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sum | Examples See Also |
B = sum(A)
B = sum(A,
dim)
B = sum(A)
returns sums along different dimensions of an array.
If A
is a vector, sum(A)
returns the sum of the elements.
If A
is a matrix, sum(A)
treats the columns of A
as vectors, returning a row vector of the sums of each column.
If A
is a multidimensional array, sum(A)
treats the values along the first non-singleton dimension as vectors, returning an array of row vectors.
B = sum(A,dim)
sums along the dimension of A
specified by scalar dim
.
sum(diag(X))
is the trace
of X
.
The magic square of order 3 is
M = magic(3) M = 8 1 6 3 5 7 4 9 2This is called a magic square because the sums of the elements in each column are the same.
sum(M) = 15 15 15as are the sums of the elements in each row, obtained by transposing:
sum(M') = 15 15 15
cumsum
Cumulative sum
diff
Differences and approximate derivatives
prod
Product of array elements
trace
Sum of diagonal elements