Equality constrained least squares problem: How to minimize the distance from a set of points to a point on a...












-1












$begingroup$


Equality constrained least squares problem: Given is a set of N points Pi and a line in R^3. Find a point P on the line that minimizes Minimizing this sum.










share|cite|improve this question









$endgroup$

















    -1












    $begingroup$


    Equality constrained least squares problem: Given is a set of N points Pi and a line in R^3. Find a point P on the line that minimizes Minimizing this sum.










    share|cite|improve this question









    $endgroup$















      -1












      -1








      -1





      $begingroup$


      Equality constrained least squares problem: Given is a set of N points Pi and a line in R^3. Find a point P on the line that minimizes Minimizing this sum.










      share|cite|improve this question









      $endgroup$




      Equality constrained least squares problem: Given is a set of N points Pi and a line in R^3. Find a point P on the line that minimizes Minimizing this sum.







      linear-algebra numerical-methods computer-science






      share|cite|improve this question













      share|cite|improve this question











      share|cite|improve this question




      share|cite|improve this question










      asked Jan 11 at 19:06









      Sebastian RedlSebastian Redl

      1




      1






















          1 Answer
          1






          active

          oldest

          votes


















          0












          $begingroup$

          Note that your expression means you're minimizing the sum of the squares of the distances, not the sum of the distances



          Without the constraint, the point in R^3 that would minimize the sum is simply the mean of the points, the centroid. When you move away from the centroid, you start to induce a penalty. Expanding squares quickly shows that it doesn't matter which way you deviate from the mean, just by how much. So, "move" your solution onto the line.



          That is really say, the solution: compute the mean of your points. Project that to the line (i.e. the point on the line closest to the mean). This is your optimum.






          share|cite|improve this answer









          $endgroup$













            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%2f3070226%2fequality-constrained-least-squares-problem-how-to-minimize-the-distance-from-a%23new-answer', 'question_page');
            }
            );

            Post as a guest















            Required, but never shown

























            1 Answer
            1






            active

            oldest

            votes








            1 Answer
            1






            active

            oldest

            votes









            active

            oldest

            votes






            active

            oldest

            votes









            0












            $begingroup$

            Note that your expression means you're minimizing the sum of the squares of the distances, not the sum of the distances



            Without the constraint, the point in R^3 that would minimize the sum is simply the mean of the points, the centroid. When you move away from the centroid, you start to induce a penalty. Expanding squares quickly shows that it doesn't matter which way you deviate from the mean, just by how much. So, "move" your solution onto the line.



            That is really say, the solution: compute the mean of your points. Project that to the line (i.e. the point on the line closest to the mean). This is your optimum.






            share|cite|improve this answer









            $endgroup$


















              0












              $begingroup$

              Note that your expression means you're minimizing the sum of the squares of the distances, not the sum of the distances



              Without the constraint, the point in R^3 that would minimize the sum is simply the mean of the points, the centroid. When you move away from the centroid, you start to induce a penalty. Expanding squares quickly shows that it doesn't matter which way you deviate from the mean, just by how much. So, "move" your solution onto the line.



              That is really say, the solution: compute the mean of your points. Project that to the line (i.e. the point on the line closest to the mean). This is your optimum.






              share|cite|improve this answer









              $endgroup$
















                0












                0








                0





                $begingroup$

                Note that your expression means you're minimizing the sum of the squares of the distances, not the sum of the distances



                Without the constraint, the point in R^3 that would minimize the sum is simply the mean of the points, the centroid. When you move away from the centroid, you start to induce a penalty. Expanding squares quickly shows that it doesn't matter which way you deviate from the mean, just by how much. So, "move" your solution onto the line.



                That is really say, the solution: compute the mean of your points. Project that to the line (i.e. the point on the line closest to the mean). This is your optimum.






                share|cite|improve this answer









                $endgroup$



                Note that your expression means you're minimizing the sum of the squares of the distances, not the sum of the distances



                Without the constraint, the point in R^3 that would minimize the sum is simply the mean of the points, the centroid. When you move away from the centroid, you start to induce a penalty. Expanding squares quickly shows that it doesn't matter which way you deviate from the mean, just by how much. So, "move" your solution onto the line.



                That is really say, the solution: compute the mean of your points. Project that to the line (i.e. the point on the line closest to the mean). This is your optimum.







                share|cite|improve this answer












                share|cite|improve this answer



                share|cite|improve this answer










                answered Jan 11 at 19:13









                Alex MeiburgAlex Meiburg

                1,820517




                1,820517






























                    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.




                    draft saved


                    draft discarded














                    StackExchange.ready(
                    function () {
                    StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fmath.stackexchange.com%2fquestions%2f3070226%2fequality-constrained-least-squares-problem-how-to-minimize-the-distance-from-a%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

                    'app-layout' is not a known element: how to share Component with different Modules

                    android studio warns about leanback feature tag usage required on manifest while using Unity exported app?

                    SQL update select statement