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## -*- texinfo -*-
## @deftypefn  {} {@var{l} =} lcm (@var{x}, @var{y})
## @deftypefnx {} {@var{l} =} lcm (@var{x}, @var{y}, @dots{})
## Compute the least common multiple of @var{x} and @var{y}, or of the list of
## all arguments.
##
## All inputs must be of the same size, or scalar.  All elements must be
## real integer or Gaussian (complex) integer.  For complex inputs, the result
## is unique only up to a phase factor (multiplication by +1, +i, -1, or -i),
## and one of the four is returned arbitrarily.
##
## Example code:
##
## @example
## @group
## lcm (5:8, 9:12)
##    @xresult{}  45  30  77  24
## @end group
## @end example
##
## Programming tip: To find the LCM of all the elements of a single array, use
## @code{num2cell} instead of nested calls or a loop:
##
## @example
## @group
## x = 1:10;    # vector or array of inputs
## lcm (num2cell (x) @{:@})
##    @xresult{}     2520
## @end group
## @end example
## @seealso{factor, gcd, isprime}
## @end deftypefn

function l = lcm (varargin)

  if (nargin < 2)
    print_usage ();
  endif

  if (common_size (varargin{:}) != 0)
    error ("lcm: all args must be the same size or scalar");
  elseif (! all (cellfun ("isnumeric", varargin)))
    error ("lcm: all arguments must be numeric");
  endif

  l = varargin{1};
  for i = 2:nargin
    x = varargin{i};
    msk = (l == 0 & x == 0);
    l .*= x ./ gcd (l, x);
    l(msk) = 0;
  endfor

  if (isfloat (l) && l > flintmax (l))
    warning ("Octave:lcm:large-output-float", ...
             "lcm: possible loss of precision");
  elseif (isinteger (l) && l == intmax (l))
    warning ("Octave:lcm:large-output-integer", ...
             "lcm: result may have saturated at intmax");
  endif

endfunction


%!assert (lcm (3, 5, 7, 15), 105)

## Test input validation
%!error <Invalid call> lcm ()
%!error <Invalid call> lcm (1)
%!error <same size or scalar> lcm ([1 2], [1 2 3])
%!error <arguments must be numeric> lcm ([1 2], {1 2})
%!warning <loss of precision>   lcm (num2cell (double (1:47)){:});
%!warning <loss of precision>   lcm (num2cell (single (1:47)){:});
%!warning <result .* saturated> lcm (num2cell (uint64 (1:47)){:});
%!warning <result .* saturated> lcm (num2cell (uint32 (1:47)){:});
%!warning <result .* saturated> lcm (num2cell (uint16 (1:47)){:});
%!warning <result .* saturated> lcm (num2cell ( uint8 (1:47)){:});
%!warning <result .* saturated> lcm (num2cell ( int64 (1:47)){:});
%!warning <result .* saturated> lcm (num2cell ( int32 (1:47)){:});
%!warning <result .* saturated> lcm (num2cell ( int16 (1:47)){:});
%!warning <result .* saturated> lcm (num2cell (  int8 (1:47)){:});
