Evaluate a 2-D polynomial at points (x, y) in Python

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. Parameters, x, y. The two dimensional series is evaluated at the points (x, y), where x and y must have the same shape. If x or y is a list or tuple, it is first converted to an ndarray, otherwise it is left unchanged and, if it isn’t an ndarray, it is treated as a scalar.

The parameter, c is an Array of coefficients ordered so that the coefficient of the term of multidegree i,j is contained in c[i,j]. If c has dimension greater than two the remaining indices enumerate multiple sets of coefficients. If c has fewer than two dimensions, ones are implicitly appended to its shape to make it 2-D. The shape of the result will be c.shape[2:] + x.shape.

Steps

At first, import the required libraries −

import numpy as np from numpy.polynomial.polynomial import polyval2d

Create a multidimensional array of coefficients −

c = np.arange(4).reshape(2,2)

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 −

print("\nResult...\n",polyval2d([1,2],[1,2], c))

Example

import numpy as np from numpy.polynomial.polynomial import polyval2d # Create a multidimensional array of coefficients c = np.arange(4).reshape(2,2) # 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 print("\nResult...\n",polyval2d([1,2],[1,2], c))

Output

Our Array... [[0 1]    [2 3]] Dimensions of our Array... 2 Datatype of our Array object... int64 Shape of our Array object... (2, 2) Result... [ 6. 18.]