# Evaluate a 3-D Chebyshev series on the Cartesian product of x, y and z in Python

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To evaluate a 3-D Chebyshev series on the Cartesian product of x, y, z, use the polynomial.chebgrid3d(x, y, z) method in Python. If c has fewer than three dimensions, ones are implicitly appended to its shape to make it 3-D. The shape of the result will be c.shape[3:] + x.shape + y.shape + z.shape.

The parameter, x, y and z are the three dimensional series is evaluated at the points in the Cartesian product of x, y, and z. If x,y, or z 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 coefficients for terms of degree i,j are contained in c[i,j]. If c has dimension greater than two the remaining indices enumerate multiple sets of coefficients.

## Steps

At first, import the required libraries −

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

Create a 3D array of coefficients −

c = np.arange(16).reshape(2,2,4)

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 3-D Chebyshev series on the Cartesian product of x, y, z, use the polynomial.chebgrid3d(x, y, z) method −

print("\nResult...\n",C.chebgrid3d([1,2],[1,2],[1,2], c))

## Example

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

# Create a 3D array of coefficients
c = np.arange(16).reshape(2,2,4)

# 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 3-D Chebyshev series on the Cartesian product of x, y, z, use the polynomial.chebgrid3d(x, y, z) method in Python
print("\nResult...\n",C.chebgrid3d([1,2],[1,2],[1,2], c))

## Output

Our Array...
[[[ 0 1 2 3]
[ 4 5 6 7]]

[[ 8 9 10 11]
[12 13 14 15]]]

Dimensions of our Array...
3

Datatype of our Array object...
int64

Shape of our Array object...
(2, 2, 4)

Result...
[[[ 120. 1240.]
[ 196. 2004.]]

[[ 212. 2148.]
[ 342. 3438.]]]