在Python中生成勒让德多项式的伪范德蒙德矩阵和x, y浮点数组点
要生成勒让德多项式的伪范德蒙德矩阵,可以使用Python NumPy中的`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阶数。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。根据是否存在复数元素,dtype将转换为float64或complex128。标量将转换为一维数组。参数deg是最大阶数列表,形式为[x_deg, y_deg]。
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()方法创建形状相同的点坐标数组:
x = np.array([0.1, 1.4]) y = np.array([1.7, 2.8])
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,可以使用Python NumPy中的`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([0.1, 1.4]) y = np.array([1.7, 2.8]) # 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... [0.1 1.4] Array2... [1.7 2.8] Array1 datatype... float64 Array2 datatype... float64 Dimensions of Array1... 1 Dimensions of Array2... 1 Shape of Array1... (2,) Shape of Array2... (2,) Result... [[ 1.0000000e+00 1.7000000e+00 3.8350000e+00 9.7325000e+00 1.0000000e-01 1.7000000e-01 3.8350000e-01 9.7325000e-01 -4.8500000e-01 -8.2450000e-01 -1.8599750e+00 -4.7202625e+00] [ 1.0000000e+00 2.8000000e+00 1.1260000e+01 5.0680000e+01 1.4000000e+00 3.9200000e+00 1.5764000e+01 7.0952000e+01 2.4400000e+00 6.8320000e+00 2.7474400e+01 1.2365920e+02]]
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