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July 2010

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172 discussions

Meshgrid and mgrid Differences
by Jed Ludlow July 15, 2010

July 15, 2010

Hello, all. Is there a technical reason that 'meshgrid' and 'mgrid' produce results which differ from each other by a transpose? For example, In [1]: X,Y = meshgrid(array([0,1,2,3]), array([0,1,2,3,4,5])) In [2]: X Out[2]: array([[0, 1, 2, 3], [0, 1, 2, 3], [0, 1, 2, 3], [0, 1, 2, 3], [0, 1, 2, 3], [0, 1, 2, 3]]) In [3]: Y Out[3]: array([[0, 0, 0, 0], [1, 1, 1, 1], [2, 2, 2, 2], [3, 3, 3, 3], [4, 4, 4, 4], [5, 5, 5, 5]]) In [4]: U,V = mgrid[0:4,0:6] In [5]: U Out[5]: array([[0, 0, 0, 0, 0, 0], [1, 1, 1, 1, 1, 1], [2, 2, 2, 2, 2, 2], [3, 3, 3, 3, 3, 3]]) In [6]: V Out[6]: array([[0, 1, 2, 3, 4, 5], [0, 1, 2, 3, 4, 5], [0, 1, 2, 3, 4, 5], [0, 1, 2, 3, 4, 5]]) The functions seemed to be designed to do a similar task. It may not seem like a major difference, but it does make for interesting downstream effects, particularly when working with mayavi.mlab. When you call mlab.surf(s) it gets the axes sense correct only if you used mgrid to generate the x-y grid for evaluating s. If you used meshgrid to generate the x-y grid the surface gets rotated in the scene by 90 degrees. Regards, Jed Ludlow

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Re: [Numpy-discussion] Array concatenation performance
by jf＠heliotis.ch July 15, 2010

July 15, 2010

I will be out of office till 8. August For urgent matters, please contact Patrick.Lambelet(a)heliotis.ch

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Re: [Numpy-discussion] Array concatenation performance
by jf＠heliotis.ch July 15, 2010

July 15, 2010

I will be out of office till 8. August For urgent matters, please contact Patrick.Lambelet(a)heliotis.ch

1 0

Re: [Numpy-discussion] Array concatenation performance
by jf＠heliotis.ch July 15, 2010

July 15, 2010

I will be out of office till 8. August For urgent matters, please contact Patrick.Lambelet(a)heliotis.ch

1 0

Re: [Numpy-discussion] Array concatenation performance
by jf＠heliotis.ch July 15, 2010

July 15, 2010

I will be out of office till 8. August For urgent matters, please contact Patrick.Lambelet(a)heliotis.ch

1 0

Re: [Numpy-discussion] Array concatenation performance
by jf＠heliotis.ch July 15, 2010

July 15, 2010

I will be out of office till 8. August For urgent matters, please contact Patrick.Lambelet(a)heliotis.ch

1 0

Re: [Numpy-discussion] Array concatenation performance
by jf＠heliotis.ch July 15, 2010

July 15, 2010

I will be out of office till 8. August For urgent matters, please contact Patrick.Lambelet(a)heliotis.ch

1 0

Re: [Numpy-discussion] Array concatenation performance
by jf＠heliotis.ch July 15, 2010

July 15, 2010

I will be out of office till 8. August For urgent matters, please contact Patrick.Lambelet(a)heliotis.ch

1 0

Re: [Numpy-discussion] Array concatenation performance
by jf＠heliotis.ch July 15, 2010

July 15, 2010

I will be out of office till 8. August For urgent matters, please contact Patrick.Lambelet(a)heliotis.ch

1 0

Re: [Numpy-discussion] Array concatenation performance
by jf＠heliotis.ch July 15, 2010

July 15, 2010

I will be out of office till 8. August For urgent matters, please contact Patrick.Lambelet(a)heliotis.ch

1 0

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