Mercurial > octave-antonio
changeset 19169:1faae07afbd8
Overhaul givens and planerot functions.
* givens.cc (Fgivens): Redo docstring. Remove useless default to detect
nargout > 2 in switch statements.
* planerot.m: Redo docstring. Add input validation. Add BIST tests for input validation.
| author | Rik <rik@octave.org> |
|---|---|
| date | Sat, 27 Sep 2014 13:41:57 -0700 |
| parents | 9163a6e9b096 |
| children | a6d44158bc6d |
| files | libinterp/corefcn/givens.cc scripts/linear-algebra/planerot.m |
| diffstat | 2 files changed, 31 insertions(+), 25 deletions(-) [+] |
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--- a/libinterp/corefcn/givens.cc Sat Sep 27 12:47:37 2014 -0700 +++ b/libinterp/corefcn/givens.cc Sat Sep 27 13:41:57 2014 -0700 @@ -32,10 +32,12 @@ DEFUN (givens, args, nargout, "-*- texinfo -*-\n\ -@deftypefn {Built-in Function} {@var{g} =} givens (@var{x}, @var{y})\n\ +@deftypefn {Built-in Function} {@var{G} =} givens (@var{x}, @var{y})\n\ @deftypefnx {Built-in Function} {[@var{c}, @var{s}] =} givens (@var{x}, @var{y})\n\ +Compute the Givens rotation matrix @var{G}.\n\ +\n\ @tex\n\ -Return a $2\\times 2$ orthogonal matrix\n\ +The Givens matrix is a $2\\times 2$ orthogonal matrix\n\ $$\n\ G = \\left[\\matrix{c & s\\cr -s'& c\\cr}\\right]\n\ $$\n\ @@ -46,11 +48,20 @@ with $x$ and $y$ scalars.\n\ @end tex\n\ @ifnottex\n\ -Return a 2 by 2 orthogonal matrix\n\ -@code{@var{g} = [@var{c} @var{s}; -@var{s}' @var{c}]} such that\n\ -@code{@var{g} [@var{x}; @var{y}] = [*; 0]} with @var{x} and @var{y} scalars.\n\ +The Givens matrix is a 2 by 2 orthogonal matrix\n\ +\n\ +@code{@var{g} = [@var{c} @var{s}; -@var{s}' @var{c}]}\n\ +\n\ +such that\n\ +\n\ +@code{@var{g} [@var{x}; @var{y}] = [*; 0]}\n\ +\n\ +with @var{x} and @var{y} scalars.\n\ @end ifnottex\n\ \n\ +If two output arguments are requested, return the factors @var{c} and\n\ +@var{s} rather than the Givens rotation matrix.\n\ +\n\ For example:\n\ \n\ @example\n\ @@ -60,6 +71,7 @@ -0.70711 0.70711\n\ @end group\n\ @end example\n\ +@seealso{planerot}\n\ @end deftypefn") { octave_value_list retval; @@ -97,10 +109,6 @@ retval(1) = result (0, 1); retval(0) = result (0, 0); break; - - default: - error ("givens: invalid number of output arguments"); - break; } } } @@ -127,10 +135,6 @@ retval(1) = result (0, 1); retval(0) = result (0, 0); break; - - default: - error ("givens: invalid number of output arguments"); - break; } } } @@ -160,10 +164,6 @@ retval(1) = result (0, 1); retval(0) = result (0, 0); break; - - default: - error ("givens: invalid number of output arguments"); - break; } } } @@ -190,10 +190,6 @@ retval(1) = result (0, 1); retval(0) = result (0, 0); break; - - default: - error ("givens: invalid number of output arguments"); - break; } } } @@ -211,4 +207,5 @@ %!error givens () %!error givens (1) +%!error [a,b,c] = givens (1, 1) */
--- a/scripts/linear-algebra/planerot.m Sat Sep 27 12:47:37 2014 -0700 +++ b/scripts/linear-algebra/planerot.m Sat Sep 27 13:41:57 2014 -0700 @@ -17,8 +17,8 @@ ## <http://www.gnu.org/licenses/>. ## -*- texinfo -*- -## @deftypefn {Function File} {[@var{g}, @var{y}] =} planerot (@var{x}) -## Given a two-element column vector, returns the +## @deftypefn {Function File} {[@var{G}, @var{y}] =} planerot (@var{x}) +## Given a two-element column vector, return the ## @tex ## $2 \times 2$ orthogonal matrix ## @end tex @@ -31,8 +31,16 @@ ## @end deftypefn function [G, y] = planerot (x) + + if (nargin != 1) + print_usage (); + elseif (! (isvector (x) && numel (x) == 2)) + error ("planerot: X must be a 2-element vector"); + endif + G = givens (x(1), x(2)); y = G * x(:); + endfunction @@ -42,7 +50,8 @@ %! assert (g, [x(1) x(2); -x(2) x(1)] / sqrt (x(1)^2 + x(2)^2), 2e-8); %! assert (y(2), 0, 2e-8); -%!error planerot ([0]) -%!error planerot ([0 0 0]) %!error planerot () +%!error planerot (1,2) +%!error <X must be a 2-element vector> planerot (ones (2,2)) +%!error <X must be a 2-element vector> planerot ([0 0 0])