Any O(N^2) method for finding the eigenvalues of J-Hermitian (complex Hamiltonian) matrix?

The name of the pictureThe name of the pictureThe name of the pictureClash Royale CLAN TAG#URR8PPP











up vote
1
down vote

favorite












I came across the problem of finding the eigenvalue spectrum of a general J-Hermitian (complex Hamiltonian) matrix. Is there any method (available algorithms) that would work faster than the "standard" methods for finding the eigenvalues of non-structured (no symmetry) complex-valued matrices (the number of flops is O(N^3), with N being the dimension of the matrix). In the picture below $gamma_k$ are the complex Fourier-expansion coefficients of some given complex-valued functionHere is the part of the paper text where that matrix eigenproblem is defined with more details regarding its elements and structure







share|cite|improve this question























    up vote
    1
    down vote

    favorite












    I came across the problem of finding the eigenvalue spectrum of a general J-Hermitian (complex Hamiltonian) matrix. Is there any method (available algorithms) that would work faster than the "standard" methods for finding the eigenvalues of non-structured (no symmetry) complex-valued matrices (the number of flops is O(N^3), with N being the dimension of the matrix). In the picture below $gamma_k$ are the complex Fourier-expansion coefficients of some given complex-valued functionHere is the part of the paper text where that matrix eigenproblem is defined with more details regarding its elements and structure







    share|cite|improve this question





















      up vote
      1
      down vote

      favorite









      up vote
      1
      down vote

      favorite











      I came across the problem of finding the eigenvalue spectrum of a general J-Hermitian (complex Hamiltonian) matrix. Is there any method (available algorithms) that would work faster than the "standard" methods for finding the eigenvalues of non-structured (no symmetry) complex-valued matrices (the number of flops is O(N^3), with N being the dimension of the matrix). In the picture below $gamma_k$ are the complex Fourier-expansion coefficients of some given complex-valued functionHere is the part of the paper text where that matrix eigenproblem is defined with more details regarding its elements and structure







      share|cite|improve this question











      I came across the problem of finding the eigenvalue spectrum of a general J-Hermitian (complex Hamiltonian) matrix. Is there any method (available algorithms) that would work faster than the "standard" methods for finding the eigenvalues of non-structured (no symmetry) complex-valued matrices (the number of flops is O(N^3), with N being the dimension of the matrix). In the picture below $gamma_k$ are the complex Fourier-expansion coefficients of some given complex-valued functionHere is the part of the paper text where that matrix eigenproblem is defined with more details regarding its elements and structure









      share|cite|improve this question










      share|cite|improve this question




      share|cite|improve this question









      asked Aug 1 at 20:08









      Yary Prilly

      61




      61




















          1 Answer
          1






          active

          oldest

          votes

















          up vote
          0
          down vote













          The complexity of the eigenvalue problem for complex Hamiltonian matrices has been studied in A Note on the Numerical Solution of Complex Hamiltonian and Skew-Hamiltonian Eigenvalue Problems. There is no improvement over the usual $N^3$ complexity, however, what you can achieve is an algorithm that respects the structure of the matrix, so that if $lambda$ is an eigenvalue also $-barlambda$ is one. In particular, the routine returns eigenvalues with real part exactly equal to zero.






          share|cite|improve this answer





















          • Thank you. I have also seen some works related to the structure preserving methods, and I though that maybe if we forget about the structure preservation, we can have something faster
            – Yary Prilly
            Aug 3 at 12:14










          Your Answer




          StackExchange.ifUsing("editor", function ()
          return StackExchange.using("mathjaxEditing", function ()
          StackExchange.MarkdownEditor.creationCallbacks.add(function (editor, postfix)
          StackExchange.mathjaxEditing.prepareWmdForMathJax(editor, postfix, [["$", "$"], ["\\(","\\)"]]);
          );
          );
          , "mathjax-editing");

          StackExchange.ready(function()
          var channelOptions =
          tags: "".split(" "),
          id: "69"
          ;
          initTagRenderer("".split(" "), "".split(" "), channelOptions);

          StackExchange.using("externalEditor", function()
          // Have to fire editor after snippets, if snippets enabled
          if (StackExchange.settings.snippets.snippetsEnabled)
          StackExchange.using("snippets", function()
          createEditor();
          );

          else
          createEditor();

          );

          function createEditor()
          StackExchange.prepareEditor(
          heartbeatType: 'answer',
          convertImagesToLinks: true,
          noModals: false,
          showLowRepImageUploadWarning: true,
          reputationToPostImages: 10,
          bindNavPrevention: true,
          postfix: "",
          noCode: true, onDemand: true,
          discardSelector: ".discard-answer"
          ,immediatelyShowMarkdownHelp:true
          );



          );








           

          draft saved


          draft discarded


















          StackExchange.ready(
          function ()
          StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fmath.stackexchange.com%2fquestions%2f2869474%2fany-on2-method-for-finding-the-eigenvalues-of-j-hermitian-complex-hamiltonia%23new-answer', 'question_page');

          );

          Post as a guest






























          1 Answer
          1






          active

          oldest

          votes








          1 Answer
          1






          active

          oldest

          votes









          active

          oldest

          votes






          active

          oldest

          votes








          up vote
          0
          down vote













          The complexity of the eigenvalue problem for complex Hamiltonian matrices has been studied in A Note on the Numerical Solution of Complex Hamiltonian and Skew-Hamiltonian Eigenvalue Problems. There is no improvement over the usual $N^3$ complexity, however, what you can achieve is an algorithm that respects the structure of the matrix, so that if $lambda$ is an eigenvalue also $-barlambda$ is one. In particular, the routine returns eigenvalues with real part exactly equal to zero.






          share|cite|improve this answer





















          • Thank you. I have also seen some works related to the structure preserving methods, and I though that maybe if we forget about the structure preservation, we can have something faster
            – Yary Prilly
            Aug 3 at 12:14














          up vote
          0
          down vote













          The complexity of the eigenvalue problem for complex Hamiltonian matrices has been studied in A Note on the Numerical Solution of Complex Hamiltonian and Skew-Hamiltonian Eigenvalue Problems. There is no improvement over the usual $N^3$ complexity, however, what you can achieve is an algorithm that respects the structure of the matrix, so that if $lambda$ is an eigenvalue also $-barlambda$ is one. In particular, the routine returns eigenvalues with real part exactly equal to zero.






          share|cite|improve this answer





















          • Thank you. I have also seen some works related to the structure preserving methods, and I though that maybe if we forget about the structure preservation, we can have something faster
            – Yary Prilly
            Aug 3 at 12:14












          up vote
          0
          down vote










          up vote
          0
          down vote









          The complexity of the eigenvalue problem for complex Hamiltonian matrices has been studied in A Note on the Numerical Solution of Complex Hamiltonian and Skew-Hamiltonian Eigenvalue Problems. There is no improvement over the usual $N^3$ complexity, however, what you can achieve is an algorithm that respects the structure of the matrix, so that if $lambda$ is an eigenvalue also $-barlambda$ is one. In particular, the routine returns eigenvalues with real part exactly equal to zero.






          share|cite|improve this answer













          The complexity of the eigenvalue problem for complex Hamiltonian matrices has been studied in A Note on the Numerical Solution of Complex Hamiltonian and Skew-Hamiltonian Eigenvalue Problems. There is no improvement over the usual $N^3$ complexity, however, what you can achieve is an algorithm that respects the structure of the matrix, so that if $lambda$ is an eigenvalue also $-barlambda$ is one. In particular, the routine returns eigenvalues with real part exactly equal to zero.







          share|cite|improve this answer













          share|cite|improve this answer



          share|cite|improve this answer











          answered Aug 1 at 20:59









          Carlo Beenakker

          42448




          42448











          • Thank you. I have also seen some works related to the structure preserving methods, and I though that maybe if we forget about the structure preservation, we can have something faster
            – Yary Prilly
            Aug 3 at 12:14
















          • Thank you. I have also seen some works related to the structure preserving methods, and I though that maybe if we forget about the structure preservation, we can have something faster
            – Yary Prilly
            Aug 3 at 12:14















          Thank you. I have also seen some works related to the structure preserving methods, and I though that maybe if we forget about the structure preservation, we can have something faster
          – Yary Prilly
          Aug 3 at 12:14




          Thank you. I have also seen some works related to the structure preserving methods, and I though that maybe if we forget about the structure preservation, we can have something faster
          – Yary Prilly
          Aug 3 at 12:14












           

          draft saved


          draft discarded


























           


          draft saved


          draft discarded














          StackExchange.ready(
          function ()
          StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fmath.stackexchange.com%2fquestions%2f2869474%2fany-on2-method-for-finding-the-eigenvalues-of-j-hermitian-complex-hamiltonia%23new-answer', 'question_page');

          );

          Post as a guest













































































          Comments

          Popular posts from this blog

          What is the equation of a 3D cone with generalised tilt?

          Color the edges and diagonals of a regular polygon

          Relationship between determinant of matrix and determinant of adjoint?