[AutoDiff] Registers VJPs for FloatingPoint.[maximum|minimum]
#35379
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Resolves TF-1134.
vguerra
commented
Jan 12, 2021
| static func _vjpMinimum(_ x: Self, _ y: Self) -> ( | ||
| value: Self, pullback: (TangentVector) -> (TangentVector, TangentVector) | ||
| ) { | ||
| func pullback(_ v: TangentVector) -> (TangentVector, TangentVector) { |
There was a problem hiding this comment.
This pullback is defined according to the logic of FloatingPoint.minimum so that the corner cases for returning either x or y are respected.
There was a problem hiding this comment.
This implementation is running the identical control flow in the VJP and the pullback. It should be simplified so that the pullback is just straight line code and the control flow is executed only once. You can do:
@inlinable
@derivative(of: minimum)
static func _vjpMinimum(_ x: Self, _ y: Self) -> (
value: Self, pullback: (TangentVector) -> (TangentVector, TangentVector)
) {
if x <= y || y.isNaN { return (x, { v in (v, .zero) }) }
return (y, { v in (.zero, v) })
}The same suggestion applies to maximum.
There was a problem hiding this comment.
Ah I see.. yes, thanks for the remark @rxwei .. i am fixing that.
vguerra
commented
Jan 12, 2021
| static func _vjpMaximum(_ x: Self, _ y: Self) -> ( | ||
| value: Self, pullback: (TangentVector) -> (TangentVector, TangentVector) | ||
| ) { | ||
| func pullback(_ v: TangentVector) -> (TangentVector, TangentVector) { |
There was a problem hiding this comment.
same comment as above but for FloatingPoint.maximum.
dan-zheng
approved these changes
Jan 12, 2021
|
@swift-ci Please test |
To avoid executing control flow code twice ( once in VJP and once in the pullback ).
|
@swift-ci please test |
rxwei
approved these changes
Jan 13, 2021
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Resolves TF-1134.