Converting from “matrix” data into “coordinate” data












4












$begingroup$


Say I have data which looks like data1 - this is "matrix" like data (is there a better descriptor?). The data looks like a matrix, and at each point in the matrix, it has a value. I can plot these in ListContourPlot and the like. e.g.



datafunction = MultinormalDistribution[{0, 0}, {{2, 1/2}, {1/2, 1}}];

(* matrix like data *)

data1 = N[ Table[PDF[datafunction, {x, y}] /. {x -> xinsert, y -> yinsert}, {xinsert, -4, 4, 1}, {yinsert, -2, 2, 1}]];
ListContourPlot[data1]


enter image description here
However, I can also create the same effect by making "coordinate" like data, where the data is a list of coordinates.



(* coordinate like data *) 

data2 = RandomVariate[MultinormalDistribution[{0, 0}, {{2, 1/2}, {1/2, 1}}], 1000];
ListPlot[data2]


enter image description here
How would I convert data1 into data2? How do I convert matrix-like into coordinate-like?



I need to do some PCA analysis, I require the data to be in the form of individual points.










share|improve this question











$endgroup$








  • 2




    $begingroup$
    How do you think one could infer the individual counts from a total count? Once we have totaled data and thrown away the parts there is no way to reconstruct them. The mapping between sums and their constituents is not bijective.
    $endgroup$
    – Sjoerd C. de Vries
    13 hours ago
















4












$begingroup$


Say I have data which looks like data1 - this is "matrix" like data (is there a better descriptor?). The data looks like a matrix, and at each point in the matrix, it has a value. I can plot these in ListContourPlot and the like. e.g.



datafunction = MultinormalDistribution[{0, 0}, {{2, 1/2}, {1/2, 1}}];

(* matrix like data *)

data1 = N[ Table[PDF[datafunction, {x, y}] /. {x -> xinsert, y -> yinsert}, {xinsert, -4, 4, 1}, {yinsert, -2, 2, 1}]];
ListContourPlot[data1]


enter image description here
However, I can also create the same effect by making "coordinate" like data, where the data is a list of coordinates.



(* coordinate like data *) 

data2 = RandomVariate[MultinormalDistribution[{0, 0}, {{2, 1/2}, {1/2, 1}}], 1000];
ListPlot[data2]


enter image description here
How would I convert data1 into data2? How do I convert matrix-like into coordinate-like?



I need to do some PCA analysis, I require the data to be in the form of individual points.










share|improve this question











$endgroup$








  • 2




    $begingroup$
    How do you think one could infer the individual counts from a total count? Once we have totaled data and thrown away the parts there is no way to reconstruct them. The mapping between sums and their constituents is not bijective.
    $endgroup$
    – Sjoerd C. de Vries
    13 hours ago














4












4








4





$begingroup$


Say I have data which looks like data1 - this is "matrix" like data (is there a better descriptor?). The data looks like a matrix, and at each point in the matrix, it has a value. I can plot these in ListContourPlot and the like. e.g.



datafunction = MultinormalDistribution[{0, 0}, {{2, 1/2}, {1/2, 1}}];

(* matrix like data *)

data1 = N[ Table[PDF[datafunction, {x, y}] /. {x -> xinsert, y -> yinsert}, {xinsert, -4, 4, 1}, {yinsert, -2, 2, 1}]];
ListContourPlot[data1]


enter image description here
However, I can also create the same effect by making "coordinate" like data, where the data is a list of coordinates.



(* coordinate like data *) 

data2 = RandomVariate[MultinormalDistribution[{0, 0}, {{2, 1/2}, {1/2, 1}}], 1000];
ListPlot[data2]


enter image description here
How would I convert data1 into data2? How do I convert matrix-like into coordinate-like?



I need to do some PCA analysis, I require the data to be in the form of individual points.










share|improve this question











$endgroup$




Say I have data which looks like data1 - this is "matrix" like data (is there a better descriptor?). The data looks like a matrix, and at each point in the matrix, it has a value. I can plot these in ListContourPlot and the like. e.g.



datafunction = MultinormalDistribution[{0, 0}, {{2, 1/2}, {1/2, 1}}];

(* matrix like data *)

data1 = N[ Table[PDF[datafunction, {x, y}] /. {x -> xinsert, y -> yinsert}, {xinsert, -4, 4, 1}, {yinsert, -2, 2, 1}]];
ListContourPlot[data1]


enter image description here
However, I can also create the same effect by making "coordinate" like data, where the data is a list of coordinates.



(* coordinate like data *) 

data2 = RandomVariate[MultinormalDistribution[{0, 0}, {{2, 1/2}, {1/2, 1}}], 1000];
ListPlot[data2]


enter image description here
How would I convert data1 into data2? How do I convert matrix-like into coordinate-like?



I need to do some PCA analysis, I require the data to be in the form of individual points.







list-manipulation data-structures






share|improve this question















share|improve this question













share|improve this question




share|improve this question








edited 12 hours ago







Tomi

















asked 14 hours ago









TomiTomi

984514




984514








  • 2




    $begingroup$
    How do you think one could infer the individual counts from a total count? Once we have totaled data and thrown away the parts there is no way to reconstruct them. The mapping between sums and their constituents is not bijective.
    $endgroup$
    – Sjoerd C. de Vries
    13 hours ago














  • 2




    $begingroup$
    How do you think one could infer the individual counts from a total count? Once we have totaled data and thrown away the parts there is no way to reconstruct them. The mapping between sums and their constituents is not bijective.
    $endgroup$
    – Sjoerd C. de Vries
    13 hours ago








2




2




$begingroup$
How do you think one could infer the individual counts from a total count? Once we have totaled data and thrown away the parts there is no way to reconstruct them. The mapping between sums and their constituents is not bijective.
$endgroup$
– Sjoerd C. de Vries
13 hours ago




$begingroup$
How do you think one could infer the individual counts from a total count? Once we have totaled data and thrown away the parts there is no way to reconstruct them. The mapping between sums and their constituents is not bijective.
$endgroup$
– Sjoerd C. de Vries
13 hours ago










2 Answers
2






active

oldest

votes


















6












$begingroup$

The reshaping can be done in several ways. Below is given one using SparseArray.



First generating the data (simpler than in the question):



datafunction = MultinormalDistribution[{0, 0}, {{2, 1/2}, {1/2, 1}}];

data1 = N[Table[PDF[datafunction][{x, y}], {x, -4, 4, 1}, {y, -2, 2, 1}]];

MatrixForm[data1]


Make index-to-value associations corresponding to the ranges used to make data1:



aX = AssociationThread[Range[Length[#]], #] &@Range[-4, 4, 1];
aY = AssociationThread[Range[Length[#]], #] &@Range[-2, 2, 1];


Convert to a sparse array, take the corresponding rules, and map the {x,y} indexes to the actual x's and y's.



arules = Most[ArrayRules[SparseArray[data1]]];
data2 = Map[{aX[#[[1, 1]]], aY[#[[1, 2]]], #[[2]]} &, arules]


Plot (note the axes ticks):



ListContourPlot[data2]


enter image description here






share|improve this answer









$endgroup$





















    4












    $begingroup$

    An alternative approach based on Rescaleing the "NonzeroPositions" of SparseArray[data1]:



    xrange = {-4, 4};
    yrange = {-2, 2};
    sa = SparseArray[data1];
    nzp = sa["NonzeroPositions"];
    nzv = sa["NonzeroValues"];
    data2b = Join[Transpose[Rescale[#, MinMax@#, #2] & @@@
    Thread[ {Transpose@nzp, {xrange, yrange}}]], List /@ nzv, 2];

    data2b == data2 (* from Anton's answer *)



    True







    share|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: "387"
      };
      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: false,
      noModals: true,
      showLowRepImageUploadWarning: true,
      reputationToPostImages: null,
      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
      },
      onDemand: true,
      discardSelector: ".discard-answer"
      ,immediatelyShowMarkdownHelp:true
      });


      }
      });














      draft saved

      draft discarded


















      StackExchange.ready(
      function () {
      StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fmathematica.stackexchange.com%2fquestions%2f192942%2fconverting-from-matrix-data-into-coordinate-data%23new-answer', 'question_page');
      }
      );

      Post as a guest















      Required, but never shown

























      2 Answers
      2






      active

      oldest

      votes








      2 Answers
      2






      active

      oldest

      votes









      active

      oldest

      votes






      active

      oldest

      votes









      6












      $begingroup$

      The reshaping can be done in several ways. Below is given one using SparseArray.



      First generating the data (simpler than in the question):



      datafunction = MultinormalDistribution[{0, 0}, {{2, 1/2}, {1/2, 1}}];

      data1 = N[Table[PDF[datafunction][{x, y}], {x, -4, 4, 1}, {y, -2, 2, 1}]];

      MatrixForm[data1]


      Make index-to-value associations corresponding to the ranges used to make data1:



      aX = AssociationThread[Range[Length[#]], #] &@Range[-4, 4, 1];
      aY = AssociationThread[Range[Length[#]], #] &@Range[-2, 2, 1];


      Convert to a sparse array, take the corresponding rules, and map the {x,y} indexes to the actual x's and y's.



      arules = Most[ArrayRules[SparseArray[data1]]];
      data2 = Map[{aX[#[[1, 1]]], aY[#[[1, 2]]], #[[2]]} &, arules]


      Plot (note the axes ticks):



      ListContourPlot[data2]


      enter image description here






      share|improve this answer









      $endgroup$


















        6












        $begingroup$

        The reshaping can be done in several ways. Below is given one using SparseArray.



        First generating the data (simpler than in the question):



        datafunction = MultinormalDistribution[{0, 0}, {{2, 1/2}, {1/2, 1}}];

        data1 = N[Table[PDF[datafunction][{x, y}], {x, -4, 4, 1}, {y, -2, 2, 1}]];

        MatrixForm[data1]


        Make index-to-value associations corresponding to the ranges used to make data1:



        aX = AssociationThread[Range[Length[#]], #] &@Range[-4, 4, 1];
        aY = AssociationThread[Range[Length[#]], #] &@Range[-2, 2, 1];


        Convert to a sparse array, take the corresponding rules, and map the {x,y} indexes to the actual x's and y's.



        arules = Most[ArrayRules[SparseArray[data1]]];
        data2 = Map[{aX[#[[1, 1]]], aY[#[[1, 2]]], #[[2]]} &, arules]


        Plot (note the axes ticks):



        ListContourPlot[data2]


        enter image description here






        share|improve this answer









        $endgroup$
















          6












          6








          6





          $begingroup$

          The reshaping can be done in several ways. Below is given one using SparseArray.



          First generating the data (simpler than in the question):



          datafunction = MultinormalDistribution[{0, 0}, {{2, 1/2}, {1/2, 1}}];

          data1 = N[Table[PDF[datafunction][{x, y}], {x, -4, 4, 1}, {y, -2, 2, 1}]];

          MatrixForm[data1]


          Make index-to-value associations corresponding to the ranges used to make data1:



          aX = AssociationThread[Range[Length[#]], #] &@Range[-4, 4, 1];
          aY = AssociationThread[Range[Length[#]], #] &@Range[-2, 2, 1];


          Convert to a sparse array, take the corresponding rules, and map the {x,y} indexes to the actual x's and y's.



          arules = Most[ArrayRules[SparseArray[data1]]];
          data2 = Map[{aX[#[[1, 1]]], aY[#[[1, 2]]], #[[2]]} &, arules]


          Plot (note the axes ticks):



          ListContourPlot[data2]


          enter image description here






          share|improve this answer









          $endgroup$



          The reshaping can be done in several ways. Below is given one using SparseArray.



          First generating the data (simpler than in the question):



          datafunction = MultinormalDistribution[{0, 0}, {{2, 1/2}, {1/2, 1}}];

          data1 = N[Table[PDF[datafunction][{x, y}], {x, -4, 4, 1}, {y, -2, 2, 1}]];

          MatrixForm[data1]


          Make index-to-value associations corresponding to the ranges used to make data1:



          aX = AssociationThread[Range[Length[#]], #] &@Range[-4, 4, 1];
          aY = AssociationThread[Range[Length[#]], #] &@Range[-2, 2, 1];


          Convert to a sparse array, take the corresponding rules, and map the {x,y} indexes to the actual x's and y's.



          arules = Most[ArrayRules[SparseArray[data1]]];
          data2 = Map[{aX[#[[1, 1]]], aY[#[[1, 2]]], #[[2]]} &, arules]


          Plot (note the axes ticks):



          ListContourPlot[data2]


          enter image description here







          share|improve this answer












          share|improve this answer



          share|improve this answer










          answered 11 hours ago









          Anton AntonovAnton Antonov

          24k167114




          24k167114























              4












              $begingroup$

              An alternative approach based on Rescaleing the "NonzeroPositions" of SparseArray[data1]:



              xrange = {-4, 4};
              yrange = {-2, 2};
              sa = SparseArray[data1];
              nzp = sa["NonzeroPositions"];
              nzv = sa["NonzeroValues"];
              data2b = Join[Transpose[Rescale[#, MinMax@#, #2] & @@@
              Thread[ {Transpose@nzp, {xrange, yrange}}]], List /@ nzv, 2];

              data2b == data2 (* from Anton's answer *)



              True







              share|improve this answer









              $endgroup$


















                4












                $begingroup$

                An alternative approach based on Rescaleing the "NonzeroPositions" of SparseArray[data1]:



                xrange = {-4, 4};
                yrange = {-2, 2};
                sa = SparseArray[data1];
                nzp = sa["NonzeroPositions"];
                nzv = sa["NonzeroValues"];
                data2b = Join[Transpose[Rescale[#, MinMax@#, #2] & @@@
                Thread[ {Transpose@nzp, {xrange, yrange}}]], List /@ nzv, 2];

                data2b == data2 (* from Anton's answer *)



                True







                share|improve this answer









                $endgroup$
















                  4












                  4








                  4





                  $begingroup$

                  An alternative approach based on Rescaleing the "NonzeroPositions" of SparseArray[data1]:



                  xrange = {-4, 4};
                  yrange = {-2, 2};
                  sa = SparseArray[data1];
                  nzp = sa["NonzeroPositions"];
                  nzv = sa["NonzeroValues"];
                  data2b = Join[Transpose[Rescale[#, MinMax@#, #2] & @@@
                  Thread[ {Transpose@nzp, {xrange, yrange}}]], List /@ nzv, 2];

                  data2b == data2 (* from Anton's answer *)



                  True







                  share|improve this answer









                  $endgroup$



                  An alternative approach based on Rescaleing the "NonzeroPositions" of SparseArray[data1]:



                  xrange = {-4, 4};
                  yrange = {-2, 2};
                  sa = SparseArray[data1];
                  nzp = sa["NonzeroPositions"];
                  nzv = sa["NonzeroValues"];
                  data2b = Join[Transpose[Rescale[#, MinMax@#, #2] & @@@
                  Thread[ {Transpose@nzp, {xrange, yrange}}]], List /@ nzv, 2];

                  data2b == data2 (* from Anton's answer *)



                  True








                  share|improve this answer












                  share|improve this answer



                  share|improve this answer










                  answered 4 hours ago









                  kglrkglr

                  188k10203421




                  188k10203421






























                      draft saved

                      draft discarded




















































                      Thanks for contributing an answer to Mathematica 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%2fmathematica.stackexchange.com%2fquestions%2f192942%2fconverting-from-matrix-data-into-coordinate-data%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

                      "Incorrect syntax near the keyword 'ON'. (on update cascade, on delete cascade,)

                      Alcedinidae

                      RAC Tourist Trophy