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

surfcast23 surfcast23@gmail....
Thu Jun 28 11:25:48 CDT 2012


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
>> Sent from the Scipy-User mailing list archive at Nabble.com.
>> 
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