[Numpy-discussion] dot function or dot notation, matrices, arrays?

Wayne Watson sierra_mtnview@sbcglobal....
Fri Dec 18 23:22:02 CST 2009


Nicely done.

Alan G Isaac wrote:
> On 12/18/2009 7:12 PM, Wayne Watson wrote:
>   
>> The point of the scalar product is to produce theta.
>>     
>
> As David said, that is just NumPy's `dot`.
>
>   
>>>> a = np.array([0,2])
>>>> b = np.array([5,0])
>>>> theta = np.arccos(np.dot(a,b)/np.sqrt(np.dot(a,a)*np.dot(b,b)))
>>>> theta
>>>>         
> 1.5707963267948966
>   
>>>> theta/np.pi
>>>>         
> 0.5
>
> hth,
> Alan Isaac
>
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>   

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           Wayne Watson (Watson Adventures, Prop., Nevada City, CA)

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