v0.3.18

ITensors v0.3.18

Diff since v0.3.17

Closed issues:

• [ITensors] [BUG] OpSum subtraction error (#932)
• [ITensors] [BUG] - of MPOs is not differentiable (#934)
• [ITensors] [BUG] exp(loginner()) not equivalent to inner() (#944)
• [ITensors] [BUG] Mistake in the Documentation of Custom Observer (#947)

Merged pull requests:

• [ITensors] [ENHANCEMENT] Fix directsum when specifying a single Index (#930) (@mtfishman)
• [ITensors] [ENHANCEMENT] Add rrules for addition and subtraction of MPOs (#935) (@hjkqubit)
• [ITensors] [BUG] Fix bug in loginner when inner is negative or complex (#945) (@mtfishman)
• [ITensors] [ENHANCMENT] rrule for MPO constructor by generalizing the rrule for the MPS constructor (#946) (@hjkqubit)
• [WIP] [ITensors] [ENHANCEMENT] Fix apply(::MPO, ::MPO) autodiff (#949) (@mtfishman)