Mercurial > octave
view scripts/statistics/meansq.m @ 31206:7ae0a0772e9d
maint: merge stable to default
author | Arun Giridhar <arungiridhar@gmail.com> |
---|---|
date | Sun, 28 Aug 2022 12:21:36 -0400 |
parents | 5d3faba0342e |
children | 597f3ee61a48 |
line wrap: on
line source
######################################################################## ## ## Copyright (C) 1995-2022 The Octave Project Developers ## ## See the file COPYRIGHT.md in the top-level directory of this ## distribution or <https://octave.org/copyright/>. ## ## This file is part of Octave. ## ## Octave is free software: you can redistribute it and/or modify it ## under the terms of the GNU General Public License as published by ## the Free Software Foundation, either version 3 of the License, or ## (at your option) any later version. ## ## Octave is distributed in the hope that it will be useful, but ## WITHOUT ANY WARRANTY; without even the implied warranty of ## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the ## GNU General Public License for more details. ## ## You should have received a copy of the GNU General Public License ## along with Octave; see the file COPYING. If not, see ## <https://www.gnu.org/licenses/>. ## ######################################################################## ## -*- texinfo -*- ## @deftypefn {} {@var{y} =} meansq (@var{x}) ## @deftypefnx {} {@var{y} =} meansq (@var{x}, @var{dim}) ## Compute the mean square of the elements of the vector @var{x}. ## ## The mean square is defined as ## @tex ## $$ ## {\rm meansq} (x) = {\sum_{i=1}^N {x_i}^2 \over N} ## $$ ## where $N$ is the number of elements of @var{x}. ## ## @end tex ## @ifnottex ## ## @example ## @group ## meansq (@var{x}) = 1/N SUM_i @var{x}(i)^2 ## @end group ## @end example ## ## @noindent ## where @math{N} is the length of the @var{x} vector. ## ## @end ifnottex ## If @var{x} is a matrix, return a row vector containing the mean square ## of each column. ## ## If the optional argument @var{dim} is given, operate along this dimension. ## @seealso{var, std, moment} ## @end deftypefn function y = meansq (x, dim) if (nargin < 1) print_usage (); endif if (! (isnumeric (x) || islogical (x))) error ("mean: X must be a numeric vector or matrix"); endif nd = ndims (x); sz = size (x); if (nargin < 2) ## Find the first non-singleton dimension. (dim = find (sz > 1, 1)) || (dim = 1); else if (! (isscalar (dim) && dim == fix (dim) && dim > 0)) error ("mean: DIM must be an integer and a valid dimension"); endif endif y = sumsq (x, dim) / size (x, dim); endfunction %!assert (meansq (1:5), 11) %!assert (meansq (single (1:5)), single (11)) %!assert (meansq (magic (4)), [94.5, 92.5, 92.5, 94.5]) %!assert (meansq (magic (4), 2), [109.5; 77.5; 77.5; 109.5]) %!assert (meansq ([1 2], 3), [1 4]) ## Test input validation %!error <Invalid call> meansq () %!error <X must be a numeric> meansq (['A'; 'B']) %!error <DIM must be an integer> meansq (1, ones (2,2)) %!error <DIM must be an integer> meansq (1, 1.5) %!error <DIM must be .* a valid dimension> meansq (1, 0)