Mercurial > hg > octave-lyh
diff scripts/polynomial/poly.m @ 10687:a8ce6bdecce5
Improve documentation strings.
author | Rik <octave@nomad.inbox5.com> |
---|---|
date | Tue, 08 Jun 2010 20:22:38 -0700 |
parents | 16f53d29049f |
children | 693e22af08ae |
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--- a/scripts/polynomial/poly.m +++ b/scripts/polynomial/poly.m @@ -18,11 +18,13 @@ ## <http://www.gnu.org/licenses/>. ## -*- texinfo -*- -## @deftypefn {Function File} {} poly (@var{a}) +## @deftypefn {Function File} {} poly (@var{a}) +## @deftypefnx {Function File} {} poly (@var{x}) ## If @var{a} is a square @math{N}-by-@math{N} matrix, @code{poly (@var{a})} ## is the row vector of the coefficients of @code{det (z * eye (N) - a)}, -## the characteristic polynomial of @var{a}. As an example we can use -## this to find the eigenvalues of @var{a} as the roots of @code{poly (@var{a})}. +## the characteristic polynomial of @var{a}. For example, +## the following code finds the eigenvalues of @var{a} which are the roots of +## @code{poly (@var{a})}. ## @example ## @group ## roots(poly(eye(3))) @@ -31,14 +33,14 @@ ## @result{} 1.00000 + 0.00000i ## @end group ## @end example -## In real-life examples you should, however, use the @code{eig} function -## for computing eigenvalues. +## For numerical performance, however, the @code{eig} function +## should be used for computing eigenvalues. ## ## If @var{x} is a vector, @code{poly (@var{x})} is a vector of coefficients ## of the polynomial whose roots are the elements of @var{x}. That is, -## of @var{c} is a polynomial, then the elements of +## if @var{c} is a polynomial, then the elements of ## @code{@var{d} = roots (poly (@var{c}))} are contained in @var{c}. -## The vectors @var{c} and @var{d} are, however, not equal due to sorting +## The vectors @var{c} and @var{d} are not identical, however, due to sorting ## and numerical errors. ## @seealso{eig, roots} ## @end deftypefn