremiah,
I react on this point only:
- Property maps are passed by copy; they are intended to be lightweight and using copies allows temporary property maps to be passed in.
I don't understand this. If I have a graph of one million vertices and even more edges, the property map (e.g. defining something for each vertex) is certainly not lightweight. Or do you mean other property maps?
The property map is not intended to own the data; thus, copying a property map is only a shallow copy and thus cheap. That is why classes such as iterator_property_map require a separate object for the actual data storage; that object is not copied when the property map is copied. -- Jeremiah Willcock