Square array from linear array python





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I would like to get a square matrix B from a linear vector A such that B = A * transpose(A). A is a numpy array and np.shape(A) returns (10,). I would like B to be a (10,10) array. I tried B = np.matmut(A, A[np.newaxis]) but I get an error :




shapes (10,) and (1,10) not aligned: 10 (dim 0) != 1 (dim 0)










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  • What I want is the equivalent of "B=A*ctranspose(A)" in matlab

    – Mathieu Lecoq
    Nov 23 '18 at 14:12


















1















I would like to get a square matrix B from a linear vector A such that B = A * transpose(A). A is a numpy array and np.shape(A) returns (10,). I would like B to be a (10,10) array. I tried B = np.matmut(A, A[np.newaxis]) but I get an error :




shapes (10,) and (1,10) not aligned: 10 (dim 0) != 1 (dim 0)










share|improve this question

























  • What I want is the equivalent of "B=A*ctranspose(A)" in matlab

    – Mathieu Lecoq
    Nov 23 '18 at 14:12














1












1








1








I would like to get a square matrix B from a linear vector A such that B = A * transpose(A). A is a numpy array and np.shape(A) returns (10,). I would like B to be a (10,10) array. I tried B = np.matmut(A, A[np.newaxis]) but I get an error :




shapes (10,) and (1,10) not aligned: 10 (dim 0) != 1 (dim 0)










share|improve this question
















I would like to get a square matrix B from a linear vector A such that B = A * transpose(A). A is a numpy array and np.shape(A) returns (10,). I would like B to be a (10,10) array. I tried B = np.matmut(A, A[np.newaxis]) but I get an error :




shapes (10,) and (1,10) not aligned: 10 (dim 0) != 1 (dim 0)







python arrays numpy matrix vector






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share|improve this question













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edited Nov 23 '18 at 19:16









MarianD

4,46761432




4,46761432










asked Nov 23 '18 at 14:08









Mathieu LecoqMathieu Lecoq

83




83













  • What I want is the equivalent of "B=A*ctranspose(A)" in matlab

    – Mathieu Lecoq
    Nov 23 '18 at 14:12



















  • What I want is the equivalent of "B=A*ctranspose(A)" in matlab

    – Mathieu Lecoq
    Nov 23 '18 at 14:12

















What I want is the equivalent of "B=A*ctranspose(A)" in matlab

– Mathieu Lecoq
Nov 23 '18 at 14:12





What I want is the equivalent of "B=A*ctranspose(A)" in matlab

– Mathieu Lecoq
Nov 23 '18 at 14:12












3 Answers
3






active

oldest

votes


















3














you can do this using outer:



import numpy as np
vector = np.arange(10)
np.outer(vector, vector)





share|improve this answer































    2














    The solution is a little ugly, but it does what you need.



    import numpy as np

    vector = np.array([1,2,3,4,5,6,7,8,9,10],)
    matrix = np.dot(vector[:,None],vector[None,:])
    print(matrix)


    You can also do the following:



    import numpy as np

    vector = np.array([1,2,3,4,5,6,7,8,9,10],)
    matrix = vector*vector[:,None]
    print(matrix)


    The issue comes from the fact that transposing a one dimensional array does not have the effect you might expect.






    share|improve this answer































      0














      Variation on outer product:



      a = A.reshape(-1, 1) # make sure it's a column vector
      B = a @ a.T





      share|improve this answer
























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        3 Answers
        3






        active

        oldest

        votes








        3 Answers
        3






        active

        oldest

        votes









        active

        oldest

        votes






        active

        oldest

        votes









        3














        you can do this using outer:



        import numpy as np
        vector = np.arange(10)
        np.outer(vector, vector)





        share|improve this answer




























          3














          you can do this using outer:



          import numpy as np
          vector = np.arange(10)
          np.outer(vector, vector)





          share|improve this answer


























            3












            3








            3







            you can do this using outer:



            import numpy as np
            vector = np.arange(10)
            np.outer(vector, vector)





            share|improve this answer













            you can do this using outer:



            import numpy as np
            vector = np.arange(10)
            np.outer(vector, vector)






            share|improve this answer












            share|improve this answer



            share|improve this answer










            answered Nov 23 '18 at 14:20









            jeremycgjeremycg

            19.1k44257




            19.1k44257

























                2














                The solution is a little ugly, but it does what you need.



                import numpy as np

                vector = np.array([1,2,3,4,5,6,7,8,9,10],)
                matrix = np.dot(vector[:,None],vector[None,:])
                print(matrix)


                You can also do the following:



                import numpy as np

                vector = np.array([1,2,3,4,5,6,7,8,9,10],)
                matrix = vector*vector[:,None]
                print(matrix)


                The issue comes from the fact that transposing a one dimensional array does not have the effect you might expect.






                share|improve this answer




























                  2














                  The solution is a little ugly, but it does what you need.



                  import numpy as np

                  vector = np.array([1,2,3,4,5,6,7,8,9,10],)
                  matrix = np.dot(vector[:,None],vector[None,:])
                  print(matrix)


                  You can also do the following:



                  import numpy as np

                  vector = np.array([1,2,3,4,5,6,7,8,9,10],)
                  matrix = vector*vector[:,None]
                  print(matrix)


                  The issue comes from the fact that transposing a one dimensional array does not have the effect you might expect.






                  share|improve this answer


























                    2












                    2








                    2







                    The solution is a little ugly, but it does what you need.



                    import numpy as np

                    vector = np.array([1,2,3,4,5,6,7,8,9,10],)
                    matrix = np.dot(vector[:,None],vector[None,:])
                    print(matrix)


                    You can also do the following:



                    import numpy as np

                    vector = np.array([1,2,3,4,5,6,7,8,9,10],)
                    matrix = vector*vector[:,None]
                    print(matrix)


                    The issue comes from the fact that transposing a one dimensional array does not have the effect you might expect.






                    share|improve this answer













                    The solution is a little ugly, but it does what you need.



                    import numpy as np

                    vector = np.array([1,2,3,4,5,6,7,8,9,10],)
                    matrix = np.dot(vector[:,None],vector[None,:])
                    print(matrix)


                    You can also do the following:



                    import numpy as np

                    vector = np.array([1,2,3,4,5,6,7,8,9,10],)
                    matrix = vector*vector[:,None]
                    print(matrix)


                    The issue comes from the fact that transposing a one dimensional array does not have the effect you might expect.







                    share|improve this answer












                    share|improve this answer



                    share|improve this answer










                    answered Nov 23 '18 at 14:19









                    Esteban QuirosEsteban Quiros

                    1015




                    1015























                        0














                        Variation on outer product:



                        a = A.reshape(-1, 1) # make sure it's a column vector
                        B = a @ a.T





                        share|improve this answer




























                          0














                          Variation on outer product:



                          a = A.reshape(-1, 1) # make sure it's a column vector
                          B = a @ a.T





                          share|improve this answer


























                            0












                            0








                            0







                            Variation on outer product:



                            a = A.reshape(-1, 1) # make sure it's a column vector
                            B = a @ a.T





                            share|improve this answer













                            Variation on outer product:



                            a = A.reshape(-1, 1) # make sure it's a column vector
                            B = a @ a.T






                            share|improve this answer












                            share|improve this answer



                            share|improve this answer










                            answered Nov 23 '18 at 15:32









                            deckarddeckard

                            31527




                            31527






























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