Mercurial > octave-antonio
view scripts/special-matrix/magic.m @ 20162:2645f9ef8c88 stable
doc: Update more docstrings to have one sentence summary as first line.
Reviewed specfun, special-matrix, testfun, and time script directories.
* scripts/specfun/expint.m, scripts/specfun/isprime.m,
scripts/specfun/legendre.m, scripts/specfun/primes.m,
scripts/specfun/reallog.m, scripts/specfun/realsqrt.m,
scripts/special-matrix/gallery.m, scripts/special-matrix/hadamard.m,
scripts/special-matrix/hankel.m, scripts/special-matrix/hilb.m,
scripts/special-matrix/invhilb.m, scripts/special-matrix/magic.m,
scripts/special-matrix/pascal.m, scripts/special-matrix/rosser.m,
scripts/special-matrix/toeplitz.m, scripts/special-matrix/vander.m,
scripts/special-matrix/wilkinson.m, scripts/testfun/assert.m,
scripts/testfun/demo.m, scripts/testfun/example.m, scripts/testfun/fail.m,
scripts/testfun/rundemos.m, scripts/testfun/runtests.m,
scripts/testfun/speed.m, scripts/time/asctime.m, scripts/time/calendar.m,
scripts/time/clock.m, scripts/time/ctime.m, scripts/time/datenum.m,
scripts/time/datestr.m, scripts/time/datevec.m, scripts/time/etime.m,
scripts/time/is_leap_year.m, scripts/time/now.m, scripts/time/weekday.m:
Update more docstrings to have one sentence summary as first line.
author | Rik <rik@octave.org> |
---|---|
date | Sun, 03 May 2015 17:00:11 -0700 |
parents | 9fc020886ae9 |
children |
line wrap: on
line source
## Copyright (C) 1999-2015 Paul Kienzle ## ## 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 ## <http://www.gnu.org/licenses/>. ## -*- texinfo -*- ## @deftypefn {Function File} {} magic (@var{n}) ## ## Create an @var{n}-by-@var{n} magic square. ## ## A magic square is an arrangement of the integers @code{1:n^2} such that the ## row sums, column sums, and diagonal sums are all equal to the same value. ## ## Note: @var{n} must be greater than 2 for the magic square to exist. ## @end deftypefn function A = magic (n) if (nargin != 1) print_usage (); endif if (n != fix (n) || n < 0 || n == 2) error ("magic: N must be a positive integer not equal to 2"); endif if (n == 0) A = []; elseif (mod (n, 2) == 1) shift = floor ((0:n*n-1)/n); c = mod ([1:n*n] - shift + (n-3)/2, n); r = mod ([n*n:-1:1] + 2*shift, n); A(c*n+r+1) = 1:n*n; A = reshape (A, n, n); elseif (mod (n, 4) == 0) A = reshape (1:n*n, n, n)'; I = [1:4:n, 4:4:n]; J = fliplr (I); A(I,I) = A(J,J); I = [2:4:n, 3:4:n]; J = fliplr (I); A(I,I) = A(J,J); elseif (mod (n, 4) == 2) m = n/2; A = magic (m); A = [A, A+2*m*m; A+3*m*m, A+m*m]; k = (m-1)/2; if (k > 1) I = 1:m; J = [2:k, n-k+2:n]; A([I,I+m],J) = A([I+m,I],J); endif I = [1:k, k+2:m]; A([I,I+m],1) = A([I+m,I],1); I = k + 1; A([I,I+m],I) = A([I+m,I],I); endif endfunction %!test %! for i = 3:30 %! A = magic (i); %! assert (norm(diff([sum(diag(A)),sum(diag(flipud(A))),sum(A),sum(A')])),0); %! endfor %!assert (isempty (magic (0))) %!assert (magic (1), 1) ## Test input validation %!error magic () %!error magic (1, 2) %!error <N must be a positive integer not equal to 2> magic (1.5) %!error <N must be a positive integer not equal to 2> magic (-1) %!error <N must be a positive integer not equal to 2> magic (2)