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From: Ashok1288 kumar on 26 Jul 2010 08:43
when I use sum() function to obtain the sum of columns of a matrix I am getting an error!

Here is my commands
"
>> a={1,2,3;4,5,6;7,8,9}

a =

[1] [2] [3]
[4] [5] [6]
[7] [8] [9]

>> sum(a);
??? Undefined function or method 'sum' for input arguments of type 'cell'.
"

Will you please help me with this since i am a newbie to Matlab.

Thanks in advance.
From: us on 26 Jul 2010 08:49
"Ashok1288 kumar" <asok1288(a)gmail.com> wrote in message <i2jvso$2br$1(a)fred.mathworks.com>...
> when I use sum() function to obtain the sum of columns of a matrix I am getting an error!
>
> Here is my commands
> "
> >> a={1,2,3;4,5,6;7,8,9}
>
> a =
>
> [1] [2] [3]
> [4] [5] [6]
> [7] [8] [9]
>
> >> sum(a);
> ??? Undefined function or method 'sum' for input arguments of type 'cell'.
> "
>
> Will you please help me with this since i am a newbie to Matlab.
>
> Thanks in advance.

one of the solutions

a={1,2,3;4,5,6;7,8,9}
r=sum(cell2mat(a))
% r = 12 15 18

us
From: Dev on 26 Jul 2010 08:55
do this :
a=[1,2,3;4,5,6;7,8,9]

sum works on array of type double.



"Ashok1288 kumar" <asok1288(a)gmail.com> wrote in message <i2jvso$2br$1(a)fred.mathworks.com>...
> when I use sum() function to obtain the sum of columns of a matrix I am getting an error!
>
> Here is my commands
> "
> >> a={1,2,3;4,5,6;7,8,9}
>
> a =
>
> [1] [2] [3]
> [4] [5] [6]
> [7] [8] [9]
>
> >> sum(a);
> ??? Undefined function or method 'sum' for input arguments of type 'cell'.
> "
>
> Will you please help me with this since i am a newbie to Matlab.
>
> Thanks in advance.
From: Ashok1288 kumar on 26 Jul 2010 09:06
thanks what is the difference in using [] and {} in fact both denote array?

Thanks
From: Steven_Lord on 26 Jul 2010 09:10


"Ashok1288 kumar" <asok1288(a)gmail.com> wrote in message
news:i2k17t$di$1(a)fred.mathworks.com...
> thanks what is the difference in using [] and {} in fact both denote
> array?

An array constructed using [] is a numeric array (by default, a double
array.)

http://www.mathworks.com/access/helpdesk/help/techdoc/learn_matlab/f2-12841.html

http://www.mathworks.com/access/helpdesk/help/techdoc/matlab_prog/f2-12135.html

Each element in a numeric array must be the same data type as the other
elements in the array, and each element is a scalar (one number only.)

An array constructed using {} is a cell array.

http://www.mathworks.com/access/helpdesk/help/techdoc/learn_matlab/f4-2137.html#f4-2245

http://www.mathworks.com/access/helpdesk/help/techdoc/matlab_prog/br04bw6-98.html

Each cell in a cell array can contain a numeric array of a different size,
and each one can be of a different data type. [The _cells_ that make up the
cell array are all scalar and are all cell arrays; the _contents_ of the
cells may differ in size and type.]

--
Steve Lord
slord(a)mathworks.com
comp.soft-sys.matlab (CSSM) FAQ: http://matlabwiki.mathworks.com/MATLAB_FAQ
To contact Technical Support use the Contact Us link on
http://www.mathworks.com

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