import numpy as np
from igakit.nurbs import *
k = np.array([[0,0,0,0.5,1,1,1]])
C = NURBS(k)
C.elevate(0,1)

Traceback (most recent call last):
  File "test.py", line 5, in <module>
    C.elevate(0,2)
  File "/home/usr/.local/lib/python3.8/site-packages/igakit/nurbs.py", line 1152, in elevate
    V, Qw = DegreeElevate(p, U, Pw, t)
igalib.error: (n>=1) failed for hidden n: DegreeElevate:n=-1

note: This error originates from a subprocess, and is likely not a problem with pip.
  ERROR: Failed building wheel for igakit
Failed to build igakit
ERROR: Could not build wheels for igakit, which is required to install pyproject.toml-based projects

from igakit.cad import circle
from numpy import pi 
c1 = circle(angle=(0,pi/2.))
print(c1.knots)
print(c1.control)
c2 = circle(radius=2,angle=(0,pi/2.))
from igakit.plot import plt
plt.curve(c1,color='b')
plt.curve(c2,color='g')
plt.show()

Traceback (most recent call last):
  File "/home/elbert5770/Documents/python/igakit_test.py", line 8, in <module>
    plt.curve(c1,color='b')
  File "/home/elbert5770/.local/lib/python3.10/site-packages/igakit/plot.py", line 213, in curve
    crv = self.backend.line3d(lines=lines, **options)
  File "/home/elbert5770/.local/lib/python3.10/site-packages/igakit/plot_mpl.py", line 67, in line3d
    ax = gca()
  File "/home/elbert5770/.local/lib/python3.10/site-packages/igakit/plot_mpl.py", line 19, in gca
    return gcf().gca(projection='3d', **kwargs)
TypeError: FigureBase.gca() got an unexpected keyword argument 'projection'