* Add the backward support for QR

* Remove unnecessary comments

* Add QR decomposition op

* Change codes to adapt to new svd_helper

* Update linalg.py

Restore the deleted comma

* Restore the deleted line

* Update linalg.py

* Update linalg.py

* Improve the qr code by reviews

* Update QR based on CI results

* Update qr doc, test=document_fix

* Change unsafe and ill-formed codes

* Add paddle.linalg.eig op

* remove comments

* remove comments

* extend batch_size to the origin

* add real times complex functor & destroy the backward complex output bug

* terminate output diff when input real tensors

* correct tiny doc errors

* move functions from eig_helper to svd_helper and remove eig_helper

* remove tensor.Resize

* remove no longer used code

* use existing lapack functions

* reply review comments 21/27

* remove .cu as this op is only executed on CPU

* remove const_cast & add const in argument list for read-only references

* fix sample code error in CI

* remove template typename Tbase and more

* remove eig exposure in paddle.*

* add 'name=None' in eig python implementation

* handle the unittest

* try to solve the unittest

* solve CI coverage

* remove no longer used code

* polish API doc and more

* reply review comments

* polish unittest, commit plan B

* polish unittest

Implement FunctionTraits to support two kinds of elementwise functor and remove some old codes for broadcast. (#35688)

* init matrix_rank op, add matrix_rank CPU code and test

* add GPU kernel, remove svd_eigen.h

* add CPU kernel when tol is tensor

* add cpu and gpu code when tol is tensor

* fix CI-ROCM error

* add matrix_rank API describe, fix PR-CI-Py3 error

* fix PR-CI-Windows error, add matrix_rank API test

* delete useless comments

* fix review

* add my code in svd_helper.h

* update doc commets

* remove spaces

* Add SVD Op and it's GPU and CPU kernel

* Remove CUDAPlace in test_svd_op, make the test available in CPU package

* modfity the file

* fix windows bug/ fix ROCM / fix test timeout

* for pass the CIs

* improve error report

* for code review

* some modification to test_svd_op

* change python code style

* expose the svd interface for document