CoCalc -- 1947.sagews

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Path: pub / 1901-2001 / 1947.sagews

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A = matrix(RR, 4, [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16]); A

[1.00000000000000 2.00000000000000 3.00000000000000 4.00000000000000]
[5.00000000000000 6.00000000000000 7.00000000000000 8.00000000000000]
[9.00000000000000 10.0000000000000 11.0000000000000 12.0000000000000]
[13.0000000000000 14.0000000000000 15.0000000000000 16.0000000000000]

A.eigenvalues()

__main__:1: UserWarning: Using generic algorithm for an inexact ring, which will probably give incorrect results due to numerical precision issues.
[36.2093727122985, -0.000000000000000, -0.000000000000000, -2.20937271229855]

x = var('x')
B = matrix(RR['x'], 2, [x^2 + 1, x^2 - 1, x + 1, x - 1]); B

[x^2 + 1.00000000000000 x^2 - 1.00000000000000]
[  x + 1.00000000000000   x - 1.00000000000000]

B.eigenvalues()

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "_sage_input_14.py", line 9, in <module>
    exec compile(ur'open("___code___.py","w").write("# -*- coding: utf-8 -*-\n" + _support_.preparse_worksheet_cell(base64.b64decode("Qi5laWdlbnZhbHVlcygp"),globals())+"\n"); execfile(os.path.abspath("___code___.py"))' + '\n', '', 'single')
  File "", line 1, in <module>
    
  File "/tmp/tmpxlZEpN/___code___.py", line 2, in <module>
    exec compile(ur'B.eigenvalues()' + '\n', '', 'single')
  File "", line 1, in <module>
    
  File "matrix2.pyx", line 3774, in sage.matrix.matrix2.Matrix.eigenvalues (sage/matrix/matrix2.c:21821)
  File "matrix2.pyx", line 1655, in sage.matrix.matrix2.Matrix.fcp (sage/matrix/matrix2.c:10386)
  File "polynomial_element.pyx", line 2733, in sage.rings.polynomial.polynomial_element.Polynomial.factor (sage/rings/polynomial/polynomial_element.c:22092)
NotImplementedError