# Specific Domains

**URL:** https://discourse.julialang.org/c/domain/10.md?no_subcategories=false&page=401

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**Page:** 402

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## [Easiest way to do "replace col1 = col2 if col3" in a dataframe](https://discourse.julialang.org/t/easiest-way-to-do-replace-col1-col2-if-col3-in-a-dataframe/51891)

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**Author:** [@RangeFu](https://discourse.julialang.org/u/RangeFu)\
**Replies:** 3\
**Last updated:** [December 16, 2020, 10:23am UTC](https://discourse.julialang.org/t/easiest-way-to-do-replace-col1-col2-if-col3-in-a-dataframe/51891 "2020-12-16T10:23:54Z")

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A very common operation in data manipulation: Update in-place col1 from col2 but only for rows where conditions hold for col3. If we stick to DataFrames, it has to be: dt\[dt.c, a\] = dt\[dt.c, b\] so we have to carry dt. …

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## [Weights from neural network as interaction score between pairs](https://discourse.julialang.org/t/weights-from-neural-network-as-interaction-score-between-pairs/51921)

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**Author:** [@alperyilmaz](https://discourse.julialang.org/u/alperyilmaz)\
**Replies:** 0\
**Last updated:** [December 16, 2020, 9:05am UTC](https://discourse.julialang.org/t/weights-from-neural-network-as-interaction-score-between-pairs/51921 "2020-12-16T09:05:52Z")

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The question is using genes as example but I thought “Machine Learning” section is more suitable for this question. Because the concept is independent from genes, might be applicable to other domains. Suppose we have ma…

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## [Help to plot in Julia](https://discourse.julialang.org/t/help-to-plot-in-julia/51910)

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**Author:** [@Enrique](https://discourse.julialang.org/u/Enrique)\
**Replies:** 6\
**Last updated:** [December 16, 2020, 8:47am UTC](https://discourse.julialang.org/t/help-to-plot-in-julia/51910 "2020-12-16T08:47:58Z")

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I love Julia, but I still do not figure out how to make pretty plots. The figure size is in pixels rather than inches, which complicates things when you want to set font sizes (in points). LaTeXStrings does not work in W…

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## [3d plot plotly vs plotlyjs](https://discourse.julialang.org/t/3d-plot-plotly-vs-plotlyjs/51907)

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**Author:** [@espin](https://discourse.julialang.org/u/espin)\
**Replies:** 1\
**Last updated:** [December 16, 2020, 6:17am UTC](https://discourse.julialang.org/t/3d-plot-plotly-vs-plotlyjs/51907 "2020-12-16T06:17:08Z")

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So I have a 2 dimensional array I want to plot as a 3d surface in plotlyjs, the problem is that is not working on plotlyjs even though it works ok on plotly. Here is an example: using Plots plotly() A=reshape(repeat(si…

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## [Find Taylor Series of a Function](https://discourse.julialang.org/t/find-taylor-series-of-a-function/51847)

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**Author:** [@brett\_knoss](https://discourse.julialang.org/u/brett_knoss)\
**Replies:** 11\
**Last updated:** [December 16, 2020, 3:52am UTC](https://discourse.julialang.org/t/find-taylor-series-of-a-function/51847 "2020-12-16T03:52:52Z")

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I’m completely at a loss for finding the Taylor Series of a function using TaylorSeries.jl using TaylorSeries using QuadGK f(x)=cos(x) t=Taylor1(f(pi/2),2) quadgk(x-\>cos(t), 22pi/45,pi/2;order=2)

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## [Dimension mismatch. "Cannot sum matrices" when doing a product](https://discourse.julialang.org/t/dimension-mismatch-cannot-sum-matrices-when-doing-a-product/51869)

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**Author:** [@prit](https://discourse.julialang.org/u/prit)\
**Replies:** 1\
**Last updated:** [December 15, 2020, 9:17pm UTC](https://discourse.julialang.org/t/dimension-mismatch-cannot-sum-matrices-when-doing-a-product/51869 "2020-12-15T21:17:36Z")

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I have the following code: using JuMP using MosekTools K = 3 N = 2 penalties = \[1.0, 3.9, 8.7\] function fac1(r::Number, i::Number, l::Number) fac1 = 1.0 for m in 0:r-1 fac1 \*= (i-m)\*(l-m) end ret…

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## [Expand row to multiple rows](https://discourse.julialang.org/t/expand-row-to-multiple-rows/51872)

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**Author:** [@rocco\_sprmnt21](https://discourse.julialang.org/u/rocco_sprmnt21)\
**Replies:** 11\
**Last updated:** [December 15, 2020, 5:50pm UTC](https://discourse.julialang.org/t/expand-row-to-multiple-rows/51872 "2020-12-15T17:50:44Z")

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I have this data: df=DataFrame(name=\["aaa","bbbb","ccc"\], frqty=\["apple\\\\4\\\\melon\\\\5","plume\\\\12","graphes\\\\7\\\\mango\\\\9\\\\persic\\\\11"\]) the goal is to get a group of rows for each name and two …

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## [Promote operation; report this](https://discourse.julialang.org/t/promote-operation-report-this/51871)

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**Author:** [@prit](https://discourse.julialang.org/u/prit)\
**Replies:** 1\
**Last updated:** [December 15, 2020, 3:35pm UTC](https://discourse.julialang.org/t/promote-operation-report-this/51871 "2020-12-15T15:35:29Z")

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I have the following code in which a constraint is giving a “promote operation error”: using JuMP using MosekTools K = 3 N = 2 penalties = \[1.0, 3.9, 8.7\] function fac1(r::Number, i::Number, l::Number) fac1 = 1.0 …

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## [ReverseDiff: differentiating a function with an indexing argument](https://discourse.julialang.org/t/reversediff-differentiating-a-function-with-an-indexing-argument/51530)

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**Author:** [@jacobusmmsmit](https://discourse.julialang.org/u/jacobusmmsmit)\
**Replies:** 5\
**Last updated:** [December 15, 2020, 12:09pm UTC](https://discourse.julialang.org/t/reversediff-differentiating-a-function-with-an-indexing-argument/51530 "2020-12-15T12:09:52Z")

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I am looking to move from using ForwardDiff to ReverseDiff due to the speedup provided by compiled tapes. I would like to differentiate a function where one of the arguments is an index of the output, and then compile th…

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## [How to add, subtract, and take linear combinations of ODE solutions](https://discourse.julialang.org/t/how-to-add-subtract-and-take-linear-combinations-of-ode-solutions/51791)

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**Author:** [@CosmoProf](https://discourse.julialang.org/u/CosmoProf)\
**Replies:** 2\
**Last updated:** [December 15, 2020, 10:24am UTC](https://discourse.julialang.org/t/how-to-add-subtract-and-take-linear-combinations-of-ode-solutions/51791 "2020-12-15T10:24:55Z")

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Hi, I’m solving differential equations with different sets of initial conditions, and I’m trying to figure out how to take different linear combinations of the ODE solutions (added, subtracted, multiplied by different sc…

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## [Image rotation](https://discourse.julialang.org/t/image-rotation/2637)

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**Author:** [@yalexand](https://discourse.julialang.org/u/yalexand)\
**Replies:** 10\
**Last updated:** [December 15, 2020, 10:17am UTC](https://discourse.julialang.org/t/image-rotation/2637 "2020-12-15T10:17:14Z")

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Hi All, I can’t find an analog for Matlab “imrotate” function. Maybe I overlooked it, or really there isn’t such thing? Here it is in Matlab, to save you clicking: imrotate Rotate image. B = imrotate(A,ANGLE) rot…

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## [Retrieving the Hessian, and eventually calculating the standard errors using JuMP](https://discourse.julialang.org/t/retrieving-the-hessian-and-eventually-calculating-the-standard-errors-using-jump/51823)

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**Author:** [@jovansam](https://discourse.julialang.org/u/jovansam)\
**Replies:** 3\
**Last updated:** [December 15, 2020, 9:47am UTC](https://discourse.julialang.org/t/retrieving-the-hessian-and-eventually-calculating-the-standard-errors-using-jump/51823 "2020-12-15T09:47:47Z")

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After obtaining the optimum, I am interested in finding the Hessian. I then intend to use this to find standard errors. More like what is done here, but that code refers to old JuMP and I am having trouble translating it…

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## [Julia not accepting this constraint. No method matching cartesian index](https://discourse.julialang.org/t/julia-not-accepting-this-constraint-no-method-matching-cartesian-index/51850)

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**Author:** [@prit](https://discourse.julialang.org/u/prit)\
**Replies:** 1\
**Last updated:** [December 15, 2020, 9:13am UTC](https://discourse.julialang.org/t/julia-not-accepting-this-constraint-no-method-matching-cartesian-index/51850 "2020-12-15T09:13:33Z")

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I have the following code in which the JuMP constraint is throwing an error. using JuMP using MosekTools K = 3 N = 2 penalties = \[1.0, 3.9, 8.7\] function A\_tau(r::Number, n::Number, tau::Float64) fac = 1 for m …

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## [Again, another simple 2D plotting tool](https://discourse.julialang.org/t/again-another-simple-2d-plotting-tool/51837)

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**Author:** [@ig-or](https://discourse.julialang.org/u/ig-or)\
**Replies:** 0\
**Last updated:** [December 15, 2020, 12:09am UTC](https://discourse.julialang.org/t/again-another-simple-2d-plotting-tool/51837 "2020-12-15T00:09:49Z")

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Hello, made another 2D plotting tool for Julia… QWTWPlot.jl maybe it could be useful for quick data analysis. It does not have many features but allows to quickly create a number of “connected” plots, like when you mov…

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## [DoubleFloats.jl -\> Double128 | Quad64?](https://discourse.julialang.org/t/doublefloats-jl-double128-quad64/51049)

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**Author:** [@lrnv](https://discourse.julialang.org/u/lrnv)\
**Replies:** 54\
**Last updated:** [December 14, 2020, 11:10pm UTC](https://discourse.julialang.org/t/doublefloats-jl-double128-quad64/51049 "2020-12-14T23:10:39Z")

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Hey, I need some kind of high precision arithmetics to do computations, and I’m trying to find the best balance between runtime and precision. Using BigFloat, i found out that 256bits BigFloats give me good enough resul…

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## [Unknown error when using ccall to work with Apache Arrow's GLib interface](https://discourse.julialang.org/t/unknown-error-when-using-ccall-to-work-with-apache-arrows-glib-interface/51794)

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**Author:** [@s-kap](https://discourse.julialang.org/u/s-kap)\
**Replies:** 3\
**Last updated:** [December 14, 2020, 10:21pm UTC](https://discourse.julialang.org/t/unknown-error-when-using-ccall-to-work-with-apache-arrows-glib-interface/51794 "2020-12-14T22:21:39Z")

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Hey all, Context: Apache Arrow is an in memory columnar format has some very speedy IO implementations in c++ has a C interface using GLib Since it’s an in-memory format, I’d like to perform IO in cpp, and then conv…

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## [List of JuMP solvers that have a compute\_conflict! function implemented](https://discourse.julialang.org/t/list-of-jump-solvers-that-have-a-compute-conflict-function-implemented/51825)

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**Author:** [@bhalonen](https://discourse.julialang.org/u/bhalonen)\
**Replies:** 2\
**Last updated:** [December 14, 2020, 9:05pm UTC](https://discourse.julialang.org/t/list-of-jump-solvers-that-have-a-compute-conflict-function-implemented/51825 "2020-12-14T21:05:19Z")

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I am interested in using the compute\_conflict! function in JuMP, I noticed that Gurobi.jl and CPLEX.jl are cited in the documentation in a comment as available solvers. I also found that Xpress.jl has the same functional…

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## [Gurobi constraint](https://discourse.julialang.org/t/gurobi-constraint/51798)

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**Author:** [@jay-dave](https://discourse.julialang.org/u/jay-dave)\
**Replies:** 2\
**Last updated:** [December 14, 2020, 8:59pm UTC](https://discourse.julialang.org/t/gurobi-constraint/51798 "2020-12-14T20:59:55Z")

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Below is the minimum example of the model I am able to solve. Why is the constraint @constraint(model, Cost == (x-y)\*z) allowed in Gurobi? Isn’t it nonlinear? using JuMP using Gurobi model = Model(with\_optimizer(Gurobi.…

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## [In-place allocations in DifferentialEquations](https://discourse.julialang.org/t/in-place-allocations-in-differentialequations/51813)

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**Author:** [@oeyd](https://discourse.julialang.org/u/oeyd)\
**Replies:** 9\
**Last updated:** [December 14, 2020, 7:59pm UTC](https://discourse.julialang.org/t/in-place-allocations-in-differentialequations/51813 "2020-12-14T19:59:15Z")

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I am wondering why the code below allocates as much memory as it does despite using an in-place function definition. Is this normal or is there a way to avoid these allocations? using DifferentialEquations function ode…

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## [Difference result between insertcols! and transform! in spreading one column to many columns](https://discourse.julialang.org/t/difference-result-between-insertcols-and-transform-in-spreading-one-column-to-many-columns/51777)

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**Author:** [@rocco\_sprmnt21](https://discourse.julialang.org/u/rocco_sprmnt21)\
**Replies:** 4\
**Last updated:** [December 14, 2020, 7:48pm UTC](https://discourse.julialang.org/t/difference-result-between-insertcols-and-transform-in-spreading-one-column-to-many-columns/51777 "2020-12-14T19:48:05Z")

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I tried to understand how this script here works and I tried to reproduce it in other ways: this with insertcols! it seems to work df=DataFrame(name=\["James Smith 39","Michel Smith 41","Maria Garcia 19"\], …

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## [Incompatibility Queryverse / DataFrames?](https://discourse.julialang.org/t/incompatibility-queryverse-dataframes/51822)

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**Author:** [@tlorans](https://discourse.julialang.org/u/tlorans)\
**Replies:** 2\
**Last updated:** [December 14, 2020, 7:28pm UTC](https://discourse.julialang.org/t/incompatibility-queryverse-dataframes/51822 "2020-12-14T19:28:58Z")

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Hello, I try to use simultaneously Queryverse and DataFrames packages, but it seems there is some incompatibility: julia\> Pkg.add("Queryverse") Updating registry at \`~/.julia/registries/General\` ####################…

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## [Package for time series?](https://discourse.julialang.org/t/package-for-time-series/29555)

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**Author:** [@Donkeyfish87](https://discourse.julialang.org/u/Donkeyfish87)\
**Replies:** 10\
**Last updated:** [December 14, 2020, 5:59pm UTC](https://discourse.julialang.org/t/package-for-time-series/29555 "2020-12-14T17:59:42Z")

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Are there any Julia packages for time series analysis? Like arma, arima, vector autoregressions etc. I’ve tried looking around a bit, but didn’t find anything. Thanks.

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## [Multiple Constraints using JuMP for unbounded knapsack](https://discourse.julialang.org/t/multiple-constraints-using-jump-for-unbounded-knapsack/51015)

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**Author:** [@TheMEGuy](https://discourse.julialang.org/u/TheMEGuy)\
**Replies:** 6\
**Last updated:** [December 14, 2020, 2:58pm UTC](https://discourse.julialang.org/t/multiple-constraints-using-jump-for-unbounded-knapsack/51015 "2020-12-14T14:58:17Z")

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I am new to programming, so I hope that the description of my probleme is accurate: Based on knapsack, I used JuMP and GLPK to come up with a solution for the unbounded knapsack problem.: function unbounded\_knapsack(va…

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## [Julia wrapper for libssh?](https://discourse.julialang.org/t/julia-wrapper-for-libssh/46041)

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**Author:** [@grero](https://discourse.julialang.org/u/grero)\
**Replies:** 4\
**Last updated:** [December 14, 2020, 9:03am UTC](https://discourse.julialang.org/t/julia-wrapper-for-libssh/46041 "2020-12-14T09:03:03Z")

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Is there a julia wrapper for libssh somewhere? I would like to be able to transfer a part of a large file located on a remote server using sftp (the file itself could be 100G, but I might be interested in a small subset …

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## [Fast CNN inference](https://discourse.julialang.org/t/fast-cnn-inference/51761)

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**Author:** [@Fabrice\_Rosay](https://discourse.julialang.org/u/Fabrice_Rosay)\
**Replies:** 3\
**Last updated:** [December 14, 2020, 8:01am UTC](https://discourse.julialang.org/t/fast-cnn-inference/51761 "2020-12-14T08:01:22Z")

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Hi, I’m currently using Knet and Flux for doing alphazero like calculations. As the botlleneck is the many inferences needed i was wondering if it would be possible to wrap TensorRT like https://github.com/zerollzeng/ti…

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## [Changing many rows to single row julia1.5.3](https://discourse.julialang.org/t/changing-many-rows-to-single-row-julia1-5-3/51615)

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**Author:** [@orthoeng](https://discourse.julialang.org/u/orthoeng)\
**Replies:** 8\
**Last updated:** [December 13, 2020, 11:51pm UTC](https://discourse.julialang.org/t/changing-many-rows-to-single-row-julia1-5-3/51615 "2020-12-13T23:51:12Z")

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I have a dataset that is 1miil x 70 but with in the rows many columns have duplicate entries. Likewise there are many rows that are unique columns also. Example | ID | age | location | street …

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## [Warning: macos 10.12.\* bug with SharedArray: shm\_open() failed](https://discourse.julialang.org/t/warning-macos-10-12-bug-with-sharedarray-shm-open-failed/10471)

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**Author:** [@iwelch](https://discourse.julialang.org/u/iwelch)\
**Replies:** 3\
**Last updated:** [December 13, 2020, 10:23pm UTC](https://discourse.julialang.org/t/warning-macos-10-12-bug-with-sharedarray-shm-open-failed/10471 "2020-12-13T22:23:38Z")

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The following program triggers a bug in macos 10.12.\*, but not in 10.13.\* : (nprocs()\>1) || addprocs(1) function sharedarray\_parallel\_sum() sa = SharedArray{Float64}(5) @sync @parallel for i=1:5; sa\[i\] = timing…

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## [Just curious: why most of packages in github.com/JuliaQuant organization not updated for a quite long time](https://discourse.julialang.org/t/just-curious-why-most-of-packages-in-github-com-juliaquant-organization-not-updated-for-a-quite-long-time/51707)

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**Author:** [@liuyxpp](https://discourse.julialang.org/u/liuyxpp)\
**Replies:** 1\
**Last updated:** [December 13, 2020, 4:41pm UTC](https://discourse.julialang.org/t/just-curious-why-most-of-packages-in-github-com-juliaquant-organization-not-updated-for-a-quite-long-time/51707 "2020-12-13T16:41:53Z")

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I am searching for an alternative to Backtrader in Python, or any backtesting framework in Julia, without any luck. How do people here in Julia do trade backtesting?

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## [Error when using 'All' in 'DataFrames.combine'](https://discourse.julialang.org/t/error-when-using-all-in-dataframes-combine/49045)

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**Author:** [@metab0t](https://discourse.julialang.org/u/metab0t)\
**Replies:** 2\
**Last updated:** [December 13, 2020, 3:47pm UTC](https://discourse.julialang.org/t/error-when-using-all-in-dataframes-combine/49045 "2020-12-13T15:47:53Z")

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I try the following code: using DataFrames df = DataFrame(a=1:3, b=4:6) combine(df, All(:) .=\> sum) and get error: ERROR: MethodError: no method matching length(::All{Tuple{Colon}}) Closest candidates are: length(::…

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## [AMDGPU install errors](https://discourse.julialang.org/t/amdgpu-install-errors/51492)

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**Author:** [@saltchunkmary](https://discourse.julialang.org/u/saltchunkmary)\
**Replies:** 12\
**Last updated:** [December 13, 2020, 1:25pm UTC](https://discourse.julialang.org/t/amdgpu-install-errors/51492 "2020-12-13T13:25:59Z")

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Hi, first time poster here… not that that means anything… in need of a little help. Whilst building AMDGPU I am getting errors as below: ┌ Error: Error building AMDGPU: │ WARNING: redefinition of constant config\_path.…

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