sumr

Purpose

Computes the sum of each row of a matrix or the sum of the fastest moving dimension of an L-dimensional array.

Format

y = sumr(x)

Parameters:

x (NxK matrix or L-dimensional array) – data matrix where the last two dimensions are NxK

Returns:

y (Nx1 vector or L-dimensional array) – contains the sum of each row. The last two dimensions are Nx1.

Examples

// Create an additive sequence from 1-12 and reshape it into
// a 3x4 matrix
x = reshape(seqa(1, 1, 12), 3, 4);

// Sum the rows
y = sumr(x);

After the above code, the variables x and y will be:

    1  2  3  4        10
x = 5  6  7  8   y =  26
    9 10 11 12        42

// Reshape an additive sequence from 1-24 into a 2x3x4
// dimensional array
a = areshape(seqa(1, 1, 24), 2|3|4);
z = sumr(a);

a is a 2x3x4 array such that:

Plane [1,.,.]

      1.0000000     2.0000000     3.0000000     4.0000000
      5.0000000     6.0000000     7.0000000     8.0000000
      9.0000000     10.000000     11.000000     12.000000

Plane [2,.,.]

      13.000000     14.000000     15.000000     16.000000
      17.000000     18.000000     19.000000     20.000000
      21.000000     22.000000     23.000000     24.000000

The variable z is equal to:

Plane [1,.,.]

      10.000000
      26.000000
      42.000000

Plane [2,.,.]

      58.000000
      74.000000
      90.000000

See also

Functions sumc()