Problems with high-dimensional lists

*To*: mathgroup at smc.vnet.net*Subject*: [mg2494] Problems with high-dimensional lists*From*: Sascha at sunmail.lrz-muenchen.de, Unzicker at lrz.uni-muenchen.de*Date*: Wed, 15 Nov 1995 01:57:59 -0500*Organization*: Universitaet Muenchen (Germany)

Let me give an example: a=Table[0,{3},{4},{5},{6}]; Dimensions[a] gives you Out[86]= {3, 4, 5, 6}, of course. But if you try to assign a new value to a sublist a[[1,1]]=Table[x,{6},{5}]; Mathematica forgets that a still should have the Dimension {3,4,5,6}: In[88]:= Dimensions[a] Out[88]= {3, 4} In[89]:= Transpose[a,{4,1,2,3}]; Transpose::tperm: Permutation {4, 1, 2, 3} is longer than the dimensions {3, 4} of the array. is now impossible, although In[90]:= a[[3,4,5,6]] Out[90]= 0 returns still the correct value. Why does Mathematica make this difference? If you print a, there is no difference. How can you return to the desired Dimension? a=Array[a,{3,4,5,6}]; is not possible because a[[1,1,1,1]] gives a mess. Thanks in advance, Sascha Unzicker