www.gusucode.com > datafun 工具箱matlab源码程序 > datafun/sum.m
%SUM Sum of elements. % S = SUM(X) is the sum of the elements of the vector X. If X is a matrix, % S is a row vector with the sum over each column. For N-D arrays, % SUM(X) operates along the first non-singleton dimension. % % S = SUM(X,DIM) sums along the dimension DIM. % % S = SUM(...,TYPE) specifies the type in which the % sum is performed, and the type of S. Available options are: % % 'double' - S has class double for any input X % 'native' - S has the same class as X % 'default' - If X is floating point, that is double or single, % S has the same class as X. If X is not floating point, % S has class double. % % S = SUM(...,NANFLAG) specifies how NaN (Not-A-Number) values are % treated. The default is 'includenan': % % 'includenan' - the sum of a vector containing NaN values is also NaN. % 'omitnan' - the sum of a vector containing NaN values % is the sum of all its non-NaN elements. If all % elements are NaN, the result is 0. % % Examples: % X = [0 1 2; 3 4 5] % sum(X, 1) % sum(X, 2) % % X = int8(1:20) % sum(X) % returns double(210), accumulates in double % sum(X,'native') % returns int8(127), because it accumulates in % % int8 but overflows and saturates. % % See also PROD, CUMSUM, DIFF, ACCUMARRAY, ISFLOAT. % Copyright 1984-2015 The MathWorks, Inc. % Built-in function.