Divides two numerical arrays (elementwise). There are two forms for its use, both with the same general syntax:
y = a ./ b
where a
and b
are n
-dimensional arrays of numerical type. In the
first case, the two arguments are the same size, in which case, the
output y
is the same size as the inputs, and is the element-wise
division of b
by a
. In the second case, either a
or b
is a scalar,
in which case y
is the same size as the larger argument,
and is the division of the scalar with each element of the other argument.
The type of y
depends on the types of a
and b
using type
promotion rules, with one important exception: unlike C
, integer
types are promoted to double
prior to division.
There are three formulae for the dot-right-divide operator, depending on the sizes of the three arguments. In the most general case, in which the two arguments are the same size, the output is computed via:
If
a
is a scalar, then the output is computed via
On the other hand, if
b
is a scalar, then the output is computed via
Here are some examples of using the dot-right-divide operator. First, a
straight-forward usage of the ./
operator. The first example
is straightforward:
--> 3 ./ 8 ans = <double> - size: [1 1] 0.375000000000000
Note that this is not the same as evaluating 3/8
in C
- there,
the output would be 0
, the result of the integer division.
We can also divide complex arguments:
--> a = 3 + 4*i a = <complex> - size: [1 1] 3.0000000 4.0000000 i --> b = 5 + 8*i b = <complex> - size: [1 1] 5.0000000 8.0000000 i --> c = a ./ b c = <complex> - size: [1 1] 0.52808988 -0.044943821 i
If a complex
value is divided by a double
, the result is
promoted to dcomplex
.
--> b = a ./ 2.0 b = <dcomplex> - size: [1 1] 1.500000000000000 2.000000000000000 i
We can also demonstrate the three forms of the dot-right-divide operator. First the element-wise version:
--> a = [1,2;3,4] a = <int32> - size: [2 2] Columns 1 to 2 1 2 3 4 --> b = [2,3;6,7] b = <int32> - size: [2 2] Columns 1 to 2 2 3 6 7 --> c = a ./ b c = <double> - size: [2 2] Columns 1 to 2 0.500000000000000 0.666666666666667 0.500000000000000 0.571428571428571
Then the scalar versions
--> c = a ./ 3 c = <double> - size: [2 2] Columns 1 to 2 0.333333333333333 0.666666666666667 1.000000000000000 1.333333333333333 --> c = 3 ./ a c = <double> - size: [2 2] Columns 1 to 2 3.000000000000000 1.500000000000000 1.000000000000000 0.750000000000000