sumc#
Purpose#
Computes the sum of each column of a matrix or the sum across the second-fastest moving dimension of an L-dimensional array.
Format#
- y = sumc(x)#
- Parameters:
x (matrix or array) – NxK matrix or L-dimensional array where the last two dimensions are \(NxK\)
- Returns:
y (Kx1 vector or L-dimensional array) – contains the sum of each column, where the last two dimensions are \(Kx1\).
Examples#
// Create a 12x1 vector containing an additive sequence
// counting by twos, from 0-22, i.e. 2, 4, 6, 8...22
x = seqa(0, 2, 12);
// Reshape the 12x1 vector 'x' into a 3x4 matrix
x = reshape(x, 3, 4);
// Sum the columns
y = sumc(x);
After the above code, the variables x and y are equal to:
0 2 4 6
x = 8 10 12 14
16 18 20 22
24
y = 30
36
42
// Create an additive sequence from 1-24 and reshape it into
// a 2x3x4 array
a = areshape(seqa(1, 1, 24), 2|3|4);
// Sum the columns across the second fastest moving
// dimension
z = sumc(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
Variable z is a 2x4x1 array equal to:
Plane [1,.,.]
15.000000
18.000000
21.000000
24.000000
Plane [2,.,.]
51.000000
54.000000
57.000000
60.000000