# Specific Domains

**URL:** https://discourse.julialang.org/c/domain/10.md?page=548

[Latest](https://discourse.julialang.org/latest.md) · [Categories](https://discourse.julialang.org/categories.md) · [Tags](https://discourse.julialang.org/tags.md)

**Page:** 549

---

## [Why Don't Shared Arrays Allow Non-Bit-Types?](https://discourse.julialang.org/t/why-dont-shared-arrays-allow-non-bit-types/6975)

<div class="topic-metadata">

**Author:** [@Juser](https://discourse.julialang.org/u/Juser)\
**Replies:** 5\
**Last updated:** [December 12, 2017, 7:23pm UTC](https://discourse.julialang.org/t/why-dont-shared-arrays-allow-non-bit-types/6975 "2017-12-12T19:23:43Z")

</div>

It would be extremely useful to have shared arrays of non-bit-types. Automatic differentiation, for example, requires functions to accept \<:Real types, and this makes shared arrays difficult to use within function evalu…

---

## [JuMP: Ipopt, ECOS, ErrorMsg: no method matching setvartype](https://discourse.julialang.org/t/jump-ipopt-ecos-errormsg-no-method-matching-setvartype/7705)

<div class="topic-metadata">

**Author:** [@Anton\_Hinneck](https://discourse.julialang.org/u/Anton_Hinneck)\
**Replies:** 3\
**Last updated:** [December 12, 2017, 5:31pm UTC](https://discourse.julialang.org/t/jump-ipopt-ecos-errormsg-no-method-matching-setvartype/7705 "2017-12-12T17:31:08Z")

</div>

Hi, I have been programming a MILP for university. The model is feasible and was already solved using GLPK, CBC, Gurobi and CPLEX. The results are as expected and were carefully examined already. However, I have an issue…

---

## [Knet.jl CNN Tutorial Speed](https://discourse.julialang.org/t/knet-jl-cnn-tutorial-speed/7500)

<div class="topic-metadata">

**Author:** [@rickhg12hs](https://discourse.julialang.org/u/rickhg12hs)\
**Replies:** 3\
**Last updated:** [December 12, 2017, 1:59pm UTC](https://discourse.julialang.org/t/knet-jl-cnn-tutorial-speed/7500 "2017-12-12T13:59:43Z")

</div>

Knet’s tutorial.ipynb trains a CNN with MNIST data. I have no GPU, but my quad-core I7 has been pegged for a day stuck on cnnmodels = \[ copy(train!(wcnn, dtrn)) for epoch=1:100 \];. Is this exceptionally long training t…

---

## [First-class histogram object and plotting in Plots.jl](https://discourse.julialang.org/t/first-class-histogram-object-and-plotting-in-plots-jl/7674)

<div class="topic-metadata">

**Author:** [@Tamas\_Papp](https://discourse.julialang.org/u/Tamas_Papp)\
**Replies:** 2\
**Last updated:** [December 11, 2017, 7:33am UTC](https://discourse.julialang.org/t/first-class-histogram-object-and-plotting-in-plots-jl/7674 "2017-12-11T07:33:22Z")

</div>

I have a dataset with a large number of points, and would like to plot histograms which are costly to calculate. I would prefer if I could save the calculated histogram using JLD2, then load it in a separate script for p…

---

## [Range for core function rand()](https://discourse.julialang.org/t/range-for-core-function-rand/7685)

<div class="topic-metadata">

**Author:** [@zlon](https://discourse.julialang.org/u/zlon)\
**Replies:** 1\
**Last updated:** [December 10, 2017, 10:01pm UTC](https://discourse.julialang.org/t/range-for-core-function-rand/7685 "2017-12-10T22:01:23Z")

</div>

I couldn’t find it in docs. If X=rand(), then X comes from \[0 1\] or \[0 1) or some other variance?

---

## [Set Cache Configuration using CUDAdrv or CUDAnative](https://discourse.julialang.org/t/set-cache-configuration-using-cudadrv-or-cudanative/7675)

<div class="topic-metadata">

**Author:** [@drjoke](https://discourse.julialang.org/u/drjoke)\
**Replies:** 1\
**Last updated:** [December 10, 2017, 5:38pm UTC](https://discourse.julialang.org/t/set-cache-configuration-using-cudadrv-or-cudanative/7675 "2017-12-10T17:38:20Z")

</div>

Similar to cudaFuncSetCacheConfig(fooKernel, cudaFuncCachePreferL1) I cannot find any example on how to do this. Is it possible?

---

## [Deprecated csv prefix](https://discourse.julialang.org/t/deprecated-csv-prefix/7616)

<div class="topic-metadata">

**Author:** [@juliohm](https://discourse.julialang.org/u/juliohm)\
**Replies:** 4\
**Last updated:** [December 8, 2017, 10:22pm UTC](https://discourse.julialang.org/t/deprecated-csv-prefix/7616 "2017-12-08T22:22:19Z")

</div>

Hi, Can you please clarify the newer syntax? csv""" x, y, z 1, 2, 3 """ @csv\_str and the csv"“” syntax are deprecated. Use CSV.read(IOBuffer(…)) from the CSV package instead. Why the csv prefix was deprecated, coul…

---

## [Review of presentation](https://discourse.julialang.org/t/review-of-presentation/7615)

<div class="topic-metadata">

**Author:** [@xiaodai](https://discourse.julialang.org/u/xiaodai)\
**Replies:** 12\
**Last updated:** [December 8, 2017, 9:00pm UTC](https://discourse.julialang.org/t/review-of-presentation/7615 "2017-12-08T21:00:54Z")

</div>

I made this presentation focused on the data ecosystem in Julia. I just wanted to post it here for feedback so I can polish it. Thanks

---

## [Interpolation in constraint](https://discourse.julialang.org/t/interpolation-in-constraint/7325)

<div class="topic-metadata">

**Author:** [@MaximilianJHuber](https://discourse.julialang.org/u/MaximilianJHuber)\
**Replies:** 3\
**Last updated:** [December 7, 2017, 3:59pm UTC](https://discourse.julialang.org/t/interpolation-in-constraint/7325 "2017-12-07T15:59:17Z")

</div>

Hi, I have a conceptional question: I have 10 non-linear constraints for k=k\_1, ..., k\_{10} (that represent a discrete grid of a continuous variable) and 10 coefficients, \\theta = \\theta\_1, ... \\theta\_{10}, that are det…

---

## [Memory corruption bugs in ECOS.jl and SCS.jl](https://discourse.julialang.org/t/memory-corruption-bugs-in-ecos-jl-and-scs-jl/7582)

<div class="topic-metadata">

**Author:** [@miles.lubin](https://discourse.julialang.org/u/miles.lubin)\
**Replies:** 0\
**Last updated:** [December 6, 2017, 10:26pm UTC](https://discourse.julialang.org/t/memory-corruption-bugs-in-ecos-jl-and-scs-jl/7582 "2017-12-06T22:26:50Z")

</div>

We recently discovered and corrected memory corruption bugs in both ECOS.jl and SCS.jl. The wrappers did not properly keep a reference in Julia to the memory passed to the solvers, so if the GC fired at an inopportune t…

---

## [Sorting seems to have some low hanging speed fruit for sorting by single column](https://discourse.julialang.org/t/sorting-seems-to-have-some-low-hanging-speed-fruit-for-sorting-by-single-column/7568)

<div class="topic-metadata">

**Author:** [@xiaodai](https://discourse.julialang.org/u/xiaodai)\
**Replies:** 7\
**Last updated:** [December 6, 2017, 10:21pm UTC](https://discourse.julialang.org/t/sorting-seems-to-have-some-low-hanging-speed-fruit-for-sorting-by-single-column/7568 "2017-12-06T22:21:31Z")

</div>

I was doing some benchmarking of data.table vs DataFrames.jl. Of course, data.table is still way faster on sorting. But I found a low hanging fruit for sorting performance; it could be the backbone of a PR. Here is an MW…

---

## [DifferentialEquations.jl: split differential equation with explicit propagators](https://discourse.julialang.org/t/differentialequations-jl-split-differential-equation-with-explicit-propagators/7572)

<div class="topic-metadata">

**Author:** [@antoine-levitt](https://discourse.julialang.org/u/antoine-levitt)\
**Replies:** 3\
**Last updated:** [December 6, 2017, 7:45pm UTC](https://discourse.julialang.org/t/differentialequations-jl-split-differential-equation-with-explicit-propagators/7572 "2017-12-06T19:45:03Z")

</div>

I have a PDE that is (not exactly but close to) du/dt + v \\cdot du/dx = A(x)u, where x is 2D, u is a vector with two components and A is a 2x2 matrix. The initial data possibly has shocks (discontinuities). Right now I u…

---

## [@parallel for and more complex operations](https://discourse.julialang.org/t/parallel-for-and-more-complex-operations/7562)

<div class="topic-metadata">

**Author:** [@Ferran\_Mazzanti](https://discourse.julialang.org/u/Ferran_Mazzanti)\
**Replies:** 8\
**Last updated:** [December 6, 2017, 6:12pm UTC](https://discourse.julialang.org/t/parallel-for-and-more-complex-operations/7562 "2017-12-06T18:12:38Z")

</div>

Hi, I’m starting to appreciate the benefits and simplicity of @parallel for in my codes… sometimes these really run fast, but I have seen that the operation you can perform on the result of each iteration in the for is …

---

## [Restarting NLP solve from previous infeasible solution](https://discourse.julialang.org/t/restarting-nlp-solve-from-previous-infeasible-solution/7542)

<div class="topic-metadata">

**Author:** [@adowling2](https://discourse.julialang.org/u/adowling2)\
**Replies:** 1\
**Last updated:** [December 6, 2017, 2:25am UTC](https://discourse.julialang.org/t/restarting-nlp-solve-from-previous-infeasible-solution/7542 "2017-12-06T02:25:13Z")

</div>

I am solving a nasty, non-convex NLP. In some instances, Ipopt converges to a point of local infeasibility. For other problems, I observed that restarting Ipopt from such an infeasible solution can sometimes lead to an o…

---

## [Symv producing incorrect results](https://discourse.julialang.org/t/symv-producing-incorrect-results/7548)

<div class="topic-metadata">

**Author:** [@Elrod](https://discourse.julialang.org/u/Elrod)\
**Replies:** 2\
**Last updated:** [December 5, 2017, 10:02pm UTC](https://discourse.julialang.org/t/symv-producing-incorrect-results/7548 "2017-12-05T22:02:56Z")

</div>

Can anyone reproduce the following bug? julia\> A = randn(10,20) |\> X -\> X \* X'; julia\> x = rand(10); julia\> sA = Symmetric(A); julia\> all( A .== sA ) true julia\> (A \* x)' 1×10 RowVector{Float64,Array{Float64,1}}: 1…

---

## [Introducing a new Control Toolbox for Julia with Interactive root locus](https://discourse.julialang.org/t/introducing-a-new-control-toolbox-for-julia-with-interactive-root-locus/7486)

<div class="topic-metadata">

**Author:** [@Ronis\_BR](https://discourse.julialang.org/u/Ronis_BR)\
**Replies:** 13\
**Last updated:** [December 5, 2017, 12:45pm UTC](https://discourse.julialang.org/t/introducing-a-new-control-toolbox-for-julia-with-interactive-root-locus/7486 "2017-12-05T12:45:12Z")

</div>

Hi guys! I finally decided to publish a Control Toolbox we were developing at my institution. I know that there are a few alternatives already coded in Julia, but we wanted something more specific. We wanted that the co…

---

## [Incorrect Bound Error Exception](https://discourse.julialang.org/t/incorrect-bound-error-exception/7525)

<div class="topic-metadata">

**Author:** [@tlagos](https://discourse.julialang.org/u/tlagos)\
**Replies:** 1\
**Last updated:** [December 5, 2017, 12:11pm UTC](https://discourse.julialang.org/t/incorrect-bound-error-exception/7525 "2017-12-05T12:11:24Z")

</div>

Hello, I’m doing a enumeration of solutions in a simulation framework. As an example, I’m consulting if the k-th component in the t-th period was already visited: sum(wx\[k,1:t\])==0 The weird thing is that is throwing…

---

## [Plot(twinx(), ...) creates ylabel on the wrong side of the plot (left instead of ríght)](https://discourse.julialang.org/t/plot-twinx-creates-ylabel-on-the-wrong-side-of-the-plot-left-instead-of-right/7437)

<div class="topic-metadata">

**Author:** [@LotteVictor](https://discourse.julialang.org/u/LotteVictor)\
**Replies:** 3\
**Last updated:** [December 4, 2017, 8:53am UTC](https://discourse.julialang.org/t/plot-twinx-creates-ylabel-on-the-wrong-side-of-the-plot-left-instead-of-right/7437 "2017-12-04T08:53:13Z")

</div>

Hey all! I hope, I’m posting this in the correct category. In my question about visualization (Overlay plot with second plot with second y-axis to the right?) an issue occured that was identified as a bug by @mkborregaar…

---

## [Plots: Past, Present, and Future](https://discourse.julialang.org/t/plots-past-present-and-future/7469)

<div class="topic-metadata">

**Author:** [@tbreloff](https://discourse.julialang.org/u/tbreloff)\
**Replies:** 2\
**Last updated:** [December 3, 2017, 3:57pm UTC](https://discourse.julialang.org/t/plots-past-present-and-future/7469 "2017-12-03T15:57:01Z")

</div>

Hi all. I’ve been very passively monitoring activity in the Julia community the last few months, and I’ve noticed some confusion about Plots/JuliaPlots as well as my role in the community. I’ve been meaning to post som…

---

## [TensorFlow.jl MNIST Tutorial fails.](https://discourse.julialang.org/t/tensorflow-jl-mnist-tutorial-fails/7476)

<div class="topic-metadata">

**Author:** [@rickhg12hs](https://discourse.julialang.org/u/rickhg12hs)\
**Replies:** 0\
**Last updated:** [December 3, 2017, 2:30pm UTC](https://discourse.julialang.org/t/tensorflow-jl-mnist-tutorial-fails/7476 "2017-12-03T14:30:44Z")

</div>

Ref: Github Issue Report Both MNIST tutorials (softmax & CNN) fail with TensorFlow.jl. I’m a ML noob and I’m not sure how to further diagnose the problem. Is this a Tensorflow.jl problem or perhaps a tutorial problem? …

---

## [When shall I use \`BLAS.axpy!\` and when \`muladd\`?](https://discourse.julialang.org/t/when-shall-i-use-blas-axpy-and-when-muladd/7466)

<div class="topic-metadata">

**Author:** [@chobbes](https://discourse.julialang.org/u/chobbes)\
**Replies:** 6\
**Last updated:** [December 3, 2017, 2:22pm UTC](https://discourse.julialang.org/t/when-shall-i-use-blas-axpy-and-when-muladd/7466 "2017-12-03T14:22:03Z")

</div>

Can’t tell much difference between the two. Any insights? Thanks.

---

## [Loading/writing a single element from an array in JLD](https://discourse.julialang.org/t/loading-writing-a-single-element-from-an-array-in-jld/7414)

<div class="topic-metadata">

**Author:** [@Axel\_Gagge](https://discourse.julialang.org/u/Axel_Gagge)\
**Replies:** 3\
**Last updated:** [December 3, 2017, 3:07am UTC](https://discourse.julialang.org/t/loading-writing-a-single-element-from-an-array-in-jld/7414 "2017-12-03T03:07:56Z")

</div>

I want to save and load data with JLD.jl (or HDF5.jl or something) which is is a 1-dimensional array of large elements (themselves large arrays). I want to be able to work with one or a few of the array elements at a tim…

---

## [@parallel constructs](https://discourse.julialang.org/t/parallel-constructs/7460)

<div class="topic-metadata">

**Author:** [@TomConlin](https://discourse.julialang.org/u/TomConlin)\
**Replies:** 4\
**Last updated:** [December 2, 2017, 11:33pm UTC](https://discourse.julialang.org/t/parallel-constructs/7460 "2017-12-02T23:33:30Z")

</div>

Hope this is the appropriate place to put this, if not please feel free to move it. I am wondering if Julia would accept a PR for additional @parallel macros optimized for Lower (and Upper) Triangular Matrices. The b…

---

## [Accurate summation algorithm](https://discourse.julialang.org/t/accurate-summation-algorithm/7163)

<div class="topic-metadata">

**Author:** [@certik](https://discourse.julialang.org/u/certik)\
**Replies:** 34\
**Last updated:** [December 1, 2017, 7:45pm UTC](https://discourse.julialang.org/t/accurate-summation-algorithm/7163 "2017-12-01T19:45:05Z")

</div>

Stefan Karpinski posted an interesting challenge in https://github.com/JuliaLang/julia/issues/24568#issuecomment-344760163: Try to find a summation algorithm whose results are always between (1-1e-14)\*s and (1+1e-14)\*s…

---

## [Simple PDE benchmark](https://discourse.julialang.org/t/simple-pde-benchmark/7430)

<div class="topic-metadata">

**Author:** [@antoine-levitt](https://discourse.julialang.org/u/antoine-levitt)\
**Replies:** 14\
**Last updated:** [December 1, 2017, 5:53pm UTC](https://discourse.julialang.org/t/simple-pde-benchmark/7430 "2017-12-01T17:53:19Z")

</div>

Hi, I made a simple benchmark to try and convince colleagues to switch to Julia. It might be of interest to people, so here it is : https://github.com/antoine-levitt/benchmark\_heat. It’s the most simple PDE code I could…

---

## [(Integrated) autocorrelation time](https://discourse.julialang.org/t/integrated-autocorrelation-time/7403)

<div class="topic-metadata">

**Author:** [@Sleort](https://discourse.julialang.org/u/Sleort)\
**Replies:** 6\
**Last updated:** [December 1, 2017, 3:34am UTC](https://discourse.julialang.org/t/integrated-autocorrelation-time/7403 "2017-12-01T03:34:36Z")

</div>

I could not find any (integrated) autocorrelation time estimator in the basic statistics packages\*, so I made a crude implementation myself based on StatsBase.autocor and the tips given in http://www.stat.unc.edu/faculty…

---

## [Force a gradient value at a degenerate point](https://discourse.julialang.org/t/force-a-gradient-value-at-a-degenerate-point/7418)

<div class="topic-metadata">

**Author:** [@vepiteski](https://discourse.julialang.org/u/vepiteski)\
**Replies:** 1\
**Last updated:** [December 1, 2017, 1:34am UTC](https://discourse.julialang.org/t/force-a-gradient-value-at-a-degenerate-point/7418 "2017-12-01T01:34:55Z")

</div>

I wish to implement Wolfe’s example x0 = \[0; 0.25; 0.0\] lb = \[0.0; 0.0; 0.0\] ub = \[Inf; Inf; 2.0\] @variable(nlp, lb\[i\] \<= x\[i = 1:3\] \<= ub\[i\], start = x0\[i\]) @NLobjective( nlp, Min, 4/3\*(x\[1\]^2 - x\[1\] \* x…

---

## [NLopt stopval and termination criteria](https://discourse.julialang.org/t/nlopt-stopval-and-termination-criteria/7333)

<div class="topic-metadata">

**Author:** [@ivborissov](https://discourse.julialang.org/u/ivborissov)\
**Replies:** 3\
**Last updated:** [November 30, 2017, 3:24pm UTC](https://discourse.julialang.org/t/nlopt-stopval-and-termination-criteria/7333 "2017-11-30T15:24:39Z")

</div>

Hi, I am solving optimization problems like find max x1 in \[a1,b1\] : f(x1,x2,x3...)\<=0 plus I know that at initial point f(a1,a2,a3...)\<=0. Sometimes my model f (based on experimental data) isn’t sensitive to x1 (like …

---

## [Using Math Functions Inside CUDA Kernel](https://discourse.julialang.org/t/using-math-functions-inside-cuda-kernel/7411)

<div class="topic-metadata">

**Author:** [@drjoke](https://discourse.julialang.org/u/drjoke)\
**Replies:** 1\
**Last updated:** [November 30, 2017, 2:15pm UTC](https://discourse.julialang.org/t/using-math-functions-inside-cuda-kernel/7411 "2017-11-30T14:15:31Z")

</div>

using CUDAdrv, CUDAnative function kernel\_a(a) i = (blockIdx().x-1) \* blockDim().x + threadIdx().x a\[i\] = tanh(a\[i\]) return nothing end dev = CuDevice(0) ctx = CuContext(dev) len = 100 a = rand(Float32, len…

---

## [Maybe an area the Julia folks may want to explore](https://discourse.julialang.org/t/maybe-an-area-the-julia-folks-may-want-to-explore/7410)

<div class="topic-metadata">

**Author:** [@Frank\_Applin](https://discourse.julialang.org/u/Frank_Applin)\
**Replies:** 0\
**Last updated:** [November 30, 2017, 1:47pm UTC](https://discourse.julialang.org/t/maybe-an-area-the-julia-folks-may-want-to-explore/7410 "2017-11-30T13:47:30Z")

</div>

Developers use 750 Raspberry Pi boards as supercomputing testbed

[Previous page](https://discourse.julialang.org/c/domain/10.md?page=547)

[Next page](https://discourse.julialang.org/c/domain/10.md?page=549)