Numpy的meshgrid对于将两个向量转换为坐标网格非常有用。将其扩展到三个维度的最简单方法是什么?因此,给定三个向量x,y和z,构造可以用作坐标的3x3D数组(而不是2x2D数组)。
这是meshgrid的源代码:
def meshgrid(x,y): """ Return coordinate matrices from two coordinate vectors. Parameters ---------- x, y : ndarray Two 1-D arrays representing the x and y coordinates of a grid. Returns ------- X, Y : ndarray For vectors `x`, `y` with lengths ``Nx=len(x)`` and ``Ny=len(y)``, return `X`, `Y` where `X` and `Y` are ``(Ny, Nx)`` shaped arrays with the elements of `x` and y repeated to fill the matrix along the first dimension for `x`, the second for `y`. See Also -------- index_tricks.mgrid : Construct a multi-dimensional "meshgrid" using indexing notation. index_tricks.ogrid : Construct an open multi-dimensional "meshgrid" using indexing notation. Examples -------- >>> X, Y = np.meshgrid([1,2,3], [4,5,6,7]) >>> X array([[1, 2, 3], [1, 2, 3], [1, 2, 3], [1, 2, 3]]) >>> Y array([[4, 4, 4], [5, 5, 5], [6, 6, 6], [7, 7, 7]]) `meshgrid` is very useful to evaluate functions on a grid. >>> x = np.arange(-5, 5, 0.1) >>> y = np.arange(-5, 5, 0.1) >>> xx, yy = np.meshgrid(x, y) >>> z = np.sin(xx**2+yy**2)/(xx**2+yy**2) """ x = asarray(x) y = asarray(y) numRows, numCols = len(y), len(x) # yes, reversed x = x.reshape(1,numCols) X = x.repeat(numRows, axis=0) y = y.reshape(numRows,1) Y = y.repeat(numCols, axis=1) return X, Y
这很容易理解。我将模式扩展到任意数量的维度,但是此代码绝不是经过优化的(也没有经过彻底的错误检查),但是您可以付钱。希望能帮助到你:
def meshgrid2(*arrs): arrs = tuple(reversed(arrs)) #edit lens = map(len, arrs) dim = len(arrs) sz = 1 for s in lens: sz*=s ans = [] for i, arr in enumerate(arrs): slc = [1]*dim slc[i] = lens[i] arr2 = asarray(arr).reshape(slc) for j, sz in enumerate(lens): if j!=i: arr2 = arr2.repeat(sz, axis=j) ans.append(arr2) return tuple(ans)