Skip to content

Added an 'identity' tensor splitting option #241

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
rballester wants to merge 2 commits into
base: main
Choose a base branch
from
Open

Added an 'identity' tensor splitting option #241

Show file tree
Hide file tree
Changes from 1 commit
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
2b4efd7
Added an 'identity' tensor splitting option
rballester Jun 26, 2024
ad30164
PR update
rballester Sep 11, 2024
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
13 changes: 13 additions & 0 deletions quimb/tensor/decomp.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -185,6 +185,19 @@ def _trim_and_renorm_svd_result(
return U, None, VH


@compose
def identity(x, backend=None, **kwargs):
"""
No-op "decomposition" that leaves the input unchanged. Can be useful to quickly build a tensor network representing a given tensor "as is".
"""

with backend_like(backend):
if x.shape[0] < x.shape[1]:
return do("eye", x.shape[0]), do("ones", x.shape[0]), x
else:
return x, do("ones", x.shape[1]), do("eye", x.shape[1])

@jcmgray jcmgray Jul 1, 2024

Copy link
Copy Markdown
Owner

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

The middle element should probably just be left as None, otherwise it flags to calling functions above that 'singular values' have been returned. This happens with other methods only when the option absorb=None. Or one could add that option and but default to absorb=0 (which means absorbed on either side), if you imagine that it might be useful to initialize simple update gauges for example.

I also suggest here using do("eye", x.shape[0], like=x) and do("ones", x.shape[0], like=x) rather than backend_like since autoray now supports picking up the correct device and dtype for these array creation routines.



@compose
def svd_truncated(
x,
Expand Down
1 change: 1 addition & 0 deletions quimb/tensor/tensor_core.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -325,6 +325,7 @@ def rand_uuid(base=""):

_VALID_SPLIT_GET = {None, "arrays", "tensors", "values"}
_SPLIT_FNS = {
"identity": decomp.identity,
"svd": decomp.svd_truncated,
"eig": decomp.svd_via_eig_truncated,
"lu": decomp.lu_truncated,
Expand Down