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comparison scripts/general/accumarray.m @ 13787:8bb7bdbe9c69

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Clarify max/min in accumarray and uniformise its behaviour
author Jordi Gutiérrez Hermoso <jordigh@octave.org>
date Wed, 02 Nov 2011 00:25:27 -0400
parents 8aaaef4a69aa
children 9ab64f063c96
comparison
equal deleted inserted replaced
13786:40dab5d70115 13787:8bb7bdbe9c69
38 ## @var{func} function. This should be a function or function handle 38 ## @var{func} function. This should be a function or function handle
39 ## that accepts a column vector and returns a scalar. The result of the 39 ## that accepts a column vector and returns a scalar. The result of the
40 ## function should not depend on the order of the subscripts. 40 ## function should not depend on the order of the subscripts.
41 ## 41 ##
42 ## The elements of the returned array that have no subscripts associated 42 ## The elements of the returned array that have no subscripts associated
43 ## with them are set to zero. Defining @var{fillval} to some other 43 ## with them are set to zero. Defining @var{fillval} to some other value
44 ## value allows these values to be defined. 44 ## allows these values to be defined. This behaviour changes, however,
45 ## for certain values of @var{func}. If @var{func} is @code{min}
46 ## (respectively, @code{max}) then the result will be filled with the
47 ## minimum (respectively, maximum) integer if @var{vals} is of integral
48 ## type, logical false (respectively, logical true) if @var{vals} is of
49 ## logical type, zero if @var{fillval} is zero and all values are
50 ## nonpositive (respectively, nonnegative), and NaN otherwise.
45 ## 51 ##
46 ## By default @code{accumarray} returns a full matrix. If 52 ## By default @code{accumarray} returns a full matrix. If
47 ## @var{issparse} is logically true, then a sparse matrix is returned 53 ## @var{issparse} is logically true, then a sparse matrix is returned
48 ## instead. 54 ## instead.
49 ## 55 ##
246 252
247 if (isinteger (vals)) 253 if (isinteger (vals))
248 zero = intmax (class (vals)); 254 zero = intmax (class (vals));
249 elseif (islogical (vals)) 255 elseif (islogical (vals))
250 zero = true; 256 zero = true;
257 elseif (fillval == 0 && all (vals(:) <= 0))
258 ## This is a common case - fillval is zero, all numbers nonpositive.
259 zero = 0;
251 else 260 else
252 zero = NaN; # Neutral value. 261 zero = NaN; # Neutral value.
253 endif 262 endif
254 263
255 if (isempty (sz)) 264 if (isempty (sz))