# Latest

**URL:** https://discourse.julialang.org/latest.md?page=1974

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

**Page:** 1975

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## [Subsetting uninitialized arrays](https://discourse.julialang.org/t/subsetting-uninitialized-arrays/25449)

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**Author:** [@bkamins](https://discourse.julialang.org/u/bkamins)\
**Replies:** 7\
**Last updated:** [June 21, 2019, 10:01am UTC](https://discourse.julialang.org/t/subsetting-uninitialized-arrays/25449 "2019-06-21T10:01:12Z")

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You can subset an uninitialized vector, e.g.: julia\> v = Vector{Any}(undef, 4) 4-element Array{Any,1}: #undef #undef #undef #undef julia\> v\[:\] 4-element Array{Any,1}: #undef #undef #undef #undef But not a matr…

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## [Montecarlo DAE](https://discourse.julialang.org/t/montecarlo-dae/25497)

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**Author:** [@alewolf](https://discourse.julialang.org/u/alewolf)\
**Replies:** 4\
**Last updated:** [June 21, 2019, 7:21am UTC](https://discourse.julialang.org/t/montecarlo-dae/25497 "2019-06-21T07:21:54Z")

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Hi everyone - I am having a little problem defining a montecarlo DAE problem with varying parameters - Any help would be appreciated. Here is toy example, comparinng standard correct solution and montecarlo results. …

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## [Towards a common Manifold Framework / Package](https://discourse.julialang.org/t/towards-a-common-manifold-framework-package/24910)

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**Author:** [@kellertuer](https://discourse.julialang.org/u/kellertuer)\
**Replies:** 10\
**Last updated:** [June 21, 2019, 7:13am UTC](https://discourse.julialang.org/t/towards-a-common-manifold-framework-package/24910 "2019-06-21T07:13:29Z")

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Continuing the discussion from \[ANN\] Manopt.jl I would like to collect Ideas and approaches towards a common package that should be the base for “Things on manifolds”: Solving optimization problems (disclaimer, I am deve…

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## [What happened to \`T?\`](https://discourse.julialang.org/t/what-happened-to-t/25480)

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**Author:** [@gdkrmr](https://discourse.julialang.org/u/gdkrmr)\
**Replies:** 19\
**Last updated:** [June 21, 2019, 5:06am UTC](https://discourse.julialang.org/t/what-happened-to-t/25480 "2019-06-21T05:06:51Z")

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If memory serves me, once upon a time there was a proposal to simplify syntax for missing values: T? == Union{T, Missing} Currently I have to handle a lot of missing values and find the extra typing quite annoying. I…

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## [Testing Unexported functions](https://discourse.julialang.org/t/testing-unexported-functions/25510)

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**Author:** [@Alec\_Loudenback](https://discourse.julialang.org/u/Alec_Loudenback)\
**Replies:** 1\
**Last updated:** [June 21, 2019, 4:12am UTC](https://discourse.julialang.org/t/testing-unexported-functions/25510 "2019-06-21T04:12:28Z")

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If I have a function in a package that I am working on, how do perform unit testing on a function that I don’t want to export? When I try to test my\_unexported\_function via pkg\> test I get the error UndefVarError: my…

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## [Help me get rid of extra allocations in this generic batching iterator](https://discourse.julialang.org/t/help-me-get-rid-of-extra-allocations-in-this-generic-batching-iterator/25061)

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**Author:** [@Roger-luo](https://discourse.julialang.org/u/Roger-luo)\
**Replies:** 3\
**Last updated:** [June 21, 2019, 12:21am UTC](https://discourse.julialang.org/t/help-me-get-rid-of-extra-allocations-in-this-generic-batching-iterator/25061 "2019-06-21T00:21:59Z")

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I’m trying to make the routines in BatchedRoutines more generic, so I could wrap other BLAS routines to use pointer offsets easier. However, when I wrap the iteration to a function, the batched\_gemm routine become type u…

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## [Converting String to DataType](https://discourse.julialang.org/t/converting-string-to-datatype/25504)

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**Author:** [@dataSurfer](https://discourse.julialang.org/u/dataSurfer)\
**Replies:** 3\
**Last updated:** [June 20, 2019, 11:46pm UTC](https://discourse.julialang.org/t/converting-string-to-datatype/25504 "2019-06-20T23:46:42Z")

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I’m using Julia v1.2 rc1 and I’d like to be able to convert a string to a data type but eval(Symbol("SomeComplexType")) isn’t doing it for types that are not basic. For instance this eval(Symbol("Float64")) returns Flo…

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## [Enforcing higher-order type parameter constraints](https://discourse.julialang.org/t/enforcing-higher-order-type-parameter-constraints/25435)

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**Author:** [@simsurace](https://discourse.julialang.org/u/simsurace)\
**Replies:** 13\
**Last updated:** [June 20, 2019, 11:11pm UTC](https://discourse.julialang.org/t/enforcing-higher-order-type-parameter-constraints/25435 "2019-06-20T23:11:24Z")

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One design pattern I keep stumbling upon is that I want to generate parametric types based on existing parametric types, but with certain constraints among parameters, such that inappropriate combinations are prevented f…

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## [Flux ready for a beginner deep learning project?](https://discourse.julialang.org/t/flux-ready-for-a-beginner-deep-learning-project/9262)

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**Author:** [@datnamer](https://discourse.julialang.org/u/datnamer)\
**Replies:** 31\
**Last updated:** [June 20, 2019, 10:59pm UTC](https://discourse.julialang.org/t/flux-ready-for-a-beginner-deep-learning-project/9262 "2019-06-20T22:59:05Z")

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Hi, I’m about to embark on a client facing Deep learning project where I’d need to get up to speed on some basic DL things and then start a research project within a couple of weeks or so. (they are aware of my curren…

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## [Generalizing Dot Syntax to Broadcast Operators for Arbitrary Types](https://discourse.julialang.org/t/generalizing-dot-syntax-to-broadcast-operators-for-arbitrary-types/25459)

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**Author:** [@SEA](https://discourse.julialang.org/u/SEA)\
**Replies:** 3\
**Last updated:** [June 20, 2019, 9:07pm UTC](https://discourse.julialang.org/t/generalizing-dot-syntax-to-broadcast-operators-for-arbitrary-types/25459 "2019-06-20T21:07:43Z")

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I am trying to make the dot syntax for broadcasting work for a type which I defined. As an example, mutable struct A a b end function broadcast!(f, dest::A, x::A, y::A) dest.a = f(x.a, y.a) dest.b = f(x.b, y.b) …

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## [Error: cannot set terminal process group (-1)](https://discourse.julialang.org/t/error-cannot-set-terminal-process-group-1/25496)

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**Author:** [@comaldave](https://discourse.julialang.org/u/comaldave)\
**Replies:** 0\
**Last updated:** [June 20, 2019, 7:50pm UTC](https://discourse.julialang.org/t/error-cannot-set-terminal-process-group-1/25496 "2019-06-20T19:50:49Z")

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First time user, starting up for the first time, received some error messages, everything seems to be running fine otherwise. \[david@localhost JuliaPro-1.1.1.1\]$ ./Launch\_JuliaPro bash: cannot set terminal pro…

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## [Using PARTR in Julia 1.2?](https://discourse.julialang.org/t/using-partr-in-julia-1-2/25485)

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**Author:** [@oschulz](https://discourse.julialang.org/u/oschulz)\
**Replies:** 7\
**Last updated:** [June 20, 2019, 7:08pm UTC](https://discourse.julialang.org/t/using-partr-in-julia-1-2/25485 "2019-06-20T19:08:44Z")

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Hi, from what I understand, PARTR (resp. parts of what it will become) will be part of Julia 1.2. I’m keen to try it out, if possible, by my attempts at starting tasks within an @threads loop have failed, the tasks alwa…

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## [Float32 function return and Cuda](https://discourse.julialang.org/t/float32-function-return-and-cuda/25489)

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**Author:** [@wiktorkujawa](https://discourse.julialang.org/u/wiktorkujawa)\
**Replies:** 3\
**Last updated:** [June 20, 2019, 7:06pm UTC](https://discourse.julialang.org/t/float32-function-return-and-cuda/25489 "2019-06-20T19:06:11Z")

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I have GPU(GTX 1050) that performance for Float32 compared to Float64 is about 32 times better, so I should use Float32 values. I have function that return values in format of Float64(or Tuple of Float64). Function looks…

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## [Can't pop/delteat elements in loop](https://discourse.julialang.org/t/cant-pop-delteat-elements-in-loop/25462)

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**Author:** [@wiktorkujawa](https://discourse.julialang.org/u/wiktorkujawa)\
**Replies:** 4\
**Last updated:** [June 20, 2019, 6:28pm UTC](https://discourse.julialang.org/t/cant-pop-delteat-elements-in-loop/25462 "2019-06-20T18:28:18Z")

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I can pop/deleteat only last element in my program. Here’s the code(it uses CImGui library): for i=1:length(S) CImGui.PushID(i-1) CImGui.Text("Line nr $i: $(S\[i\]) \\n") CImGui.SameLine() CImGui.Button…

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## [More elegant way to get the \`UnionAll\` type from an instance?](https://discourse.julialang.org/t/more-elegant-way-to-get-the-unionall-type-from-an-instance/22439)

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**Author:** [@singularitti](https://discourse.julialang.org/u/singularitti)\
**Replies:** 4\
**Last updated:** [June 20, 2019, 6:24pm UTC](https://discourse.julialang.org/t/more-elegant-way-to-get-the-unionall-type-from-an-instance/22439 "2019-06-20T18:24:24Z")

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I have a UnionAll type MyVec: julia\> struct MyVec{a,A \<: AbstractVector} data::A function MyVec{a,A}(data) where {a,A} new(data) end end julia\> x = MyVec{:x, Vecto…

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## [Pmap over data frame](https://discourse.julialang.org/t/pmap-over-data-frame/25432)

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**Author:** [@abx](https://discourse.julialang.org/u/abx)\
**Replies:** 1\
**Last updated:** [June 20, 2019, 6:18pm UTC](https://discourse.julialang.org/t/pmap-over-data-frame/25432 "2019-06-20T18:18:13Z")

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I am trying to pmap a function over a DataFrame, probably I am missing something really obvious. As per the example below, I would each DataFrameRow to be an element of the pmap, and each column value of the DataFrameRo…

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## [Debugging strange allocations](https://discourse.julialang.org/t/debugging-strange-allocations/25488)

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**Author:** [@jw3126](https://discourse.julialang.org/u/jw3126)\
**Replies:** 5\
**Last updated:** [June 20, 2019, 4:19pm UTC](https://discourse.julialang.org/t/debugging-strange-allocations/25488 "2019-06-20T16:19:11Z")

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Motivation When optimizing julia code, my first step is usually to make sure the compiler infers everything. There are great tools like @code\_warntype and Cthulhu, that allow to diagnose inference problems in a systemati…

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## [User-defined Variadic Parametric Types](https://discourse.julialang.org/t/user-defined-variadic-parametric-types/25487)

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**Author:** [@cshenton](https://discourse.julialang.org/u/cshenton)\
**Replies:** 4\
**Last updated:** [June 20, 2019, 4:09pm UTC](https://discourse.julialang.org/t/user-defined-variadic-parametric-types/25487 "2019-06-20T16:09:29Z")

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In Base, Tuple can have variadic (0 or more) type arguments. Is there a way to achieve this for a user defined type? I want to represent something like a strongly typed reference to a single database row. Where the str…

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## [About Julia and Lisp](https://discourse.julialang.org/t/about-julia-and-lisp/25119)

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**Author:** [@KZiemian](https://discourse.julialang.org/u/KZiemian)\
**Replies:** 22\
**Last updated:** [June 20, 2019, 3:48pm UTC](https://discourse.julialang.org/t/about-julia-and-lisp/25119 "2019-06-20T15:48:27Z")

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Being amateur Common Lisp user I often find part of Julia quite familiar. Definitely some very good Lisp programmers are here and I will be glad to hear some of them reflection on Lisp family and Julia.

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## [Retriving the Tableau from Gurobi](https://discourse.julialang.org/t/retriving-the-tableau-from-gurobi/25468)

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**Author:** [@rcallen24](https://discourse.julialang.org/u/rcallen24)\
**Replies:** 2\
**Last updated:** [June 20, 2019, 3:11pm UTC](https://discourse.julialang.org/t/retriving-the-tableau-from-gurobi/25468 "2019-06-20T15:11:33Z")

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I am trying to get the tableau from Gurobi and running into some problems. I went through the gurobi github and reference manual and was able to put this together but it is erroring out. # dummy model m = direct\_model(G…

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## [Realtime streaming of tick data](https://discourse.julialang.org/t/realtime-streaming-of-tick-data/5713)

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**Author:** [@hgeorgako](https://discourse.julialang.org/u/hgeorgako)\
**Replies:** 9\
**Last updated:** [June 20, 2019, 2:55pm UTC](https://discourse.julialang.org/t/realtime-streaming-of-tick-data/5713 "2019-06-20T14:55:34Z")

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I have a black box model (written in Julia) that requires realtime tick data as an input. The output of this model needs to be pub-subbed out to clients listening on a socket or topic. I have dozens to potentially hund…

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## [Solving highly stiff chemical kinetics IVP using DiffEqBiological](https://discourse.julialang.org/t/solving-highly-stiff-chemical-kinetics-ivp-using-diffeqbiological/25247)

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**Author:** [@bjodah](https://discourse.julialang.org/u/bjodah)\
**Replies:** 21\
**Last updated:** [June 20, 2019, 2:55pm UTC](https://discourse.julialang.org/t/solving-highly-stiff-chemical-kinetics-ivp-using-diffeqbiological/25247 "2019-06-20T14:55:15Z")

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Hi, I’ve been looking into using DifferentialEquations.jl to solve some IVPs (chemical kinetics problems more precisely, something I have extensive experience working with using the scientific python stack). I was deli…

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## [Julian way of MATLAB ismember function?](https://discourse.julialang.org/t/julian-way-of-matlab-ismember-function/3740)

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**Author:** [@leejm516](https://discourse.julialang.org/u/leejm516)\
**Replies:** 16\
**Last updated:** [June 20, 2019, 2:24pm UTC](https://discourse.julialang.org/t/julian-way-of-matlab-ismember-function/3740 "2019-06-20T14:24:12Z")

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Let two arrays a = \["1", "4", "7"\] and b = \["1","2","3,"4","5"\]. In MATLAB, \[Lia,Locb\] = ismember(a, b) will lead to Lia = \[1, 1, 0\] Locb = \[1, 4, 0\] Quickly looking over docs, I coudn’t find a Julian equivalent of…

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## [Juno / JuliaInterpreter versions](https://discourse.julialang.org/t/juno-juliainterpreter-versions/25478)

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**Author:** [@sylvaticus](https://discourse.julialang.org/u/sylvaticus)\
**Replies:** 5\
**Last updated:** [June 20, 2019, 12:16pm UTC](https://discourse.julialang.org/t/juno-juliainterpreter-versions/25478 "2019-06-20T12:16:34Z")

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Hello, I am a bit lost on which version of Juno support debugging and if this is dependent from JuliaInterpreter.jl or not. I have Juno v0.7.0 (\[e5e0dc1b\] Juno v0.7.0), I don’t have JuliaInterpreter.jl but it seems I ha…

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## [Slice Arrays of Arrays](https://discourse.julialang.org/t/slice-arrays-of-arrays/25390)

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**Author:** [@Mikel\_Antonana](https://discourse.julialang.org/u/Mikel_Antonana)\
**Replies:** 4\
**Last updated:** [June 20, 2019, 10:33am UTC](https://discourse.julialang.org/t/slice-arrays-of-arrays/25390 "2019-06-20T10:33:35Z")

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I have an array of arrays: a=Array\[\[1,2,3,4\],\[11,12,13,14\],\[21,22,23,24\]\] How can I get second and third element of each array? \[\[2,3\],\[12,13\],\[22,23\]\] I have tried it but it does not work: a\[:,2:3\]

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## [Error:MethodError: no method matching getindex(::typeof(LCSlength), ::Int64)](https://discourse.julialang.org/t/error-no-method-matching-getindex-typeof-lcslength-int64/25464)

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**Author:** [@diwas07](https://discourse.julialang.org/u/diwas07)\
**Replies:** 3\
**Last updated:** [June 20, 2019, 8:05am UTC](https://discourse.julialang.org/t/error-no-method-matching-getindex-typeof-lcslength-int64/25464 "2019-06-20T08:05:52Z")

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Hello, I am new to programming. I am learning Julia through online resources. I tried to implement a code in dynamic programming to find Longest common sub sequence. But I get some error, that I do not understand. All…

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## [\[ANN\] MerkleTrees.jl](https://discourse.julialang.org/t/ann-merkletrees-jl/25472)

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**Author:** [@roshii](https://discourse.julialang.org/u/roshii)\
**Replies:** 0\
**Last updated:** [June 20, 2019, 7:34am UTC](https://discourse.julialang.org/t/ann-merkletrees-jl/25472 "2019-06-20T07:34:32Z")

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Dear all, I am pleased to announce MerkleTrees package. It is now only handling double SHA256 function, please feel free to modify the code to add support for other hash algorithm !!

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## [Why is convert not called for parametric type?](https://discourse.julialang.org/t/why-is-convert-not-called-for-parametric-type/25376)

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**Author:** [@tk3369](https://discourse.julialang.org/u/tk3369)\
**Replies:** 5\
**Last updated:** [June 20, 2019, 6:29am UTC](https://discourse.julialang.org/t/why-is-convert-not-called-for-parametric-type/25376 "2019-06-20T06:29:07Z")

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For parametric type, does the constructor not call convert automatically? julia\> struct Foo3{T} a::T b::Float64 end julia\> Foo3(1,2) ERROR: MethodError: no method matching Foo3(::Int64, ::I…

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## [Predict impact locations of astroid 2006QV89](https://discourse.julialang.org/t/predict-impact-locations-of-astroid-2006qv89/25416)

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**Author:** [@chakravala](https://discourse.julialang.org/u/chakravala)\
**Replies:** 10\
**Last updated:** [June 20, 2019, 5:53am UTC](https://discourse.julialang.org/t/predict-impact-locations-of-astroid-2006qv89/25416 "2019-06-20T05:53:26Z")

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Could someone use Julia to predict what location on Earth would be affected if 2006QV89 impacts Earth? I imagine it would depend on the Earth’s daily rotation at the time. Please let me know if somebody can predict what…

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## [Estimate most probable value from data](https://discourse.julialang.org/t/estimate-most-probable-value-from-data/25451)

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**Author:** [@favba](https://discourse.julialang.org/u/favba)\
**Replies:** 7\
**Last updated:** [June 19, 2019, 9:33pm UTC](https://discourse.julialang.org/t/estimate-most-probable-value-from-data/25451 "2019-06-19T21:33:05Z")

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I have discrete data from a continuous field. The data probability distribution is not known, but it has only one peak value, what I guess is called “mode” of the pdf. The normalized histograms from the data look like s…

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