使用Python生成指定階數的偽範德蒙德矩陣,其中包含浮點型陣列的點座標


要生成指定階數的偽範德蒙德矩陣,可以使用Python NumPy中的`polynomial.polyvander2()`。此方法返回指定階數`deg`和取樣點(x, y)的偽範德蒙德矩陣。

引數x和y是點座標陣列,形狀相同。資料型別將轉換為float64或complex128,具體取決於元素是否為複數。標量將轉換為一維陣列。引數deg是最大階數列表,格式為[x_deg, y_deg]。

步驟

首先,匯入所需的庫:

import numpy as np
from numpy.polynomial.polynomial import polyvander2d

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)

要生成指定階數的偽範德蒙德矩陣,請使用`polynomial.polyvander2()`:

x_deg, y_deg = 2, 3
print("\nResult...\n",polyvander2d(x,y, [x_deg, y_deg]))

示例

import numpy as np
from numpy.polynomial.polynomial import polyvander2d

# 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 given degree, use the polynomial.polyvander2() in Python Numpy
# The method returns the pseudo-Vandermonde matrix of degrees deg and sample points (x, y).
x_deg, y_deg = 2, 3
print("\nResult...\n",polyvander2d(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...
   [[1.000000e+00 1.700000e+00 2.890000e+00 4.913000e+00 1.000000e-01
      1.700000e-01 2.890000e-01 4.913000e-01 1.000000e-02 1.700000e-02
      2.890000e-02 4.913000e-02]
   [1.000000e+00 2.800000e+00 7.840000e+00 2.195200e+01 1.400000e+00
      3.920000e+00 1.097600e+01 3.073280e+01 1.960000e+00 5.488000e+00
      1.536640e+01 4.302592e+01]]

更新於:2022年3月1日

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