# Specific Domains

**URL:** https://discourse.julialang.org/c/domain/10.md?no_subcategories=false&page=489

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**Page:** 490

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## [How to edit row values of a dataframe column based on condition using query.jl](https://discourse.julialang.org/t/how-to-edit-row-values-of-a-dataframe-column-based-on-condition-using-query-jl/26437)

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**Author:** [@vivekraj](https://discourse.julialang.org/u/vivekraj)\
**Replies:** 7\
**Last updated:** [July 17, 2019, 6:47pm UTC](https://discourse.julialang.org/t/how-to-edit-row-values-of-a-dataframe-column-based-on-condition-using-query-jl/26437 "2019-07-17T18:47:30Z")

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i have filtered unique values from a column :CarCompany from dataframe: df |\> @map(\_.CarCompany) |\> @unique() |\> collect; the output shows fields with spelling mistakes: 28-element Array{SubString{String},1}: “alfa-r…

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## [How to solve large sparse LPs in Gurobi](https://discourse.julialang.org/t/how-to-solve-large-sparse-lps-in-gurobi/26402)

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**Author:** [@wenqi\_kou](https://discourse.julialang.org/u/wenqi_kou)\
**Replies:** 7\
**Last updated:** [July 17, 2019, 5:20pm UTC](https://discourse.julialang.org/t/how-to-solve-large-sparse-lps-in-gurobi/26402 "2019-07-17T17:20:00Z")

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Hi, I have a question about solving large sparse matrix LP problem. It really confused me for a long time. If I have a form like this: I have all Fi data, which are in sparse form. How can I build a LP model to solv…

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## [AD step for iterative solution](https://discourse.julialang.org/t/ad-step-for-iterative-solution/26404)

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**Author:** [@Tamas\_Papp](https://discourse.julialang.org/u/Tamas_Papp)\
**Replies:** 11\
**Last updated:** [July 17, 2019, 4:09pm UTC](https://discourse.julialang.org/t/ad-step-for-iterative-solution/26404 "2019-07-17T16:09:48Z")

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Sometimes it would be useful to AD through an iterative algorithm, eg solving a parametric problem f(x, a) = 0 which implicitly defines x(a), but in practice uses an iterative rootfinding method. The math is clear (i…

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## [Global constraints in functions](https://discourse.julialang.org/t/global-constraints-in-functions/26341)

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**Author:** [@MuadhF](https://discourse.julialang.org/u/MuadhF)\
**Replies:** 7\
**Last updated:** [July 17, 2019, 6:00am UTC](https://discourse.julialang.org/t/global-constraints-in-functions/26341 "2019-07-17T06:00:24Z")

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Hi, I declared some constraints in a function because I needed an if condition, and wanted to know if I can somehow make these constraints defined outside the function as well. Here’s part of the function: function amo…

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## [Julia's processing capacity](https://discourse.julialang.org/t/julias-processing-capacity/26251)

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**Author:** [@RaquelSantos](https://discourse.julialang.org/u/RaquelSantos)\
**Replies:** 12\
**Last updated:** [July 17, 2019, 4:02am UTC](https://discourse.julialang.org/t/julias-processing-capacity/26251 "2019-07-17T04:02:22Z")

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Julia provides information of type: number of iterations, solution time, gap, number of variables, number of constraints

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## [Parametrize NLsolve function](https://discourse.julialang.org/t/parametrize-nlsolve-function/11886)

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**Author:** [@ufechner7](https://discourse.julialang.org/u/ufechner7)\
**Replies:** 4\
**Last updated:** [July 16, 2019, 10:28pm UTC](https://discourse.julialang.org/t/parametrize-nlsolve-function/11886 "2019-07-16T22:28:04Z")

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Hello, I want to solve a function using NLsolve, which has parameters. I do not want to pass them using global variables. Simplified example: using NLsolve function f!(F, x) global a, b F\[1\] = a \* sin(x\[1\]) + …

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## [DiffEqFlux with discrete time-dependent input](https://discourse.julialang.org/t/diffeqflux-with-discrete-time-dependent-input/26397)

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**Author:** [@mleprovost](https://discourse.julialang.org/u/mleprovost)\
**Replies:** 2\
**Last updated:** [July 16, 2019, 4:45pm UTC](https://discourse.julialang.org/t/diffeqflux-with-discrete-time-dependent-input/26397 "2019-07-16T16:45:45Z")

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Hello everyone, I would like to use DiffEqFlux to learn a discrete dynamic equation x(k+1) = A \* x(k) + B, where A(u(k)) and B(u(k)) are time-varying matrix and vector which depend on the input u(k) at the time step k.…

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## [Second order conic constraints with CPLEX](https://discourse.julialang.org/t/second-order-conic-constraints-with-cplex/26413)

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**Author:** [@giadasp](https://discourse.julialang.org/u/giadasp)\
**Replies:** 5\
**Last updated:** [July 16, 2019, 2:16pm UTC](https://discourse.julialang.org/t/second-order-conic-constraints-with-cplex/26413 "2019-07-16T14:16:52Z")

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I have to solve a MISOCP problem with JuMP and CPLEX but I really didn’t understand how to write the constraints with the new syntax in SecondOrderCone(). I need to minimize the squared norm of a vector in which I have …

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## [Following the object while Visualizing](https://discourse.julialang.org/t/following-the-object-while-visualizing/26421)

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**Author:** [@obi1kenobe](https://discourse.julialang.org/u/obi1kenobe)\
**Replies:** 0\
**Last updated:** [July 16, 2019, 1:27pm UTC](https://discourse.julialang.org/t/following-the-object-while-visualizing/26421 "2019-07-16T13:27:01Z")

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Hey, I am using the graphical interface GUI with MechanismVisualizer to visualize my objects. I have an object in floating but when it moves the camera stays fixed on the world object in the center. Is there a way for…

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## [Type error while using Scikit-learn and PyCall for logistic regression](https://discourse.julialang.org/t/type-error-while-using-scikit-learn-and-pycall-for-logistic-regression/26410)

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**Author:** [@richie96](https://discourse.julialang.org/u/richie96)\
**Replies:** 0\
**Last updated:** [July 16, 2019, 10:24am UTC](https://discourse.julialang.org/t/type-error-while-using-scikit-learn-and-pycall-for-logistic-regression/26410 "2019-07-16T10:24:31Z")

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Hi, I have been trying to change a python code into Julia and when trying to fit the Logisic regression model using: @sk\_import linear\_model: LogisticRegression model = fit!(LogisticRegression(multi\_class=“multinomial…

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## [OnlineStats and regularization hyperparameters](https://discourse.julialang.org/t/onlinestats-and-regularization-hyperparameters/26140)

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**Author:** [@GdMacmillan](https://discourse.julialang.org/u/GdMacmillan)\
**Replies:** 5\
**Last updated:** [July 16, 2019, 1:40am UTC](https://discourse.julialang.org/t/onlinestats-and-regularization-hyperparameters/26140 "2019-07-16T01:40:36Z")

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I’m working with online stats to learn a classification model. I have a sparse array of tfidf features and binary target variables and have figured out how to train my model. The API documentation is lacking and needs to…

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## [@everywhere using FFTW produces "Package FFTW not found in current path"](https://discourse.julialang.org/t/everywhere-using-fftw-produces-package-fftw-not-found-in-current-path/26342)

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**Author:** [@egcjm](https://discourse.julialang.org/u/egcjm)\
**Replies:** 3\
**Last updated:** [July 15, 2019, 1:35pm UTC](https://discourse.julialang.org/t/everywhere-using-fftw-produces-package-fftw-not-found-in-current-path/26342 "2019-07-15T13:35:20Z")

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\[This issue has been discussed in various places; unfortunately none of the proposed fixes seems to work for me\]. When executing @everywhere CertainPackages I get an error. As suggested by several I start with: using…

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## [CuArrays/CUDAnative/CUDAdrv equivalent to cudaMemcpy3DAsync?](https://discourse.julialang.org/t/cuarrays-cudanative-cudadrv-equivalent-to-cudamemcpy3dasync/26182)

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**Author:** [@samo](https://discourse.julialang.org/u/samo)\
**Replies:** 10\
**Last updated:** [July 15, 2019, 9:52am UTC](https://discourse.julialang.org/t/cuarrays-cudanative-cudadrv-equivalent-to-cudamemcpy3dasync/26182 "2019-07-15T09:52:59Z")

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What is the CuArrays/CUDAnative/CUDAdrv equivalent to cudaMemcpy3DAsync? More precisely, I am looking for how to do the equivalent of the following CUDA C code, which copies a XZ-plane of a 3-D device array to a contigu…

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## [How to create cuda streams with different priorities?](https://discourse.julialang.org/t/how-to-create-cuda-streams-with-different-priorities/25791)

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**Author:** [@samo](https://discourse.julialang.org/u/samo)\
**Replies:** 11\
**Last updated:** [July 15, 2019, 9:46am UTC](https://discourse.julialang.org/t/how-to-create-cuda-streams-with-different-priorities/25791 "2019-07-15T09:46:34Z")

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Question How can we create (nonblocking) cuda streams with different priorities? That is, how can we do with CuArrays/CUDAnative/CUDAdrv the equivivalent to the following lines of CUDA code? cudaStream\_t streams\[2\]; in…

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## [Parallel feedforward computation with RNN](https://discourse.julialang.org/t/parallel-feedforward-computation-with-rnn/26378)

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**Author:** [@HenriDeh](https://discourse.julialang.org/u/HenriDeh)\
**Replies:** 0\
**Last updated:** [July 15, 2019, 8:51am UTC](https://discourse.julialang.org/t/parallel-feedforward-computation-with-rnn/26378 "2019-07-15T08:51:05Z")

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Say you have a sample of 3 observations-label as a training set for a standard fully connected NN. To parallelize the computation of the loss (and the gradient) of each label, you can feed the three observations to the N…

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## [VariablePrimalStart() is not supported by the model and LazyBridgeOptimizer](https://discourse.julialang.org/t/variableprimalstart-is-not-supported-by-the-model-and-lazybridgeoptimizer/25447)

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**Author:** [@Alxg](https://discourse.julialang.org/u/Alxg)\
**Replies:** 3\
**Last updated:** [July 14, 2019, 11:14am UTC](https://discourse.julialang.org/t/variableprimalstart-is-not-supported-by-the-model-and-lazybridgeoptimizer/25447 "2019-07-14T11:14:31Z")

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I’m trying to do a MIP-start on a multicommodity capacitated fixed-charge network design problem using JuMP 0.19 and CPLEX 12.8 with the set\_start\_value function, but I keep getting the following error : MathOptInterfac…

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## [UserWarning: Legend does not support Line2D object](https://discourse.julialang.org/t/userwarning-legend-does-not-support-line2d-object/970)

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**Author:** [@chobbes](https://discourse.julialang.org/u/chobbes)\
**Replies:** 11\
**Last updated:** [July 13, 2019, 10:00pm UTC](https://discourse.julialang.org/t/userwarning-legend-does-not-support-line2d-object/970 "2019-07-13T22:00:52Z")

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When plotting with legends using PyPlot, I got the following error. What may this error be caused by? /usr/lib/pymodules/python2.7/matplotlib/legend.py:613: UserWarning: Legend does not support \[\<matplotlib.lines.Line2D…

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## [Changing the binding of a variable in a closure](https://discourse.julialang.org/t/changing-the-binding-of-a-variable-in-a-closure/26297)

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**Author:** [@dmbates](https://discourse.julialang.org/u/dmbates)\
**Replies:** 5\
**Last updated:** [July 13, 2019, 6:22pm UTC](https://discourse.julialang.org/t/changing-the-binding-of-a-variable-in-a-closure/26297 "2019-07-13T18:22:32Z")

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I am labeling this question as “statistics” because the motivation comes from a statistical application. The tl: dr version is that I want to change the binding of a variable in a closure within a loop. The function it…

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## [CPU utilization in parallel computing](https://discourse.julialang.org/t/cpu-utilization-in-parallel-computing/26320)

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**Author:** [@FujiwaraTakumiEH](https://discourse.julialang.org/u/FujiwaraTakumiEH)\
**Replies:** 1\
**Last updated:** [July 13, 2019, 2:32pm UTC](https://discourse.julialang.org/t/cpu-utilization-in-parallel-computing/26320 "2019-07-13T14:32:07Z")

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When using @distributed parallel code, if the amount of data needed to be manipulated is large, will CPU utilization reach 100%, which can be used as a basis for successful parallel？ (of course, direct test runtime is mo…

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## [Automatic conversion of ^ to repeated \* without applying promotion rule](https://discourse.julialang.org/t/automatic-conversion-of-to-repeated-without-applying-promotion-rule/26261)

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**Author:** [@brianguenter](https://discourse.julialang.org/u/brianguenter)\
**Replies:** 7\
**Last updated:** [July 13, 2019, 12:41pm UTC](https://discourse.julialang.org/t/automatic-conversion-of-to-repeated-without-applying-promotion-rule/26261 "2019-07-13T12:41:36Z")

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I’m writing a symbolic differentiation library for Julia (see https://www.microsoft.com/en-us/research/wp-content/uploads/2016/02/main-65.pdf if you are interested) and ran into a problem with promote rules and ^. In an …

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## [Issues install Coluna.jl oj Julia 1.1](https://discourse.julialang.org/t/issues-install-coluna-jl-oj-julia-1-1/26298)

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**Author:** [@rakesh\_gupta](https://discourse.julialang.org/u/rakesh_gupta)\
**Replies:** 1\
**Last updated:** [July 12, 2019, 10:59pm UTC](https://discourse.julialang.org/t/issues-install-coluna-jl-oj-julia-1-1/26298 "2019-07-12T22:59:59Z")

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Hi - I am having a lot of trouble installing Coluna.jl on the 1.04 version of Julia. The command I am using is: add GitHub - atoptima/Coluna.jl: Branch-and-Price-and-Cut in Julia Which should ostensibly work out of the…

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## [Use Cbc with Parametron? (ERROR: MathOptInterface.SetAttributeNotAllowed)](https://discourse.julialang.org/t/use-cbc-with-parametron-error-mathoptinterface-setattributenotallowed/26263)

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**Author:** [@ianfiske](https://discourse.julialang.org/u/ianfiske)\
**Replies:** 6\
**Last updated:** [July 12, 2019, 10:31pm UTC](https://discourse.julialang.org/t/use-cbc-with-parametron-error-mathoptinterface-setattributenotallowed/26263 "2019-07-12T22:31:21Z")

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I am trying to adapt the first Parametron README.md example to use Cbc because I’ll need binary variables. However, the example does not work out of the box with Cbc.Optimizer(). I’ve worked through some of the errors …

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## [Indexing a const array with a JuMP variable](https://discourse.julialang.org/t/indexing-a-const-array-with-a-jump-variable/26283)

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**Author:** [@bocc](https://discourse.julialang.org/u/bocc)\
**Replies:** 2\
**Last updated:** [July 12, 2019, 2:41pm UTC](https://discourse.julialang.org/t/indexing-a-const-array-with-a-jump-variable/26283 "2019-07-12T14:41:16Z")

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Hello, let’s assume I have multiple 2D arrays (maps, tables…), each row of those belongs to a single design in a Pareto set (objective & parameter values). I want to optimize on the combinations of those, therefore (I …

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## [How to programmatically check optimisation status in JuMP \>= 0.19](https://discourse.julialang.org/t/how-to-programmatically-check-optimisation-status-in-jump-0-19/26289)

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**Author:** [@sylvaticus](https://discourse.julialang.org/u/sylvaticus)\
**Replies:** 2\
**Last updated:** [July 12, 2019, 2:04pm UTC](https://discourse.julialang.org/t/how-to-programmatically-check-optimisation-status-in-jump-0-19/26289 "2019-07-12T14:04:41Z")

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Which is the equivalent of status=solve(model); if status == :Optimal in JuMP \>= 0.19 ? optimize!(model); if termination\_status(model) == ????

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## [CUDAnative: simple and nice way to define type for all integer/float literals?; size() returning UInt32?](https://discourse.julialang.org/t/cudanative-simple-and-nice-way-to-define-type-for-all-integer-float-literals-size-returning-uint32/26227)

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**Author:** [@samo](https://discourse.julialang.org/u/samo)\
**Replies:** 5\
**Last updated:** [July 12, 2019, 10:37am UTC](https://discourse.julialang.org/t/cudanative-simple-and-nice-way-to-define-type-for-all-integer-float-literals-size-returning-uint32/26227 "2019-07-12T10:37:15Z")

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The following code is the computation kernel of a small heat diffusion application in 3-D: function diffusion3D\_kernel!(Te2, Te, Ci, lam, dt, dx, dy, dz) \_dx = 1.0/dx; # \_dx could obviously be passed as argument ins…

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## [How can I add to ML model together in Flux](https://discourse.julialang.org/t/how-can-i-add-to-ml-model-together-in-flux/26271)

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**Author:** [@Lyupinpin](https://discourse.julialang.org/u/Lyupinpin)\
**Replies:** 2\
**Last updated:** [July 12, 2019, 5:43am UTC](https://discourse.julialang.org/t/how-can-i-add-to-ml-model-together-in-flux/26271 "2019-07-12T05:43:21Z")

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Like I have two model now M1=Chain( Dense(2,10), Dense(10,10,relu), Dense(10,10,relu), Dense(10,10,relu), Dense(10,1) ) M2=Chain( Dense(2,10), Dense(10,10,relu), Dense(10,10,relu), Dense(10,10,relu), Dense(1…

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## [Optim; Hessian or Hessian free?](https://discourse.julialang.org/t/optim-hessian-or-hessian-free/26209)

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**Author:** [@krenova](https://discourse.julialang.org/u/krenova)\
**Replies:** 15\
**Last updated:** [July 11, 2019, 9:51pm UTC](https://discourse.julialang.org/t/optim-hessian-or-hessian-free/26209 "2019-07-11T21:51:28Z")

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Hi, In the documentation for the Optim package I note the following statement with regards to the choice of algorithm: When you do not have an explicit Hessian or when the dimension becomes large enough that the linea…

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## [Thousands of matrix multiplications using CuArray](https://discourse.julialang.org/t/thousands-of-matrix-multiplications-using-cuarray/26222)

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**Author:** [@joseph\_bouvard](https://discourse.julialang.org/u/joseph_bouvard)\
**Replies:** 5\
**Last updated:** [July 11, 2019, 2:49pm UTC](https://discourse.julialang.org/t/thousands-of-matrix-multiplications-using-cuarray/26222 "2019-07-11T14:49:02Z")

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Using CuArray.jl it was possible to improve the following code at about 7x when compare to the analogue computation executed on host. However, it is still disappointing for my purposes (53.122 s running on a Tesla K40c w…

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## [Flux unable to differentiate an embedding layer](https://discourse.julialang.org/t/flux-unable-to-differentiate-an-embedding-layer/26067)

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**Author:** [@merckxiaan](https://discourse.julialang.org/u/merckxiaan)\
**Replies:** 3\
**Last updated:** [July 11, 2019, 10:11am UTC](https://discourse.julialang.org/t/flux-unable-to-differentiate-an-embedding-layer/26067 "2019-07-11T10:11:01Z")

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I’ve made an embedding layer that should be able to embed a batched input. The forward pass seems to work great, I get back an array with the dimensions I expect. The backward pass however, doesn’t work. I get an error …

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## [DistributedArray operation fails](https://discourse.julialang.org/t/distributedarray-operation-fails/26177)

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**Author:** [@monty](https://discourse.julialang.org/u/monty)\
**Replies:** 3\
**Last updated:** [July 11, 2019, 8:24am UTC](https://discourse.julialang.org/t/distributedarray-operation-fails/26177 "2019-07-11T08:24:27Z")

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da = DistributedArrays.distribute(rand(10,10)) da' \* da works. However, da \* da' fails. Any suggestions why and how it can be fixed? Thank you very much!

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