Wolfram Language Paclet Repository
Community-contributed installable additions to the Wolfram Language
Wolfram`TensorNetworks`
TensorNetworkIndexDimensions  |
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Examples
(5)
Scope
(3)
Duplicates for shared indices
(1)
Each index appears once per occurrence; does not deduplicate, so a shared label appears as many times as the number of tensors containing it.
In[1]:=
SeedRandom[1];tn=
[{RandomReal[{-1,1},{2,3}],RandomReal[{-1,1},{3,4}]},{{i,j},{j,k}}];
 | TensorNetwork |
In[2]:=
 | TensorNetworkIndexDimensions |
Out[2]=
{i2,j3,j3,k4}
Wrap with to collapse duplicates into a unique-key lookup table; later rules overwrite earlier ones with the same key, which is safe here because the dimensions agree:
…
In[3]:=
[tn]
 | TensorNetworkIndexDimensions |
Out[3]=
i2,j3,k4
In[4]:=
GroupBy
[tn],First
| TensorNetworkIndexDimensions |
Out[4]=
i{i2},j{j3,j3},k{k4}
Graph form
(1)
Property form
(1)
Applications
(1)
Properties & Relations
(1)
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Get the dimension of each index occurrence in a tensor network:
In[1]:=
tn=
[{RandomReal[{-1,1},{2,3}],RandomReal[{-1,1},{3,4}]},{{1,2},{2,3}}];
| TensorNetwork |
In[2]:=
| TensorNetworkIndexDimensions |
Out[2]=
{12,23,23,34}
The shared index appears in both tensors, so it contributes two rules with the same right-hand side. The free indices and contribute one rule each.
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1
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The same dimensions show up for a structured network such as a 4-site matrix product state:
In[3]:=
SeedRandom[42];
["MPS"[4,2,2]]
| TensorNetworkIndexDimensions |
| RandomTensorNetwork |
Out[3]=
{12,52,12,22,62,22,32,72,32,82}
Every bond index (, , ) appears twice; every physical index (, , , ) appears once. The right-hand sides agree across occurrences of the same index.
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The low-level form takes explicit per-tensor indices and dimensions directly, with no TensorNetwork object involved:
In[4]:=
| TensorNetworkIndexDimensions |
Out[4]=
{13,24}
The two-argument form is equivalent and takes the dimensions from the tensor list directly:
In[5]:=
| TensorNetworkIndexDimensions |
Out[5]=
{12,23,23,34}
""