Directional gradient along the *x*-axis, returned
as non-sparse matrix equal in size to image `I`

.
The *x*-axis points in the direction of increasing
column subscripts. The output matrices are of class `double`

,
unless the input image is of class `single`

, in which
case they are of class `single`

.

When the input image `I`

is a gpuArray, `Gx`

is
a gpuArray.

**Data Types: **`single`

| `double`

Directional gradient along the *x*-axis, returned
as non-sparse gpuArray equal in size to image `I`

.
The *x*-axis points in the direction of increasing
column subscripts. The output matrices are of class `double`

,
unless the input image is of class `single`

, in which
case they are of class `single`

.

**Data Types: **`single`

| `double`

Directional gradients along the *y*-axis, returned
as non-sparse matrix equal in size to image `I`

.
The *y*-axis points in the direction of increasing
row subscripts. The output matrices are of class `double`

,
unless the input image is of class `single`

, in which
case they are of class `single`

.

**Data Types: **`single`

| `double`

Directional gradients along the *y*-axis, returned
as non-sparse gpuArray equal in size to image `I`

.
The *y*-axis points in the direction of increasing
row subscripts. The output matrices are of class `double`

,
unless the input image is of class `single`

, in which
case they are of class `single`

.

**Data Types: **`single`

| `double`