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numpy.linalg.det(and Cauchy matrix)

Last updated at 2017-12-28Posted at 2017-12-27

A = ((1,2),(2,3))
print(np.linalg.det(A))
X = np.arange(8)
Y = X + 0.5
C = 1.0 / np.subtract.outer(X, Y)
print(X)
print(Y)
print("====C====")
print(C)
print(np.linalg.det(C))

-1.0
[0 1 2 3 4 5 6 7]
[ 0.5  1.5  2.5  3.5  4.5  5.5  6.5  7.5]
====C====
[[-2.         -0.66666667 -0.4        -0.28571429 -0.22222222 -0.18181818
  -0.15384615 -0.13333333]
 [ 2.         -2.         -0.66666667 -0.4        -0.28571429 -0.22222222
  -0.18181818 -0.15384615]
 [ 0.66666667  2.         -2.         -0.66666667 -0.4        -0.28571429
  -0.22222222 -0.18181818]
 [ 0.4         0.66666667  2.         -2.         -0.66666667 -0.4
  -0.28571429 -0.22222222]
 [ 0.28571429  0.4         0.66666667  2.         -2.         -0.66666667
  -0.4        -0.28571429]
 [ 0.22222222  0.28571429  0.4         0.66666667  2.         -2.
  -0.66666667 -0.4       ]
 [ 0.18181818  0.22222222  0.28571429  0.4         0.66666667  2.         -2.
  -0.66666667]
 [ 0.15384615  0.18181818  0.22222222  0.28571429  0.4         0.66666667
   2.         -2.        ]]
3638.16363712

By the way, I can't understand the meaning of the determinant of Cauchy matrix, so please teach me about that.

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