[chestervonwinch]

All of these examples are equivalent to least squares :)

[solinent]

Yeah, for the most part all of engineering is equivalent to least squares I'd say, there's always some non-linear optimization procedure that uses a norm^2 metric since it's so well studied and solved already. It's disappointing as a mathematician, but the rest of me is fine with it :)

[vecter]

How is PCA the same as least squares? I've always understood it as the eigendecomposition of the covariance matrix.