使用Python生成Chebyshev多項式的偽Vandermonde矩陣,該矩陣基於浮點型陣列的點座標


要生成Chebyshev多項式的偽Vandermonde矩陣,請在Python NumPy中使用`chebyshev.chebvander()`。該方法返回度數為deg和取樣點(x, y)的偽Vandermonde矩陣。引數x、y是點座標陣列,形狀相同。資料型別將根據元素是否為複數轉換為float64或complex128。標量將轉換為一維陣列。引數deg是最大度數列表,形式為[x_deg, y_deg]。

步驟

首先,匯入所需的庫:

import numpy as np
from numpy.polynomial import chebyshev as C

使用`numpy.array()`方法建立形狀相同的點座標陣列:

x = np.array([0.1, 1.4])
y = np.array([1.7, 2.8])

顯示陣列:

print("Array1...\n",x)
print("\nArray2...\n",y)

顯示資料型別:

print("\nArray1 datatype...\n",x.dtype)
print("\nArray2 datatype...\n",y.dtype)

檢查兩個陣列的維度:

print("\nDimensions of Array1...\n",x.ndim)
print("\nDimensions of Array2...\n",y.ndim)

檢查兩個陣列的形狀:

print("\nShape of Array1...\n",x.shape)
print("\nShape of Array2...\n",y.shape)

要生成Chebyshev多項式的偽Vandermonde矩陣,請在Python中使用`chebyshev.chebvander()`:

x_deg, y_deg = 2, 3
print("\nResult...\n",C.chebvander2d(x,y, [x_deg, y_deg]))

示例

import numpy as np
from numpy.polynomial import chebyshev as C

# 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 Chebyshev polynomial, use the chebyshev.chebvander() in Python Numpy
x_deg, y_deg = 2, 3
print("\nResult...\n",C.chebvander2d(x,y, [x_deg, y_deg]))

輸出

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 4.7800000e+00 1.4552000e+01
1.0000000e-01 1.7000000e-01 4.7800000e-01 1.4552000e+00
-9.8000000e-01 -1.6660000e+00 -4.6844000e+00 -1.4260960e+01]
[ 1.0000000e+00 2.8000000e+00 1.4680000e+01 7.9408000e+01
1.4000000e+00 3.9200000e+00 2.0552000e+01 1.1117120e+02
2.9200000e+00 8.1760000e+00 4.2865600e+01 2.3187136e+02]]

更新於:2022年2月28日

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