Mercurial > octave-libtiff
changeset 23896:fe1763af4021
humps.m: Overhaul function.
* humps.m: Use a single line summary of function as first docstring line.
Add @seealso references. Use same variable names in function prototype
as in documentation.
| author | Rik <rik@octave.org> |
|---|---|
| date | Fri, 11 Aug 2017 18:31:04 -0700 |
| parents | d37e8e9decce |
| children | c3cfd3115b78 |
| files | scripts/optimization/humps.m |
| diffstat | 1 files changed, 20 insertions(+), 21 deletions(-) [+] |
line wrap: on
line diff
--- a/scripts/optimization/humps.m Fri Aug 11 18:09:51 2017 -0700 +++ b/scripts/optimization/humps.m Fri Aug 11 18:31:04 2017 -0700 @@ -19,9 +19,11 @@ ## Author: Nicholas R. Jankowski <jankowskin@asme.org> ## -*- texinfo -*- -## @deftypefn {} {} humps (@var{x}) +## @deftypefn {} {@var{y} =} humps (@var{x}) ## @deftypefnx {} {[@var{x}, @var{y}] =} humps (@var{x}) -## Return the output of the rational function: +## Evaluate a function with multiple minima, maxima, and zero crossings. +## +## The output @var{y} is the evaluation of the rational function: ## ## @tex ## $$y = -{ {1200x^4 - 2880x^3 + 2036x^2 - 340x - 88} \over {200x^4 - 480x^3 + 406x^2 - 138x - 17} }$$ @@ -38,46 +40,43 @@ ## ## @end ifnottex ## -## @var{x} may be a scalar, vector or array. @code{humps} is vectorized such -## that @var{yi} = humps (@var{xi}) +## @var{x} may be a scalar, vector or array. If @var{x} is omitted, the +## default range [0:0.05:1] is used. ## -## If @var{x} is omitted, the range [0:0.05:1] is used instead. -## -## When called with two output arguments, [@var{x},@var{y}], @var{x} will -## contain the input value(s), and @var{y} will contain the output from +## When called with two output arguments, [@var{x}, @var{y}], @var{x} will +## contain the input values, and @var{y} will contain the output from ## @code{humps}. ## -## @code{humps} has two local maxima located near @var{x} = 0.300 and 0.893, -## a local minimum near @var{x} = 0.637, and zeros near @var{x} = -0.132 and -## 1.300. @code{humps} is a useful function for testing algorithms to find -## zeros or local minima and maxima. +## Programming Notes: @code{humps} has two local maxima located near @var{x} = +## 0.300 and 0.893, a local minimum near @var{x} = 0.637, and zeros near +## @var{x} = -0.132 and 1.300. @code{humps} is a useful function for testing +## algorithms which find zeros or local minima and maxima. ## ## Try @code{demo humps} to see a plot of the @code{humps} function. +## @seealso{fzero, fminbnd, fminunc, fminsearch} ## @end deftypefn -function varargout = humps (x = [0:0.05:1]) +function [x, y] = humps (x = [0:0.05:1]) if (nargin > 1) print_usage (); endif - y = - 4*( 300*x.^4 - 720*x.^3 + 509*x.^2 - 87*x - 22) ./ ... - ((10*x.^2 - 6*x + 1).*(20*x.^2 - 36*x + 17)); + y = - 4*( 300*x.^4 - 720*x.^3 + 509*x.^2 - 87*x - 22) ./ ... + ((10*x.^2 - 6*x + 1).*(20*x.^2 - 36*x + 17)); - if (nargout > 1) - varargout = {x, y}; - else - varargout = {y}; + if (nargout <= 1) + x = y; endif endfunction + %!demo %! clf; %! fplot (@humps, [0, 2]); %! title ("humps() function"); -## tests ## value checks %!assert (humps (0), 88/17, 10*eps) %!assert (humps (1), 16, 10*eps) @@ -100,5 +99,5 @@ %!assert (humps (NaN), NaN) %!assert (humps ([]), []) -## errors +## Test input validation %!error humps (1,3)