I'm new to NumPy, a problem blocks me.. --- I want to change a ndarray's value:
Here is the debug info.
(Pdb) Nodes[0,0]['f'] = np.array([i/9.0 for i in range(9)])
(Pdb) print Nodes[0,0]['f']
[ 0.00000000e+00 0.00000000e+00 5.67382835e+10 4.58280650e-41
1.00030523e-36 0.00000000e+00 1.00030523e-36 0.00000000e+00
2.28153811e-40]
(Pdb)
Why doesn't the value of Node[0,0]['f'] change?
Try using Nodes['f'][0,0] = numpy.array([i/9.0 for i in range(9)]) instead:
import numpy
Nodes = numpy.ndarray(shape=(1,1), dtype=[('f', (float, 9))])
print Nodes[0,0]['f']
# [ 0.00000000e+000 2.10042365e-316 2.44222340e-316 6.90749588e-310
# 2.10041417e-316 4.22653002e-317 2.76341350e-316 6.90749588e-310
# 3.95252517e-322]
Nodes[0,0]['f'] = numpy.array([i/9.0 for i in range(9)])
print Nodes[0,0]['f']
# [ 0.00000000e+000 2.10042365e-316 2.44222340e-316 6.90749588e-310
# 2.10041417e-316 4.22653002e-317 2.76341350e-316 6.90749588e-310
# 3.95252517e-322]
Nodes['f'][0,0] = numpy.array([i/9.0 for i in range(9)])
print Nodes[0,0]['f']
# [ 0. 0.11111111 0.22222222 0.33333333 0.44444444 0.55555556
# 0.66666667 0.77777778 0.88888889]
I'm not sure why there's a difference, but it is probably related to this question.
