# Specific Domains

**URL:** https://discourse.julialang.org/c/domain/10.md?no_subcategories=false&page=319

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**Page:** 320

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## [Custom rrule for Feedback Alignment](https://discourse.julialang.org/t/custom-rrule-for-feedback-alignment/72159)

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**Author:** [@Rasmus\_Hoier](https://discourse.julialang.org/u/Rasmus_Hoier)\
**Replies:** 2\
**Last updated:** [November 27, 2021, 8:10pm UTC](https://discourse.julialang.org/t/custom-rrule-for-feedback-alignment/72159 "2021-11-27T20:10:36Z")

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Hi, I am trying to use a custom rrule to implement Feedback Alignment learning (which is just like BP except that the error signals are propagated backwards using random feedback weights B, which is supposed to be more …

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## [Complex step differentiation method explained](https://discourse.julialang.org/t/complex-step-differentiation-method-explained/14647)

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**Author:** [@jlapeyre](https://discourse.julialang.org/u/jlapeyre)\
**Replies:** 8\
**Last updated:** [November 27, 2021, 11:33am UTC](https://discourse.julialang.org/t/complex-step-differentiation-method-explained/14647 "2021-11-27T11:33:20Z")

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I wrote a brief post explaining the “complex step method” that was the first topic in Nick Higham’s JuliaCon 2018 talk. (Using Julia for demonstrations, of course !)

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## [Is there a lazy way to create another variable based on the dimensionality of one variable?](https://discourse.julialang.org/t/is-there-a-lazy-way-to-create-another-variable-based-on-the-dimensionality-of-one-variable/72153)

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**Author:** [@iiitr](https://discourse.julialang.org/u/iiitr)\
**Replies:** 1\
**Last updated:** [November 27, 2021, 8:12am UTC](https://discourse.julialang.org/t/is-there-a-lazy-way-to-create-another-variable-based-on-the-dimensionality-of-one-variable/72153 "2021-11-27T08:12:07Z")

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Hi all, There are times when I need to create another variable based on the shape of one variable. Since, I don’t know the dimension of the variable. Therefore, I usually write a lot of if-elseif-else-end blocks to dete…

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## [JuMPChance can not be added](https://discourse.julialang.org/t/jumpchance-can-not-be-added/72151)

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**Author:** [@Xuekui\_wang](https://discourse.julialang.org/u/Xuekui_wang)\
**Replies:** 2\
**Last updated:** [November 27, 2021, 7:22am UTC](https://discourse.julialang.org/t/jumpchance-can-not-be-added/72151 "2021-11-27T07:22:51Z")

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When I add JuMPChance, there are some errors: (@v1.6) pkg\> add JuMPChance Resolving package versions... ERROR: Unsatisfiable requirements detected for package JuMP \[4076af6c\]: JuMP \[4076af6c\] log: ├─possible versio…

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## [Relaxation of MIP to LP, getdual, CPLEX](https://discourse.julialang.org/t/relaxation-of-mip-to-lp-getdual-cplex/1935)

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**Author:** [@spuschel](https://discourse.julialang.org/u/spuschel)\
**Replies:** 4\
**Last updated:** [November 27, 2021, 3:44am UTC](https://discourse.julialang.org/t/relaxation-of-mip-to-lp-getdual-cplex/1935 "2021-11-27T03:44:01Z")

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Hi guys. I’ve been reading this forum and the previous one (on Google) and I can’t seem to find an answer (although there are close examples) to my problem. It is about getting dual values out of an MIP. The standard w…

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## [Run Scotland's Public Finances in Julia](https://discourse.julialang.org/t/run-scotlands-public-finances-in-julia/72105)

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**Author:** [@grahamstark](https://discourse.julialang.org/u/grahamstark)\
**Replies:** 0\
**Last updated:** [November 26, 2021, 11:02am UTC](https://discourse.julialang.org/t/run-scotlands-public-finances-in-julia/72105 "2021-11-26T11:02:27Z")

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If you’re interested in public economics or policy research generally this might interest you: https://stb.virtual-worlds.scot/scotbudg/ it’s a front-end to a microsimulation of the fiscal system of Scotland. It lets y…

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## [SVM Errors With Grid Search](https://discourse.julialang.org/t/svm-errors-with-grid-search/71954)

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**Author:** [@Rahul](https://discourse.julialang.org/u/Rahul)\
**Replies:** 24\
**Last updated:** [November 26, 2021, 8:31am UTC](https://discourse.julialang.org/t/svm-errors-with-grid-search/71954 "2021-11-26T08:31:36Z")

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I am trying to perform Grid Search CV with SVM as follows: SVMClassifier = @load SVMClassifier pkg=ScikitLearn svm\_model = SVMClassifier() r\_svm = range(svm\_model, :C, values=\[0.25, 0.5, 1\]) self\_tuning\_svm = TunedMode…

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## [Integrating MathOptInterface into an industry-scale project (e.g. constraint management)](https://discourse.julialang.org/t/integrating-mathoptinterface-into-an-industry-scale-project-e-g-constraint-management/71943)

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**Author:** [@pboes](https://discourse.julialang.org/u/pboes)\
**Replies:** 9\
**Last updated:** [November 25, 2021, 11:15pm UTC](https://discourse.julialang.org/t/integrating-mathoptinterface-into-an-industry-scale-project-e-g-constraint-management/71943 "2021-11-25T23:15:31Z")

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Hi, I have been tasked by my employer to think about a general “Operations Research Framework” that guides future operations research projects, both at the level of project management (how to organise this in an agile w…

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## [CuDynamicSharedArray error](https://discourse.julialang.org/t/cudynamicsharedarray-error/72063)

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**Author:** [@Jakub\_Mitura](https://discourse.julialang.org/u/Jakub_Mitura)\
**Replies:** 2\
**Last updated:** [November 25, 2021, 1:58pm UTC](https://discourse.julialang.org/t/cudynamicsharedarray-error/72063 "2021-11-25T13:58:53Z")

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Hello I am running extremely simple kernel as shown below and get and error pointing to CuDynamicSharedArray using CUDA ff = CUDA.zeros(3) function gggg(ff) shmemblockDataa = @cuDynamicSharedMem(Float32,(1,2)) r…

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## [Flux.jl simple classification, add to Model Zoo?](https://discourse.julialang.org/t/flux-jl-simple-classification-add-to-model-zoo/71934)

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**Author:** [@TheLateKronos](https://discourse.julialang.org/u/TheLateKronos)\
**Replies:** 0\
**Last updated:** [November 23, 2021, 10:38am UTC](https://discourse.julialang.org/t/flux-jl-simple-classification-add-to-model-zoo/71934 "2021-11-23T10:38:27Z")

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I just got a simple classification example working with Flux.jl. I was originally looking for something like it, but did not find anything. I have tried to make comments along the way on the level I would have needed yes…

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## [Plot a diagonal 1:1 line in a marginalkde plot](https://discourse.julialang.org/t/plot-a-diagonal-1-1-line-in-a-marginalkde-plot/72036)

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**Author:** [@rio](https://discourse.julialang.org/u/rio)\
**Replies:** 3\
**Last updated:** [November 25, 2021, 9:34am UTC](https://discourse.julialang.org/t/plot-a-diagonal-1-1-line-in-a-marginalkde-plot/72036 "2021-11-25T09:34:24Z")

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Hi, I am trying to add a diagonal 1:1 line to a marginalkde plot. I found that there is Plots.abline! which draws a straight line in the form of ax+b respecting axis limits of the plot. However, my attempt below draws t…

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## [Triton: GPU Programming for Neural Networks](https://discourse.julialang.org/t/triton-gpu-programming-for-neural-networks/72033)

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**Author:** [@stemann](https://discourse.julialang.org/u/stemann)\
**Replies:** 2\
**Last updated:** [November 25, 2021, 9:06am UTC](https://discourse.julialang.org/t/triton-gpu-programming-for-neural-networks/72033 "2021-11-25T09:06:42Z")

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Any thoughts on OpenAI’s Triton? @maleadt ?

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## [Distinct color for missing values in colorbar](https://discourse.julialang.org/t/distinct-color-for-missing-values-in-colorbar/71927)

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**Author:** [@adigitoleo](https://discourse.julialang.org/u/adigitoleo)\
**Replies:** 4\
**Last updated:** [November 24, 2021, 11:46pm UTC](https://discourse.julialang.org/t/distinct-color-for-missing-values-in-colorbar/71927 "2021-11-24T23:46:01Z")

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I am wondering how to handle missing values in a colorbar. For my specific use case, I want to create a scatter plot where the data points are colored according to a third vector of values which may contain missing. Bef…

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## [Defining variable model as x != 0 in JuMP](https://discourse.julialang.org/t/defining-variable-model-as-x-0-in-jump/71162)

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**Author:** [@sbacelar](https://discourse.julialang.org/u/sbacelar)\
**Replies:** 16\
**Last updated:** [November 24, 2021, 4:44pm UTC](https://discourse.julialang.org/t/defining-variable-model-as-x-0-in-jump/71162 "2021-11-24T16:44:40Z")

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I am trying to run my first example of optimization using JuMP. I have a problem with the definition of the values of x. I want to do x != 0 but it gives me an error. It only works for x \>= 0 or x \<= 0. using JuMP im…

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## [Flexible workflow for altering the equations of a dynamical system / diffeq](https://discourse.julialang.org/t/flexible-workflow-for-altering-the-equations-of-a-dynamical-system-diffeq/71390)

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**Author:** [@Datseris](https://discourse.julialang.org/u/Datseris)\
**Replies:** 12\
**Last updated:** [November 24, 2021, 2:54pm UTC](https://discourse.julialang.org/t/flexible-workflow-for-altering-the-equations-of-a-dynamical-system-diffeq/71390 "2021-11-24T14:54:41Z")

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Hi all, kind of organizational equation. I have a dynamical system whose equations I change frequently. I add and remove different dynamical components and connections. I’m in a pretty exploratory stage. It becomes real…

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## [JuMP @constraint with sparse matrix](https://discourse.julialang.org/t/jump-constraint-with-sparse-matrix/71940)

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**Author:** [@Thomas](https://discourse.julialang.org/u/Thomas)\
**Replies:** 4\
**Last updated:** [November 24, 2021, 9:49am UTC](https://discourse.julialang.org/t/jump-constraint-with-sparse-matrix/71940 "2021-11-24T09:49:46Z")

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I want to create PSD constraints with a sparse matrix of AffExpr as in the snippet below (rawdata is a Vector of tuples of the form (I, J, Va, Vs) containing row-col-values information) model = let println("Construc…

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## [Illegal memory access problem CUDA](https://discourse.julialang.org/t/illegal-memory-access-problem-cuda/71836)

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**Author:** [@Jakub\_Mitura](https://discourse.julialang.org/u/Jakub_Mitura)\
**Replies:** 8\
**Last updated:** [November 24, 2021, 7:22am UTC](https://discourse.julialang.org/t/illegal-memory-access-problem-cuda/71836 "2021-11-24T07:22:11Z")

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I am creating some dynamic shared memory boolean arrays in kernel, and it give me consistently ERROR: LoadError: CUDA error: an illegal memory access was encountered (code 700, ERROR\_ILLEGAL\_ADDRESS) Stacktrace: \[1\] t…

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## [Packages for kinematic trees?](https://discourse.julialang.org/t/packages-for-kinematic-trees/55963)

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**Author:** [@airpmb](https://discourse.julialang.org/u/airpmb)\
**Replies:** 3\
**Last updated:** [November 24, 2021, 3:34am UTC](https://discourse.julialang.org/t/packages-for-kinematic-trees/55963 "2021-11-24T03:34:58Z")

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tl;dr: Any good packages for defining trees of named homogeneous transforms? I have a use case and wonder if someone here might help accelerate my search for existing solutions that I can adopt or build upon. Basically …

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## [Implementing the Social Force Model from Helbing 1995](https://discourse.julialang.org/t/implementing-the-social-force-model-from-helbing-1995/71960)

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**Author:** [@jacobusmmsmit](https://discourse.julialang.org/u/jacobusmmsmit)\
**Replies:** 12\
**Last updated:** [November 23, 2021, 10:54pm UTC](https://discourse.julialang.org/t/implementing-the-social-force-model-from-helbing-1995/71960 "2021-11-23T22:54:45Z")

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Hey everyone, I’m trying to implement the social force model for pedestrian dynamics, which models pedestrians using physics. I’m not sure what the best course of action is, specifically in terms of which packages I coul…

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## [Automatic Creation of a Grid of Tuning Parameters](https://discourse.julialang.org/t/automatic-creation-of-a-grid-of-tuning-parameters/71902)

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**Author:** [@Rahul](https://discourse.julialang.org/u/Rahul)\
**Replies:** 4\
**Last updated:** [November 23, 2021, 9:10pm UTC](https://discourse.julialang.org/t/automatic-creation-of-a-grid-of-tuning-parameters/71902 "2021-11-23T21:10:17Z")

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Currently, in R’s caret package if we do something like this: fitControl \<- trainControl(method = "repeatedcv", number=10,repeats=5) model\_rf = train(responder~ ., data=trainData, method='rf',trControl=fitControl) a gr…

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## [Heatmap where x-labels and y-labels are strings](https://discourse.julialang.org/t/heatmap-where-x-labels-and-y-labels-are-strings/71963)

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**Author:** [@Rahul](https://discourse.julialang.org/u/Rahul)\
**Replies:** 2\
**Last updated:** [November 23, 2021, 8:28pm UTC](https://discourse.julialang.org/t/heatmap-where-x-labels-and-y-labels-are-strings/71963 "2021-11-23T20:28:06Z")

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Could any one please help me with plotting a heatmap when x-axis and y-axis are strings. For example, the following code would work: using CairoMakie xs = 1:5 ys = 1:10 zs = \[rand(1)\[1\] for x in xs, y in ys\] heatmap(x…

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## [Convert ILP variables to strict integer values in JuMP](https://discourse.julialang.org/t/convert-ilp-variables-to-strict-integer-values-in-jump/71957)

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**Author:** [@filchristou](https://discourse.julialang.org/u/filchristou)\
**Replies:** 1\
**Last updated:** [November 23, 2021, 7:50pm UTC](https://discourse.julialang.org/t/convert-ilp-variables-to-strict-integer-values-in-jump/71957 "2021-11-23T19:50:01Z")

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It has often happened that after solving a MILP, my integer or binary variables are getting a value something like 4.237436454375536e-11 or 1.0000000000008162 or even 4.0. In other words even though a variable is meant t…

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## [ParallelStencil for Vector Fields](https://discourse.julialang.org/t/parallelstencil-for-vector-fields/70997)

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**Author:** [@gerhardu](https://discourse.julialang.org/u/gerhardu)\
**Replies:** 5\
**Last updated:** [November 23, 2021, 6:04pm UTC](https://discourse.julialang.org/t/parallelstencil-for-vector-fields/70997 "2021-11-23T18:04:11Z")

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Hello, I am trying to use ParallelStencil to solve a diffeq on a lattice, where at each lattice site I have an Array (StaticArray) instead of a float. E.g A vector field on a 3D domain. But @init\_parallel\_stencil works…

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## [JuliaHPC Meeting](https://discourse.julialang.org/t/juliahpc-meeting/49093)

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**Author:** [@simonbyrne](https://discourse.julialang.org/u/simonbyrne)\
**Replies:** 10\
**Last updated:** [November 23, 2021, 3:07pm UTC](https://discourse.julialang.org/t/juliahpc-meeting/49093 "2021-11-23T15:07:11Z")

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Several of us have started a roughly-monthly Julia on HPC-related discussion. The next one is to be held tomorrow (for me at least, probably today for almost everyone else): 18:00 UTC (2pm US Eastern), Tuesday October 2…

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## [Xticks spacing changes when decorations are hidden](https://discourse.julialang.org/t/xticks-spacing-changes-when-decorations-are-hidden/71937)

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**Author:** [@HenriDeh](https://discourse.julialang.org/u/HenriDeh)\
**Replies:** 2\
**Last updated:** [November 23, 2021, 2:57pm UTC](https://discourse.julialang.org/t/xticks-spacing-changes-when-decorations-are-hidden/71937 "2021-11-23T14:57:50Z")

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Helloo, I made a MWE that emulates the kind of problem I have: begin f = Figure() gl = GridLayout() f.layout\[1,1\] = gl for i in 1:2, j in 1:2 gl\[i,j\] = a = Axis(f) for (i,data…

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## [Flux/Zygote: Gradient with respect to inputs and implicit parameters (in 2021)](https://discourse.julialang.org/t/flux-zygote-gradient-with-respect-to-inputs-and-implicit-parameters-in-2021/71931)

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**Author:** [@manuelbb-upb](https://discourse.julialang.org/u/manuelbb-upb)\
**Replies:** 1\
**Last updated:** [November 23, 2021, 12:28pm UTC](https://discourse.julialang.org/t/flux-zygote-gradient-with-respect-to-inputs-and-implicit-parameters-in-2021/71931 "2021-11-23T12:28:14Z")

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Hello all, I have struggled a bit to get the gradient(s) of a loss with a Zygote model both with respect to the model parameters and to the model input. Is it even sensible to do this in one pass? Consider this simple…

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## [Minimisation of a Bolza form loss function in DiffEqFlux framework](https://discourse.julialang.org/t/minimisation-of-a-bolza-form-loss-function-in-diffeqflux-framework/71920)

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**Author:** [@nhcho91](https://discourse.julialang.org/u/nhcho91)\
**Replies:** 3\
**Last updated:** [November 23, 2021, 8:07am UTC](https://discourse.julialang.org/t/minimisation-of-a-bolza-form-loss-function-in-diffeqflux-framework/71920 "2021-11-23T08:07:19Z")

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Brief Summary Problem at hand: minimise J \\left( p \\right) = \\phi \\left( x \\left(t\_{f} \\right) \\right) + \\int\_{t\_{0}}^{t\_{f}} L \\left( \\tau, x\\left(\\tau\\right), p \\right) d\\tau + R\\left( p \\right) subject to \\dot{x}…

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## [Julia package to calculate coverage and depth from sam/bam files](https://discourse.julialang.org/t/julia-package-to-calculate-coverage-and-depth-from-sam-bam-files/71888)

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**Author:** [@Lamma](https://discourse.julialang.org/u/Lamma)\
**Replies:** 4\
**Last updated:** [November 23, 2021, 7:42am UTC](https://discourse.julialang.org/t/julia-package-to-calculate-coverage-and-depth-from-sam-bam-files/71888 "2021-11-23T07:42:27Z")

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Hi there, I am wanting to generate coverage and depth statistic for some sam/bam files I have and was wondering if Julia has a package that can do this for me?

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## [Read optimization model files into Julia](https://discourse.julialang.org/t/read-optimization-model-files-into-julia/71851)

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**Author:** [@ZHEN\_LIN](https://discourse.julialang.org/u/ZHEN_LIN)\
**Replies:** 7\
**Last updated:** [November 23, 2021, 12:23am UTC](https://discourse.julialang.org/t/read-optimization-model-files-into-julia/71851 "2021-11-23T00:23:40Z")

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I would like to read into Julia some optimization models like the one given in the link below http://qplib.zib.de/QPLIB\_0067.html This is a quadratic optimization problem. It looks like it has formats including gms, lp…

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## [PDEsystems has version conflict?](https://discourse.julialang.org/t/pdesystems-has-version-conflict/71871)

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**Author:** [@Goosee](https://discourse.julialang.org/u/Goosee)\
**Replies:** 17\
**Last updated:** [November 22, 2021, 11:04pm UTC](https://discourse.julialang.org/t/pdesystems-has-version-conflict/71871 "2021-11-22T23:04:43Z")

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I am new to Julia. I installed today the latest version of Julia, Atom and Juno and the packages to run the examples on the NeuralPDE.jl website. I cannot run any command from the package ModelingToolkit that uses “PDESy…

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