# Specific Domains

**URL:** https://discourse.julialang.org/c/domain/10.md?page=538

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**Page:** 539

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## [Apply weights in JuliaDB groupby](https://discourse.julialang.org/t/apply-weights-in-juliadb-groupby/10817)

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**Author:** [@pmarg](https://discourse.julialang.org/u/pmarg)\
**Replies:** 3\
**Last updated:** [May 10, 2018, 5:33pm UTC](https://discourse.julialang.org/t/apply-weights-in-juliadb-groupby/10817 "2018-05-10T17:33:12Z")

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Hi, I’ve been struggling to find a way to calculate the weighted descriptive statistics in JuliaDB using the groupby function. Assuming that “w” is a column of the table DB with sampling weights, I would like to find so…

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## [Times of events with DifferentialEquations.jl](https://discourse.julialang.org/t/times-of-events-with-differentialequations-jl/10811)

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**Author:** [@dawbarton](https://discourse.julialang.org/u/dawbarton)\
**Replies:** 5\
**Last updated:** [May 10, 2018, 3:46pm UTC](https://discourse.julialang.org/t/times-of-events-with-differentialequations-jl/10811 "2018-05-10T15:46:46Z")

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I’m using DifferentialEquations.jl for the first time in a while (it’s changed a bit :slight\_smile:) and I’m trying to work out how to get the times at which events happen with a ContinuousCallback function when integrat…

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## [Mxnet strange BoundsError](https://discourse.julialang.org/t/mxnet-strange-boundserror/10807)

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**Author:** [@han-so1omon](https://discourse.julialang.org/u/han-so1omon)\
**Replies:** 0\
**Last updated:** [May 9, 2018, 11:31pm UTC](https://discourse.julialang.org/t/mxnet-strange-boundserror/10807 "2018-05-09T23:31:06Z")

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Training a network that outputs mxnet.NDArrays shape (27,1). I created a 3d array of labels of shape (27,1,210). Creation of data provider and subsequent training looks like the following: navDataIter = mx.ArrayDataPro…

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## [Passing a function as an objective function in JuMP](https://discourse.julialang.org/t/passing-a-function-as-an-objective-function-in-jump/10745)

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**Author:** [@jayce\_ram](https://discourse.julialang.org/u/jayce_ram)\
**Replies:** 2\
**Last updated:** [May 9, 2018, 9:08am UTC](https://discourse.julialang.org/t/passing-a-function-as-an-objective-function-in-jump/10745 "2018-05-09T09:08:48Z")

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Anyone knows if it is possible and how to pass a function as an objective function in JuMP? I have read the documentation but i haven’t find anything about it. I have many sum as objective and I would like to write it i…

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## [Stack overflow on cuda](https://discourse.julialang.org/t/stack-overflow-on-cuda/10735)

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**Author:** [@swethmandava](https://discourse.julialang.org/u/swethmandava)\
**Replies:** 9\
**Last updated:** [May 9, 2018, 8:02am UTC](https://discourse.julialang.org/t/stack-overflow-on-cuda/10735 "2018-05-09T08:02:41Z")

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I’m trying to write a radix sort in julia using cuda but I get a stack overflow error. I’ve got it down to a bare minimum kernel and am not sure what’s wrong with it. function increment\_with\_block\_sums(d\_predicateScan::…

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## [Store arrays in juliadb table?](https://discourse.julialang.org/t/store-arrays-in-juliadb-table/10788)

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**Author:** [@LaurentPlagne](https://discourse.julialang.org/u/LaurentPlagne)\
**Replies:** 0\
**Last updated:** [May 8, 2018, 10:24pm UTC](https://discourse.julialang.org/t/store-arrays-in-juliadb-table/10788 "2018-05-08T22:24:57Z")

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Hi, I would like store a collection of performance measurements consisting in arrays of floats. Each measurement is characterized by several attributes . I would like to be able to filter the measurements relatively to …

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## [Efficient linear algebra for large-scale problems in JuMP](https://discourse.julialang.org/t/efficient-linear-algebra-for-large-scale-problems-in-jump/10715)

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**Author:** [@ExpandingMan](https://discourse.julialang.org/u/ExpandingMan)\
**Replies:** 6\
**Last updated:** [May 8, 2018, 2:38pm UTC](https://discourse.julialang.org/t/efficient-linear-algebra-for-large-scale-problems-in-jump/10715 "2018-05-08T14:38:55Z")

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Hello all. I’ve finally had a chance to sit down and look carefully at some of the code in JuMP 0.19. In my work I very frequently have to do problems with \\sim 10^6 variables. Obviously implementing these involves a…

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## [Bug with \`linecolor = cgrad()\`?](https://discourse.julialang.org/t/bug-with-linecolor-cgrad/10775)

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**Author:** [@BLI](https://discourse.julialang.org/u/BLI)\
**Replies:** 2\
**Last updated:** [May 8, 2018, 11:27am UTC](https://discourse.julialang.org/t/bug-with-linecolor-cgrad/10775 "2018-05-08T11:27:16Z")

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I’m doing some parametric 3D plots, and want the line color to change with a parameter (e.g., time). So… suppose we have 3 states in an ODE, with solution vectors u1, u2, u3 that depend on a parameter (time) vector t. Su…

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## [GLM.jl, error on Binomial distribution, fixed number of trials](https://discourse.julialang.org/t/glm-jl-error-on-binomial-distribution-fixed-number-of-trials/10767)

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**Author:** [@hung-q-ngo](https://discourse.julialang.org/u/hung-q-ngo)\
**Replies:** 4\
**Last updated:** [May 8, 2018, 12:03am UTC](https://discourse.julialang.org/t/glm-jl-error-on-binomial-distribution-fixed-number-of-trials/10767 "2018-05-08T00:03:12Z")

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Hello: the following gives an error data = DataFrame(Y = \[0,3,1,7,1,0,7,5,1\], X1 = \[1,2,3,1,2,3,1,2,3\], X2 = \[1,1,1,2,2,2,3,3,3\]) model = glm(@formula(Y ~ X1 + X2), data, Binomial(10)) Error msg: ERROR: LoadError: Dom…

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## [I'm building a database using 'csv', I need to have the program read the tables and calculate the constraint and goal indices, to get the optimal solution, which commands should I use?](https://discourse.julialang.org/t/im-building-a-database-using-csv-i-need-to-have-the-program-read-the-tables-and-calculate-the-constraint-and-goal-indices-to-get-the-optimal-solution-which-commands-should-i-use/10759)

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**Author:** [@RaquelSantos](https://discourse.julialang.org/u/RaquelSantos)\
**Replies:** 2\
**Last updated:** [May 7, 2018, 2:04pm UTC](https://discourse.julialang.org/t/im-building-a-database-using-csv-i-need-to-have-the-program-read-the-tables-and-calculate-the-constraint-and-goal-indices-to-get-the-optimal-solution-which-commands-should-i-use/10759 "2018-05-07T14:04:39Z")

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I’m building a database using ‘csv’, I need to have the program read the tables and calculate the constraint and goal indices, to get the optimal solution, which commands should I use?

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## [Parallel mc recommendation](https://discourse.julialang.org/t/parallel-mc-recommendation/10711)

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**Author:** [@gideonsimpson](https://discourse.julialang.org/u/gideonsimpson)\
**Replies:** 8\
**Last updated:** [May 7, 2018, 12:07pm UTC](https://discourse.julialang.org/t/parallel-mc-recommendation/10711 "2018-05-07T12:07:26Z")

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For the following code, which runs independent chains of Random Walk Metropolis, there is the obvious potential for parallelization. I am wondering what strategies people would recommend. This is related to a prior que…

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## [TensorFlow.jl - Export/Import Meta Graph?](https://discourse.julialang.org/t/tensorflow-jl-export-import-meta-graph/9108)

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**Author:** [@einem83](https://discourse.julialang.org/u/einem83)\
**Replies:** 2\
**Last updated:** [May 7, 2018, 9:14am UTC](https://discourse.julialang.org/t/tensorflow-jl-export-import-meta-graph/9108 "2018-05-07T09:14:47Z")

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Hi experts i am struggling with exporting and importing a meta\_graph in TensorFlow.jl: tensorflow 1.4.0 TensorFlow.jl 0.8.0 julia 0.6.2 Here an example,. where i am struggling: using TensorFlow session = Session(Gr…

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## [Breaking ExcelReaders.jl update](https://discourse.julialang.org/t/breaking-excelreaders-jl-update/10624)

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**Author:** [@davidanthoff](https://discourse.julialang.org/u/davidanthoff)\
**Replies:** 2\
**Last updated:** [May 7, 2018, 4:43am UTC](https://discourse.julialang.org/t/breaking-excelreaders-jl-update/10624 "2018-05-07T04:43:28Z")

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Hi everyone, just a heads up that I’ve just released a new version of ExcelReaders.jl that is breaking. The new version removes all support for DataFrames.jl and no longer uses DataArrays.jl. But, fear not, you can sti…

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## [\[JuMP\] Get variable name from a model to use on another](https://discourse.julialang.org/t/jump-get-variable-name-from-a-model-to-use-on-another/10692)

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**Author:** [@abelsiqueira](https://discourse.julialang.org/u/abelsiqueira)\
**Replies:** 3\
**Last updated:** [May 5, 2018, 7:51pm UTC](https://discourse.julialang.org/t/jump-get-variable-name-from-a-model-to-use-on-another/10692 "2018-05-05T19:51:04Z")

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On JuMP, I have a model m = Model() @variable(m, x\[1:2\]) By passing m to a function, can I obtain the variable x to define a new model with x?

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## [\[JuMP\] Creating a Nonlinear Least Squares model](https://discourse.julialang.org/t/jump-creating-a-nonlinear-least-squares-model/10706)

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**Author:** [@abelsiqueira](https://discourse.julialang.org/u/abelsiqueira)\
**Replies:** 2\
**Last updated:** [May 5, 2018, 7:50pm UTC](https://discourse.julialang.org/t/jump-creating-a-nonlinear-least-squares-model/10706 "2018-05-05T19:50:37Z")

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Related to this PR and this post . We are trying to make a Nonlinear Least Squares model using JuMP, so that the matrices are sparse. From @miles.lubin suggestion, I’m building a model passing the residuals as NLexpressi…

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## [Importing/loading local javascript file with WebIO](https://discourse.julialang.org/t/importing-loading-local-javascript-file-with-webio/9771)

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**Author:** [@AleMorales](https://discourse.julialang.org/u/AleMorales)\
**Replies:** 5\
**Last updated:** [May 4, 2018, 5:54pm UTC](https://discourse.julialang.org/t/importing-loading-local-javascript-file-with-webio/9771 "2018-05-04T17:54:55Z")

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I am building a 3D visualization system for my models based on three.js using WebIO, inspired by the proof of concept here. I have managed to do some basic rendering so far but now I would like to use a local version of t…

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## [Docker API for Julia](https://discourse.julialang.org/t/docker-api-for-julia/10705)

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**Author:** [@lage](https://discourse.julialang.org/u/lage)\
**Replies:** 0\
**Last updated:** [May 4, 2018, 4:08pm UTC](https://discourse.julialang.org/t/docker-api-for-julia/10705 "2018-05-04T16:08:01Z")

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Hello, Does anybody know if there is a Docker API for managing containers in Julia? The only project I’m aware of is Docker.jl \* which is not compatible to Julia 0.6.2. Thanks, André Lage. (\*) I opened this issue: h…

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## [Cholfact on reshape of view of array](https://discourse.julialang.org/t/cholfact-on-reshape-of-view-of-array/10674)

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**Author:** [@lcambier](https://discourse.julialang.org/u/lcambier)\
**Replies:** 2\
**Last updated:** [May 3, 2018, 2:06pm UTC](https://discourse.julialang.org/t/cholfact-on-reshape-of-view-of-array/10674 "2018-05-03T14:06:36Z")

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Hi, I would like to be able to compute the following julia\> A = ones(1000); julia\> B = view(A, 100:199); julia\> C = reshape(B, 10, 10); julia\> F = cholfact!(C) # Obviously this is not SPD :D But I get ERROR: MethodE…

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## [How to insert a IF inside a declaration of a variable JuMP](https://discourse.julialang.org/t/how-to-insert-a-if-inside-a-declaration-of-a-variable-jump/10673)

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**Author:** [@jayce\_ram](https://discourse.julialang.org/u/jayce_ram)\
**Replies:** 5\
**Last updated:** [May 3, 2018, 11:40am UTC](https://discourse.julialang.org/t/how-to-insert-a-if-inside-a-declaration-of-a-variable-jump/10673 "2018-05-03T11:40:06Z")

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In order to avoid the creation of variables that are not really necessary in my problem, I’d like to insert a IF in the declaration of the variables. Like this : @variable(model, x\_prod\[l in localization, inst in inst\_…

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## [Pmap with external command](https://discourse.julialang.org/t/pmap-with-external-command/10676)

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**Author:** [@Olivier\_Merchiers](https://discourse.julialang.org/u/Olivier_Merchiers)\
**Replies:** 0\
**Last updated:** [May 3, 2018, 9:24am UTC](https://discourse.julialang.org/t/pmap-with-external-command/10676 "2018-05-03T09:24:17Z")

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Hello everyone, I’m not sure if this is the right category, so feel free to move it. I have the following issue. I would like to combine pmap with an external c++ code (scuff-em). In order to streamline the workflow I …

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## [Reading a CSV file with an unconventional string for missing values using TextParse](https://discourse.julialang.org/t/reading-a-csv-file-with-an-unconventional-string-for-missing-values-using-textparse/10631)

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**Author:** [@askvorts](https://discourse.julialang.org/u/askvorts)\
**Replies:** 4\
**Last updated:** [May 2, 2018, 8:04pm UTC](https://discourse.julialang.org/t/reading-a-csv-file-with-an-unconventional-string-for-missing-values-using-textparse/10631 "2018-05-02T20:04:32Z")

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I am trying to read a CSV file with two columns (Date, Float64) using TextParse. Unfortunately missing values are coded as “-” in that file. When TextParse encounters one of those “-” one gets the following error message…

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## [Fisher's test p-value results appear to differ from matlab, R](https://discourse.julialang.org/t/fishers-test-p-value-results-appear-to-differ-from-matlab-r/10630)

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**Author:** [@ScottWatkins](https://discourse.julialang.org/u/ScottWatkins)\
**Replies:** 6\
**Last updated:** [May 1, 2018, 4:25pm UTC](https://discourse.julialang.org/t/fishers-test-p-value-results-appear-to-differ-from-matlab-r/10630 "2018-05-01T16:25:48Z")

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Hi, I was using HypothesisTests.jl and noticed minor, but possibly important differences in the p-value estimate between julia and two other packages when using Fisher’s exact test. In this example, matlab and R users …

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## [Importing CSV with missing data](https://discourse.julialang.org/t/importing-csv-with-missing-data/10589)

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**Author:** [@pmarg](https://discourse.julialang.org/u/pmarg)\
**Replies:** 13\
**Last updated:** [April 30, 2018, 5:10pm UTC](https://discourse.julialang.org/t/importing-csv-with-missing-data/10589 "2018-04-30T17:10:31Z")

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Hello everyone, I’m having troubles with reading a CSV with missing data. If a single column has missing values then all the imported columns are of type Missing. For example importing df.csv: "X1","X2" 1, 3 2, 4 , 5 …

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## [Modify a remote object](https://discourse.julialang.org/t/modify-a-remote-object/10612)

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**Author:** [@bbrunaud](https://discourse.julialang.org/u/bbrunaud)\
**Replies:** 3\
**Last updated:** [April 30, 2018, 1:38am UTC](https://discourse.julialang.org/t/modify-a-remote-object/10612 "2018-04-30T01:38:47Z")

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Hello, I would like to send an object to a worker and modify the remote object. The following code did not work as expected. julia\> addprocs(1) 1-element Array{Int64,1}: 2 julia\> n = 1 1 julia\> remotecall\_fetch(()-\>n…

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## [Gurobi 8.0](https://discourse.julialang.org/t/gurobi-8-0/10606)

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**Author:** [@Frank\_Kampas](https://discourse.julialang.org/u/Frank_Kampas)\
**Replies:** 2\
**Last updated:** [April 29, 2018, 3:54pm UTC](https://discourse.julialang.org/t/gurobi-8-0/10606 "2018-04-29T15:54:55Z")

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What’s the process to switch to the new Gurobi release (8.0) ?

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## [Very Slow Compilation for Sensitivity Analysis](https://discourse.julialang.org/t/very-slow-compilation-for-sensitivity-analysis/10598)

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**Author:** [@ckfinite](https://discourse.julialang.org/u/ckfinite)\
**Replies:** 3\
**Last updated:** [April 28, 2018, 8:01pm UTC](https://discourse.julialang.org/t/very-slow-compilation-for-sensitivity-analysis/10598 "2018-04-28T20:01:20Z")

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I’m working on an application that performs optimization of a complex ODE by iteratively optimizing over the linearized system. The optimization works fine, but sensitivity analysis of the ODE has very strange performanc…

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## [A proposal for \`describe\` of a DataFrame](https://discourse.julialang.org/t/a-proposal-for-describe-of-a-dataframe/10254)

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**Author:** [@pdeffebach](https://discourse.julialang.org/u/pdeffebach)\
**Replies:** 17\
**Last updated:** [April 28, 2018, 9:05am UTC](https://discourse.julialang.org/t/a-proposal-for-describe-of-a-dataframe/10254 "2018-04-28T09:05:38Z")

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I am interested in making DataFrames as functional as R and Stata’s ecosystem. So far, I am really impressed with the data munging and processing ecosystem. I think a combination of DataFrames, DataFramesMeta, and Lazy r…

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## [GLM.jl module : 1 test failed](https://discourse.julialang.org/t/glm-jl-module-1-test-failed/10567)

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**Author:** [@hung-q-ngo](https://discourse.julialang.org/u/hung-q-ngo)\
**Replies:** 3\
**Last updated:** [April 28, 2018, 8:05am UTC](https://discourse.julialang.org/t/glm-jl-module-1-test-failed/10567 "2018-04-28T08:05:57Z")

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Hello, any idea what I did wrong here? (I have julia version 0.6.2, and latest GLM.jl package). I was running ~/repos/git/GLM.jl/test$ julia runtests.jl and got WARNING: Method definition ==(Base.Nullable{S}, Base.Nul…

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## [Sampling Multiple samples from NormalInverseGamma distribution](https://discourse.julialang.org/t/sampling-multiple-samples-from-normalinversegamma-distribution/10575)

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**Author:** [@v-i-s-h](https://discourse.julialang.org/u/v-i-s-h)\
**Replies:** 2\
**Last updated:** [April 27, 2018, 4:26pm UTC](https://discourse.julialang.org/t/sampling-multiple-samples-from-normalinversegamma-distribution/10575 "2018-04-27T16:26:25Z")

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Hi, I’m trying to sample multiple samples from a NormalInversaGamma distribution. I was using rand() function with two arguments, but is getting the following error: julia\> using ConjugatePriors julia\> D = ConjugatePri…

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## [\`precision\` of a \`BigFloat\` number returning an \`Int32\` on Windows 10](https://discourse.julialang.org/t/precision-of-a-bigfloat-number-returning-an-int32-on-windows-10/10292)

<div class="topic-metadata">

**Author:** [@Kolaru](https://discourse.julialang.org/u/Kolaru)\
**Replies:** 5\
**Last updated:** [April 27, 2018, 12:00am UTC](https://discourse.julialang.org/t/precision-of-a-bigfloat-number-returning-an-int32-on-windows-10/10292 "2018-04-27T00:00:55Z")

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I recently encountered a strange comportment on my machine : julia\> typeof(precision(2.2)) Int64 julia\> typeof(precision(BigFloat(2.2))) Int32 I tried the same code in JuliaBox and there it returns an Int64 both time, …

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