Python | Numpy np.polyvander2d() method (original) (raw)

Last Updated : 31 Dec, 2019

With the help of **np.polyvander2d()** method, we can get the Pseudo-Vandermonde matrix from given array having degree which is passed as parameter by using np.polyvander2d() method.

Syntax : np.polyvander2d(x, y, deg) Parameters: **x, y :[ array_like ] Array of points. The dtype is converted to float64 or complex128 depending on whether any of the elements are complex. If x is scalar it is converted to a 1-D arraydeg :**[int] Degree of the resulting matrix.Return : Return the matrix having size i.e array.size + (degree + 1).

**Example #1 :**In this example we can see that by using np.polyvander2d() method, we are able to get the pseudo-vandermonde matrix using this method.

Python3 1=1 `

import numpy

import numpy as np import numpy.polynomial.polynomial as geek

using np.polyvander() method

ans = geek.polyvander2d((1, 3, 5, 7), (2, 4, 6, 8), [2, 2])

print(ans)

`

Output :

[[ 1.00000000e+00 2.00000000e+00 4.00000000e+00 1.00000000e+00 2.00000000e+00 4.00000000e+00 1.00000000e+00 2.00000000e+00 4.00000000e+00] [ 1.00000000e+00 4.00000000e+00 1.60000000e+01 3.00000000e+00 1.20000000e+01 4.80000000e+01 9.00000000e+00 3.60000000e+01 1.44000000e+02] [ 1.00000000e+00 6.00000000e+00 3.60000000e+01 5.00000000e+00 3.00000000e+01 1.80000000e+02 2.50000000e+01 1.50000000e+02 9.00000000e+02] [ 1.00000000e+00 8.00000000e+00 6.40000000e+01 7.00000000e+00 5.60000000e+01 4.48000000e+02 4.90000000e+01 3.92000000e+02 3.13600000e+03]]

Example #2 :

Python3 1=1 `

import numpy

import numpy as np import numpy.polynomial.polynomial as geek

ans = geek.polyvander2d((1, 2, 3, 4), (5, 6, 7, 8), [3, 3])

print(ans)

`

Output :

[[ 1.00000000e+00 5.00000000e+00 2.50000000e+01 1.25000000e+02 1.00000000e+00 5.00000000e+00 2.50000000e+01 1.25000000e+02 1.00000000e+00 5.00000000e+00 2.50000000e+01 1.25000000e+02 1.00000000e+00 5.00000000e+00 2.50000000e+01 1.25000000e+02] [ 1.00000000e+00 6.00000000e+00 3.60000000e+01 2.16000000e+02 2.00000000e+00 1.20000000e+01 7.20000000e+01 4.32000000e+02 4.00000000e+00 2.40000000e+01 1.44000000e+02 8.64000000e+02 8.00000000e+00 4.80000000e+01 2.88000000e+02 1.72800000e+03] [ 1.00000000e+00 7.00000000e+00 4.90000000e+01 3.43000000e+02 3.00000000e+00 2.10000000e+01 1.47000000e+02 1.02900000e+03 9.00000000e+00 6.30000000e+01 4.41000000e+02 3.08700000e+03 2.70000000e+01 1.89000000e+02 1.32300000e+03 9.26100000e+03] [ 1.00000000e+00 8.00000000e+00 6.40000000e+01 5.12000000e+02 4.00000000e+00 3.20000000e+01 2.56000000e+02 2.04800000e+03 1.60000000e+01 1.28000000e+02 1.02400000e+03 8.19200000e+03 6.40000000e+01 5.12000000e+02 4.09600000e+03 3.27680000e+04]]

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