# \#manifolds

**URL:** https://discourse.julialang.org/tag/manifolds/1288.md

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## [Tangent/Cotangent bundles in Manifolds.jl](https://discourse.julialang.org/t/tangent-cotangent-bundles-in-manifolds-jl/137801)

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**Author:** [@SteffenPL](https://discourse.julialang.org/u/SteffenPL)\
**Replies:** 13\
**Last updated:** [September 23, 2026, 10:45am UTC](https://discourse.julialang.org/t/tangent-cotangent-bundles-in-manifolds-jl/137801 "2026-09-23T10:45:23Z")

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What would be the canonical way to represent a cotangent vector with Manifolds.jl? As far as I can see, there is no space for T \\mathcal{M} or T^\* \\mathcal{M}, hence the canonical representation would be a tuple (pt, vec…

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## [\[ANN\] Manopt.jl](https://discourse.julialang.org/t/ann-manopt-jl/24906)

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**Author:** [@kellertuer](https://discourse.julialang.org/u/kellertuer)\
**Replies:** 56\
**Last updated:** [August 21, 2026, 1:52pm UTC](https://discourse.julialang.org/t/ann-manopt-jl/24906 "2026-08-21T13:52:13Z")

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Manopt.jl provides a framework for optimization on manifolds. Based on Manopt and MVIRT, both implemented in Matlab, this toolbox provide an easy access to optimization methods on manifolds in Julia. If you want to del…

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## [Optim.jl : user defined Manifold, error in the definition of the retraction](https://discourse.julialang.org/t/optim-jl-user-defined-manifold-error-in-the-definition-of-the-retraction/130297)

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**Author:** [@aitzkora](https://discourse.julialang.org/u/aitzkora)\
**Replies:** 2\
**Last updated:** [June 29, 2025, 8:49pm UTC](https://discourse.julialang.org/t/optim-jl-user-defined-manifold-error-in-the-definition-of-the-retraction/130297 "2025-06-29T20:49:42Z")

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Hi, I try to optimize a simple quadratic function on a user-defined manifold (the hyperplan orthogonal to ones(n)) with the following code using Optim const c = ones(2) ./ sqrt(2) f(x) = 0.5 \* sum((x - c).^2) g!(g,x) =…

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## [Need help on Manopt](https://discourse.julialang.org/t/need-help-on-manopt/100867)

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**Author:** [@dgagnon](https://discourse.julialang.org/u/dgagnon)\
**Replies:** 13\
**Last updated:** [June 30, 2023, 12:08pm UTC](https://discourse.julialang.org/t/need-help-on-manopt/100867 "2023-06-30T12:08:27Z")

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Hello I must find a maximum likelihood estimator for a distribution I have designed. But, I can’t have an explicit expression for it. Looking at another thread: Maximum likelihood for t-distribution by gradient descent,…

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## [\[ANN\] ManoptExamples.jl – Optimization Tasks on Manifolds](https://discourse.julialang.org/t/ann-manoptexamples-jl-optimization-tasks-on-manifolds/95001)

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**Author:** [@kellertuer](https://discourse.julialang.org/u/kellertuer)\
**Replies:** 0\
**Last updated:** [February 22, 2023, 8:13am UTC](https://discourse.julialang.org/t/ann-manoptexamples-jl-optimization-tasks-on-manifolds/95001 "2023-02-22T08:13:10Z")

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With both Manifolds.jl and Manopt.jl being relatively stable by now, we decided to start a package that focuses on providing easy access to example problems. ManoptExamples.jl is a (for now early stage, young) package t…