[SciPy-User] [SciPy-user] ValueError: arrays must have same number of dimensions

Jorge E. ´Sanchez Sanchez hnry2k@hotmail....
Thu Jun 28 11:31:09 CDT 2012


Look at Tony Yu's nice translation, it should work

Regards
Jorge

> Date: Thu, 28 Jun 2012 09:25:48 -0700
> From: surfcast23@gmail.com
> To: scipy-user@scipy.org
> Subject: Re: [SciPy-User] [SciPy-user] ValueError: arrays must have same number of dimensions
> 
> 
> Hi Jorgre,
> 
>   I totally forgot the fact that python loops go to N-1 thanks. I am now
> getting this for the array shapes
> 
> v.shape (512,)
> k.shape (100, 512)
> 
> and still the error 
> 
> data = np.concatenate((v, k),axis = 0);
> ValueError: arrays must have same number of dimensions
> 
> 
> do I need to some how make the first dimension of k 512?
> 
> 
> Jorge E. ´Sanchez Sanchez wrote:
> > 
> > 
> > Hi,
> > 
> > it seems to me that you don't know that loops in python end before the
> > last index value of the loop,
> > you just need to do something like:
> >  Np1 = N+1
> > for j in range (1, Np1):
> > 
> > HTH
> > Best Regards
> > Jorge
> > 
> > 
> >> Date: Thu, 28 Jun 2012 08:32:47 -0700
> >> From: surfcast23@gmail.com
> >> To: scipy-user@scipy.org
> >> Subject: [SciPy-User] [SciPy-user] ValueError: arrays must have same
> >> number	of dimensions
> >> 
> >> 
> >> Hi I am trying to translate a Matlab code from Trefethen's Spectral
> >> Methods
> >> in MATLAB to Python. I am running into a problem with numpy.concatenate
> >> wanting the arrays to have the same number of dimensions.
> >> Here is part of the Matlab code that I am rewriting 
> >> 
> >> 
> >> N = 512; h = 2*pi/N; x = h*(1:N); t = 0; dt = h/4;
> >> a = .1;
> >> c = a + sin (x-1).^2;
> >> v = exp(-100*(x-1).^2); vold = exp(-100*(x-a*dt-1).^2);
> >> 
> >> column = [0 .5*(-1).^(1:N-1).*cot((1:N-1)*h/2)];
> >> D = toeplitz(column,-column);
> >> 
> >> % Time-stepping by leap frog formula:
> >> tmax = 15; tplot = .15; clf, drawnow, set(gcf,'renderer','zbuffer')
> >> plotgap = round(tplot/dt); dt = tplot/plotgap;
> >> nplots = round(tmax/tplot);
> >> data = [v; zeros(nplots,N)]; tdata = t;
> >> 
> >> 
> >> What I am trying in Python
> >> 
> >> for j in range(1,N):
> >>  tmax = 15;   
> >>  tplot = .15;
> >>  h = 2*pi/N;
> >>  dt = h/4; 
> >>  nplots = around(tmax/tplot);
> >>  plotgap = around(tplot/dt);
> >>  dt = tplot/plotgap;  
> >>  x = h*arange(1,N);
> >>  c = a+np.sin(x-1)**2;
> >>  v = exp(-100*(x-1)**2);
> >>  vold = exp(-100*(x-a*dt-1)**2);
> >>  
> >>  column = ((0.5*(-1)**arange(1,N-1))*cotdg(arange(1,N-1))*(h/2));
> >>  D = toeplitz(column,-column);
> >>  
> >>  k = np.zeros(((nplots,N)));
> >>  data = np.concatenate((v, k),axis = 0);
> >>  tdata = t;
> >> 
> >> 
> >> I have highlighted the vectors in question.
> >> v.shape gives (511,)
> >> 
> >> k.shape gives (100, 512)
> >> 
> >> I would appreciate any help with this. Thank you!
> >> 
> >> -- 
> >> View this message in context:
> >> http://old.nabble.com/ValueError%3A-arrays-must-have-same-number-of-dimensions-tp34086886p34086886.html
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> >> 
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> 
> -- 
> View this message in context: http://old.nabble.com/ValueError%3A-arrays-must-have-same-number-of-dimensions-tp34086886p34087175.html
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