m = gjp (m, k[, l]) m: matrix; k, l: row- and column-index of pivot, l defaults to k. Gauss-Jordon pivot as defined in Bard, Y.: Nonlinear Parameter Estimation, p. 296, Academic Press, New York and London 1974. In the pivot column, this seems not quite the same as the usual Gauss-Jordan(-Clasen) pivot. Bard gives Beaton, A. E., 'The use of special matrix operators in statistical calculus' Research Bulletin RB-64-51 (1964), Educational Testing Service, Princeton, New Jersey as a reference, but this article is not easily accessible. Another reference, whose definition of gjp differs from Bards by some signs, is Clarke, R. B., 'Algorithm AS 178: The Gauss-Jordan sweep operator with detection of collinearity', Journal of the Royal Statistical Society, Series C (Applied Statistics) (1982), 31(2), 166--168.
Package: optim