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Diff — Gradient

Revision #1899 → #3388 · back to history

modifiedGradient (informal)bc18bd92cc37
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note`gradient f x` is the Mathlib definition of the gradient of a scalar-valued differentiable function on a Hilbert space.`gradient f x := (InnerProductSpace.toDual 𝕜 F).symm (fderiv 𝕜 f x)` is Mathlib's gradient of a scalar-valued differentiable function on a Hilbert space.
modifiedDirection of fastest increase6ba656b983d8
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noteNo `steepest`/`fastest` ascent characterization of the gradient is stated in Mathlib's `Gradient` API.No steepest/fastest-ascent characterization of the gradient is stated in Mathlib's Gradient API.
modifiedStationary point870b9f03f2ce
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noteMathlib has no `IsCritical`/`StationaryPt`/`CriticalPt` definition for zeros of the gradient.Mathlib has no `StationaryPt`/`CriticalPt` definition for zeros of the gradient.
modifiedGradient via partial derivativesb97d9c0f3ff8
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mathlib.match_kindgeneralization
provenanceaiai-moderated
modifiedLinear approximation via gradient8fffc70978fe
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note`hasGradientAt_iff_isLittleO` states `f x' = f x + ⟪f', x' - x⟫ + o(x' - x)`, the gradient linear approximation.`hasGradientAt_iff_isLittleO` states `f x' - f x - ⟪f', x' - x⟫ = o(x' - x)`, the gradient linear-approximation identity.
modifiedGradient is steepest ascent direction996bd94a379e
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noteNo `steepest`/`fastest` ascent theorem about the gradient is present in Mathlib.No steepest/fastest-ascent theorem about the gradient is present in Mathlib.
modifiedGradient on Riemannian manifoldcd2153cd50f3
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noteMathlib's Riemannian-manifold development (`Mathlib.Geometry.Manifold.Riemannian.*`) does not yet contain a gradient definition for smooth scalar functions.Mathlib's Riemannian-manifold development does not yet contain a gradient definition for smooth scalar functions.
addedDirectional derivative (definition used)3474740343de
addedCauchy–Schwarz bound on directional derivative814b544b8836