What are Multigrid Algorithms?
Multigrid (MG) or multilevel algorithms are very fast solvers
used in numerical analysis (e.g. solution of partial
differential equations), physics (e.g. fluid dynamics,
Lattice Gauge Theory),
and computing (e.g. graphics with textures).
There is a good deal of overlap with
wavelet multiresolution techniques.
Some books on the topic are
here.