在 Python 中生成勒让德多项式和 x、y 复数点数组的伪范德蒙德矩阵
要生成勒让德多项式的伪范德蒙德矩阵,请在 Python Numpy 中使用 legendre.legvander2d() 方法。该方法返回伪范德蒙德矩阵。返回矩阵的形状为 x.shape + (deg + 1,),其中最后一个索引是相应勒让德多项式的次数。dtype 将与转换后的 x 相同。
参数 x、y 是点坐标数组,所有数组都具有相同的形状。dtype 将根据任何元素是否为复数转换为 float64 或 complex128。标量将转换为一维数组。参数 deg 是 [x_deg, y_deg] 形式的最大次数列表。
步骤
首先,导入所需的库:
import numpy as np from numpy.polynomial import legendre as L
使用 numpy.array() 方法创建具有相同形状的点坐标数组:
x = np.array([-2.+2.j, -1.+2.j]) y = np.array([1.+2.j, 2.+2.j])
显示数组:
print("Array1...\n",x) print("\nArray2...\n",y)
显示数据类型:
print("\nArray1 datatype...\n",x.dtype) print("\nArray2 datatype...\n",y.dtype)
检查两个数组的维度:
print("\nDimensions of Array1...\n",x.ndim) print("\nDimensions of Array2...\n",y.ndim)
检查两个数组的形状:
print("\nShape of Array1...\n",x.shape) print("\nShape of Array2...\n",y.shape)
要生成勒让德多项式的伪范德蒙德矩阵,请在 Python Numpy 中使用 legendre.legvander2d() 方法:
x_deg, y_deg = 2, 3 print("\nResult...\n",L.legvander2d(x,y, [x_deg, y_deg]))
示例
import numpy as np from numpy.polynomial import legendre as L # Create arrays of point coordinates, all of the same shape using the numpy.array() method x = np.array([-2.+2.j, -1.+2.j]) y = np.array([1.+2.j, 2.+2.j]) # Display the arrays print("Array1...\n",x) print("\nArray2...\n",y) # Display the datatype print("\nArray1 datatype...\n",x.dtype) print("\nArray2 datatype...\n",y.dtype) # Check the Dimensions of both the arrays print("\nDimensions of Array1...\n",x.ndim) print("\nDimensions of Array2...\n",y.ndim) # Check the Shape of both the arrays print("\nShape of Array1...\n",x.shape) print("\nShape of Array2...\n",y.shape) # To generate a pseudo Vandermonde matrix of the Legendre polynomial, use the legendre.legvander2d() method in Python Numpy x_deg, y_deg = 2, 3 print("\nResult...\n",L.legvander2d(x,y, [x_deg, y_deg]))
输出
Array1... [-2.+2.j -1.+2.j] Array2... [1.+2.j 2.+2.j] Array1 datatype... complex128 Array2 datatype... complex128 Dimensions of Array1... 1 Dimensions of Array2... 1 Shape of Array1... (2,) Shape of Array2... (2,) Result... [[ 1. +0.j 1. +2.j -5. +6.j -29. -8.j -2. +2.j -6. -2.j -2. -22.j 74. -42.j -0.5 -12.j 23.5 -13.j 74.5 +57.j -81.5 +352.j] [ 1. +0.j 2. +2.j -0.5 +12.j -43. +37.j -1. +2.j -6. +2.j -23.5 -13.j -31. -123.j -5. -6.j 2. -22.j 74.5 -57.j 437. +73.j]]
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