Essential functions TODO list.

[hzhangxyz]

• arithmetic (Add the basic parity tensor class and its arithmetic operators. #2) (Check type error in arithmetic operators. #9) (Add check for type error for inplace arithmetic operators. #54)
• masking (Add tensor mask for parity tensor. #10) (Add field parity, and copy parity and mask in arithmetic operators. #11)
• permute (Add support to permute a tensor. #12) (Fix bug in permute function and fix a type. #28)
• reverse (Add support for reverse. #29)
• split edge (Add reshape function. #39) (Add support for trivial edges in reshape function #64) (Fix issue when reshape with none edge. #67) (Fix corner cases in reshape and improve its robustness #72)
• merge edge (Add reshape function. #39) (Add support for trivial edges in reshape function #64) (Fix issue when reshape with none edge. #67) (Fix corner cases in reshape and improve its robustness #72)
• contract (Add support for matmul. #59) (Fix svd arrow #79) (Refactor contract api #82)
• trace (dev/add support for trace #68)
• conjugate (Add support for conjugate #81)
• svd (Add support for svd #70)
• qr
• identity (Add support for identity #77)
• exponential (Add support for exponential #75) (Add support for identity #77)

See: https://github.com/USTC-TNS/TNSP/blob/v0.4/tat/tensor.py