Name

sum — sum (row sum, column sum) of vector/matrix entries

Calling Sequence

y=sum(x)
y=sum(x,'r') or y=sum(x,1)

y=sum(x,'c') or y=sum(x,2)

y=sum(x,'m')

Parameters

x

vector or matrix (real, complex, sparse or polynomial)

y

scalar or vector

Description

For a vector or a matrix x, y=sum(x) returns in the scalar y the sum of all the entries of x.

y=sum(x,'r') (or, equivalently, y=sum(x,1)) is the rowwise sum: y(j)= sum(x(:,j)). y is a row vector

y=sum(x,'c') (or, equivalently, y=sum(x,2)) is the columnwise sum. It returns in each entry of the column vector y the sum : y(i)= sum(x(i,:)))).

y=sum(x,'m') is the sum along the first non singleton dimension of x (for compatibility with Matlab).

Examples

 
A=[1,2;3,4];
trace(A)-sum(diag(A))
sum(A,'c')-A*ones(2,1)
sum(A+%i)
A=sparse(A);sum(A,'c')-A*ones(2,1)
s=poly(0,'s');
M=[s,%i+s;s^2,1];
sum(M),sum(M,2)

See Also

cumsum, prod