Difference between power method and normalised power method












0














i've been trying to learn about power method. I don't understand why some people normalise the eigenvector and why some people just use a form of scaling. For example:



$bf{q^{(k)}} = frac{Abf{q^{(k-1)}}}{|Abf{q^{(k-1)}}|_2}$ being the normalised version.



$bf{q^{(k)}} = {Abf{q^{(k-1)}}}$ which is then scaled down by dividing by an element of $q$.



What effect will this have on finding the dominating eigenvalue? For example can you use the Rayleigh Quotient on either of the two eigenvectors? Many thanks.










share|cite|improve this question



























    0














    i've been trying to learn about power method. I don't understand why some people normalise the eigenvector and why some people just use a form of scaling. For example:



    $bf{q^{(k)}} = frac{Abf{q^{(k-1)}}}{|Abf{q^{(k-1)}}|_2}$ being the normalised version.



    $bf{q^{(k)}} = {Abf{q^{(k-1)}}}$ which is then scaled down by dividing by an element of $q$.



    What effect will this have on finding the dominating eigenvalue? For example can you use the Rayleigh Quotient on either of the two eigenvectors? Many thanks.










    share|cite|improve this question

























      0












      0








      0







      i've been trying to learn about power method. I don't understand why some people normalise the eigenvector and why some people just use a form of scaling. For example:



      $bf{q^{(k)}} = frac{Abf{q^{(k-1)}}}{|Abf{q^{(k-1)}}|_2}$ being the normalised version.



      $bf{q^{(k)}} = {Abf{q^{(k-1)}}}$ which is then scaled down by dividing by an element of $q$.



      What effect will this have on finding the dominating eigenvalue? For example can you use the Rayleigh Quotient on either of the two eigenvectors? Many thanks.










      share|cite|improve this question













      i've been trying to learn about power method. I don't understand why some people normalise the eigenvector and why some people just use a form of scaling. For example:



      $bf{q^{(k)}} = frac{Abf{q^{(k-1)}}}{|Abf{q^{(k-1)}}|_2}$ being the normalised version.



      $bf{q^{(k)}} = {Abf{q^{(k-1)}}}$ which is then scaled down by dividing by an element of $q$.



      What effect will this have on finding the dominating eigenvalue? For example can you use the Rayleigh Quotient on either of the two eigenvectors? Many thanks.







      linear-algebra eigenvalues-eigenvectors






      share|cite|improve this question













      share|cite|improve this question











      share|cite|improve this question




      share|cite|improve this question










      asked Nov 29 at 0:29









      kp1897

      11




      11



























          active

          oldest

          votes











          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',
          autoActivateHeartbeat: false,
          convertImagesToLinks: true,
          noModals: true,
          showLowRepImageUploadWarning: true,
          reputationToPostImages: 10,
          bindNavPrevention: true,
          postfix: "",
          imageUploader: {
          brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
          contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/3.0/"u003ecc by-sa 3.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
          allowUrls: true
          },
          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%2f3017984%2fdifference-between-power-method-and-normalised-power-method%23new-answer', 'question_page');
          }
          );

          Post as a guest















          Required, but never shown






























          active

          oldest

          votes













          active

          oldest

          votes









          active

          oldest

          votes






          active

          oldest

          votes
















          draft saved

          draft discarded




















































          Thanks for contributing an answer to Mathematics Stack Exchange!


          • Please be sure to answer the question. Provide details and share your research!

          But avoid



          • Asking for help, clarification, or responding to other answers.

          • Making statements based on opinion; back them up with references or personal experience.


          Use MathJax to format equations. MathJax reference.


          To learn more, see our tips on writing great answers.





          Some of your past answers have not been well-received, and you're in danger of being blocked from answering.


          Please pay close attention to the following guidance:


          • Please be sure to answer the question. Provide details and share your research!

          But avoid



          • Asking for help, clarification, or responding to other answers.

          • Making statements based on opinion; back them up with references or personal experience.


          To learn more, see our tips on writing great answers.




          draft saved


          draft discarded














          StackExchange.ready(
          function () {
          StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fmath.stackexchange.com%2fquestions%2f3017984%2fdifference-between-power-method-and-normalised-power-method%23new-answer', 'question_page');
          }
          );

          Post as a guest















          Required, but never shown





















































          Required, but never shown














          Required, but never shown












          Required, but never shown







          Required, but never shown

































          Required, but never shown














          Required, but never shown












          Required, but never shown







          Required, but never shown







          Popular posts from this blog

          Wiesbaden

          Marschland

          Dieringhausen