Adjacency matrix vs Adjacency list?

From: Robert Adams (fake_at_none.com)
Date: 02/09/04 

Date: Mon, 09 Feb 2004 00:12:55 GMT

When is it proper to use which ?
Am i correct in the assumption that the adjacency matrix must have way
shorter lookup-times(finding an element) especially for a large amount of
nodes, since it can simply be implemented as a "double array" i.e. no search
needed. For large amount of nodes the adjacency matrix should consume a lot
of memory.

Consider the Ford-Fulkersson method:
Which representation(adj.matrix or adj.list) provides for the fastest
execution of that algorithm ? Sure for large amounts of nodes an adj. matrix
representation would use up a lot of memory, but that wouldn´t affect
algorithm speed, if we have enough memory. So therefore , because of the
shorter lookup-times, adj.matrix matrix would be the best choice ?

Any (constructive) comments appreciated, i wan´t to sort out this matter :)