使用Python和一维系数数组评估二维多项式在(x, y)点的值
为了评估二维多项式在点(x, y)的值,可以使用Python NumPy中的`polynomial.polyval2d()`方法。该方法返回在由x和y的对应值对形成的点上二维多项式的值,即参数x, y。二维序列在点(x, y)处进行评估,其中x和y必须具有相同的形状。如果x或y是列表或元组,则首先将其转换为ndarray,否则保持不变,如果它不是ndarray,则将其视为标量。
参数c是一个系数数组,其顺序使得多度为i,j的项的系数包含在c[i,j]中。如果c的维度大于二,则其余索引枚举多个系数集。如果c的维度小于二,则会隐式地将其形状附加为2-D。结果的形状将为c.shape[2:] + x.shape。如果c的维度小于二,则会隐式地将其形状附加为2-D。结果的形状将为c.shape[2:] + x.shape。
步骤
首先,导入所需的库:
import numpy as np from numpy.polynomial.polynomial import polyval2d
创建一个一维系数数组:
c = np.array([3, 5])
显示数组:
print("Our Array...\n",c)
检查维度:
print("\nDimensions of our Array...\n",c.ndim)
获取数据类型:
print("\nDatatype of our Array object...\n",c.dtype)
获取形状:
print("\nShape of our Array object...\n",c.shape)
为了评估二维多项式在点(x, y)的值,可以使用Python NumPy中的`polynomial.polyval2d()`方法。该方法返回在由x和y的对应值对形成的点上二维多项式的值:
print("\nResult...\n",polyval2d([1,2],[1,2], c))
示例
import numpy as np from numpy.polynomial.polynomial import polyval2d # Create a 1d array of coefficients c = np.array([3, 5]) # Display the array print("Our Array...\n",c) # Check the Dimensions print("\nDimensions of our Array...\n",c.ndim) # Get the Datatype print("\nDatatype of our Array object...\n",c.dtype) # Get the Shape print("\nShape of our Array object...\n",c.shape) # To evaluate a 2-D polynomial at points (x, y), use the polynomial.polyval2d() method in Python Numpy # The method returns the values of the two dimensional polynomial at points formed with pairs of corresponding values from x and y. print("\nResult...\n",polyval2d([1,2],[1,2], c))
输出
Our Array... [3 5] Dimensions of our Array... 1 Datatype of our Array object... int64 Shape of our Array object... (2,) Result... [21. 34.]
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