Sum of many inputs

 Hi guys,

I want to implement a function that I find the sum of as many input arguments I give.

For example in one case it can be (a+b). In another (a+b+c+d...) or (a+b+c).

I try to use varargin but don't know how.. Any suggestions?

thanx d.

Answer 1

[Matt Fig]

function S = sumthemall(varargin)
% Takes as many scalars as you want, returns the sum.
S = sum([varargin{:}]);

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EDIT O.k., since Walter wants to generalize it, I will generalize it further ;).

function S = sumthemall(varargin)
% Takes as many numeric arrays as you want, returns the sum.
S = 0;
for ii = 1:nargin
   S = S+sum(varargin{ii}(:));
end

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Now from the command line:

sumthemall(1,2,3,[4,5,6,7,8,9],magic(3),round(rand(3,4,5,6)*8))
ans =
        1532

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EDIT2

Here is a better (maybe?) generalization.

function S = sumthemall(varargin)
% Takes as many numeric arrays as you can dish and performs a sum.
% If all inputs are the same size (except for possible scalars), then the
% output will be that same size.  If not, the result is a scalar sum of all
% elements of all arguments.

S = 0;
Sz = cellfun(@size,varargin,'Un',0);
sclrs = cellfun(@(x) isequal(x,[1 1]),Sz);
Nscl = Sz(~sclrs);

if all(cellfun(@(x) isequal(x,Nscl{1}),Nscl))
    for ii = 1:nargin
       S = S + varargin{ii};
    end
else
    for ii = 1:nargin
       S = S + sum(varargin{ii}(:));
    end
end

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Now from the command line:

>> sumthemall(1,2,3,7,magic(3),round(rand(3)*80))
ans =
    38    87    76
    79    63    42
    27    24    88
>> sumthemall(1,2,3,7,magic(3),round(rand(3)*80),[5 6])
ans =
   430

[Walter Roberson]

You can do better than that, Matt :)

function S = sumthemall(varargin)

S = cellfun(@(x) x(:), varargin, 'Uniform', 0);

S = sum(vertcat(S{:}));

end

[Matt Fig]

Funny, too many CELLFUN calls already!

Answer 2

[Walter Roberson]

function S = sumthemall(varargin)
  % Takes as many scalars, equal-length vectors, or
  % equal-size arrays as you want, returns the sum.
  if ~nargin
    S = 0;
  else
    d = 1 + ndims(varargin{1});
    S = sum( cat(d, varargin{:}), d );
  end
end