v0.4.2

PEPSKit v0.4.2

Diff since v0.4.1

Merged pull requests:

• Add eigsolve-style rrule for CTMRG fixed-point gradient (#126) (@leburgel)
• Clean up and simplify optimization interface (#127) (@pbrehmer)
• Add bond truncation algorithms for time evolution (#128) (@Yue-Zhengyuan)
• Implement keyword selector (#130) (@pbrehmer)
• Add unified contractible network interface (#131) (@leburgel)
• Refactor boundary MPS contractions (#132) (@leburgel)
• Enforce FixedSpaceTruncation during differentiation (#140) (@pbrehmer)
• Pick out CTMRG left move as a separate function (#141) (@Yue-Zhengyuan)
• Wrap SU intermediate steps into functions (#143) (@Yue-Zhengyuan)
• Refactor absorb_weight and use leftorth in _qr_bond (#146) (@Yue-Zhengyuan)
• Fix Base.similar for physical and contractible network types (#149) (@leburgel)
• Bump KrylovKit compat (#156) (@leburgel)

Closed issues:

• Use FixedSpaceTruncation in CTMRG rrule (#138)