在 Python 中使用复数点数组生成切比雪夫多项式的范德蒙矩阵
要生成切比雪夫多项式的范德蒙矩阵,请在 Python Numpy 中使用 chebyshev.chebvander()。该方法返回范德蒙矩阵。返回矩阵的形状为 x.shape + (deg + 1,),其中最后一个索引是相应切比雪夫多项式的次数。dtype 将与转换后的 x 相同。
参数 a 是点数组。dtype 会根据是否有任何元素为复数而转换为 float64 或 complex128。如果 x 是标量,则将其转换为一维数组。参数 deg 是结果矩阵的次数。
步骤
首先,导入所需的库 -
import numpy as np from numpy.polynomial import chebyshev as C
创建数组 -
x = np.array([-2.+2.j, -1.+2.j, 0.+2.j, 1.+2.j, 2.+2.j])
显示数组 -
print("Our Array...\n",x)
检查维度 -
print("\nDimensions of our Array...\n",x.ndim)
获取数据类型 -
print("\nDatatype of our Array object...\n",x.dtype)
获取形状 -
print("\nShape of our Array object...\n",x.shape)
要生成切比雪夫多项式的范德蒙矩阵,请使用 chebyshev.chebvander() -
print("\nResult...\n",C.chebvander(x, 2))
示例
import numpy as np from numpy.polynomial import chebyshev as C # Create an array x = np.array([-2.+2.j, -1.+2.j, 0.+2.j, 1.+2.j, 2.+2.j]) # Display the array print("Our Array...\n",x) # Check the Dimensions print("\nDimensions of our Array...\n",x.ndim) # Get the Datatype print("\nDatatype of our Array object...\n",x.dtype) # Get the Shape print("\nShape of our Array object...\n",x.shape) # To generate a Vandermonde matrix of the Chebyshev polynomial, use the chebyshev.chebvander() in Python Numpy # The method returns the Vandermonde matrix. The shape of the returned matrix is x.shape + (deg + 1,), where The last index is the degree of the corresponding Chebyshev polynomial. The dtype will be the same as the converted x. # The parameter, a is Array of points. The dtype is converted to float64 or complex128 depending on whether any of the elements are complex. If x is scalar it is converted to a 1-D array. # The parameter, deg is the degree of the resulting matrix print("\nResult...\n",C.chebvander(x, 2))
输出
Our Array... [-2.+2.j -1.+2.j 0.+2.j 1.+2.j 2.+2.j] Dimensions of our Array... 1 Datatype of our Array object... complex128 Shape of our Array object... (5,) Result... [[ 1. +0.j -2. +2.j -1.-16.j] [ 1. +0.j -1. +2.j -7. -8.j] [ 1. +0.j 0. +2.j -9. +0.j] [ 1. +0.j 1. +2.j -7. +8.j] [ 1. +0.j 2. +2.j -1.+16.j]]
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