Lin Ma - 4 months ago 120

Python Question

Using Python 2.7 with miniconda interpreter. I am confused by what means N-D coordinate in the following statements, and could anyone tell how in the below sample

`xv`

`yv`

"Make N-D coordinate arrays for vectorized evaluations of N-D scalar/vector fields over N-D grids, given one-dimensional coordinate arrays x1, x2,..., xn."

http://docs.scipy.org/doc/numpy/reference/generated/numpy.meshgrid.html

`>>> nx, ny = (3, 2)`

>>> x = np.linspace(0, 1, nx)

>>> y = np.linspace(0, 1, ny)

>>> xv, yv = meshgrid(x, y)

>>> xv

array([[ 0. , 0.5, 1. ],

[ 0. , 0.5, 1. ]])

>>> yv

array([[ 0., 0., 0.],

[ 1., 1., 1.]])

regards,

Lin

Answer

`xv,yv`

are simply defined as:

```
xv = np.array([x for _ in y])
yv = np.array([y for _ in x]).T
```

so that for every index pair `(i,j)`

, you have

```
xv[i,j] = x[i]
yv[i,j] = y[j]
```

which is useful especially for plotting 2D maps.