Huaiyu Zhu <huaiyu_zhu@[...].com>  writes:

>  Two related questions:
>  
>  1. Suppose  B = ravel(A) and
>              B[i] corresponds to A[i0,i1,...].
>  
>     Are there named functions that map the indices
>  
>          (i0,i0,...) -> i
>  
>     and back?  This is assuming A.shape = (m0,m1,...) is known.

Untested, but the idea should work:

  def ravel_index(array, *indices):
     offsets = Numeric.multiply.accumulate(array.shape[1:][::-1])[::-1]
     return Numeric.sum(Numeric.array(indices[:-1])*offsets) + indices[-1]

>  2. Suppose the above function is called ravel_index and its
>     inverse unravel_index.
>  
>     Given a list of matrices [A0, A1, ...] is there a function that
>     calculates a matrix B such that
>  
>          B[i,j]  = A0[i0,j] * A1[i1,j] * ...
>  
>     where i = ravel_index(i0, i1, ...).

Not for all i, which I assume is what you want to do.

Konrad.
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