Update user guide

[manuschneider]

The user guide on github has a version 1.0 already. However, it seems to be outdated and needs to be revisited.

The following changes were made to the API were made:

• Contract, Contracts are merged into Contract
• .relabel, .relabels are merged into .relabel
• .relabel_, .relabels_ are merged into .relabel_
• Svd_truncate has an additional optional argument min_blockdim to define a minimum dimension for each block

Also, we should include all parts from the paper where they are not mentioned in detail in the user guide (they can to many parts just be copied).

I would also merge chapters '9. linalg' and '11. linalg extension', such that it is easier to find SVD, QR, eigval.

Finally, the links to the API documentation seem to be broken.

[yingjerkao]

Are we making progress on this?

[manuschneider]

Here is a list on the progress:

• Update introduction to user guide
• Reference to paper
• Add new generators for UniTensor
• replace 'relabels' by 'relabel'
• Contract, Contracts are merged into Contract
• .Save() should be called with a file name that has a file extension explicitly given
• Svd_truncate has an additional optional argument min_blockdim to define a minimum dimension for each block
• Add extended examples from paper to user guide
• Test all code and update output files
• Update Linalg table
• Update installation and advanced installation sections

[manuschneider]

The linalg table is outdated. Many functions were implemented for UniTensors as well.
I suggest the following columns:
| func() | CPU | GPU | func(T) | func(uT) | T.func() | T.func_() | uT.func() | uT.func_() |
and a short description what these mean under the table.

Do the API doc links work? It seems neither the case for the online documentation on gitlab, nor for my local documentation. Can the links be created in a way that they remain working when the API documentation is updated?