Skip to main content

bugs - Streaming`LazyList`Testing may have a leak



Bug introduced in 10.2 and fixed in 10.3


Version 10.2; Win64 Enterprise.


I'm seeing this message...



data::shdw: Symbol data appears in multiple contexts {Streaming`LazyList`Testing`, Global`}; definitions in context Streaming`LazyList`Testing` may shadow or be shadowed by other definitions.



... while executing some transformations on a big Dataset. I'm not convinced that I created the Global`data symbol explicitly; it's certainly the name of local symbols within Modules I have though.


I wonder though if there is a risk of a collision if I actually give data a value now.



Answer



UPDATE The behaviour no longer occurs in version 10.3.




Here are minimal reproduction steps, from a fresh 10.2.0 kernel:


Module[{data = {{1}}}, data // Dataset // Transpose]

(*
data::shdw: Symbol data appears in multiple contexts {Streaming`LazyList`Testing`,Global`};
            definitions in context Streaming`LazyList`Testing` may shadow or
            be shadowed by other definitions. >>
*)


After executing this, the $ContextPath looks suspicious:


$ContextPath

(* {"Streaming`LazyList`Testing`", "Streaming`", "StreamingLoader`",
    "IconizeLoader`", "CloudObjectLoader`", "PacletManager`",
    "System`", "Global`"} *)

Diagnosis


Upon further investigation, the problem appears to involve two causes. First, the streaming framework unconditionally loads and executes its test suite, adding it to the context path. To see this, inspect the following file:


NotebookOpen @ FileNameJoin @

  {"SystemFiles","Components","Streaming","StreamingLoader.m"}

... and note the following lines near the top:


Get[FileNameJoin[{DirectoryName[$InputFileName],"TestDSL.m"}]];
    Block[{$ContextPath},
        Get[FileNameJoin[{DirectoryName[$InputFileName],"Tests.m"}]]
]

The second cause appears to be related to a cyclic dependency between the Streaming` and Dataset` packages (and possible between other packages as well). Dataset`$AvailableBackends contains an implicit reference to Streaming`CachedObject, triggering a load via Package`ActivateLoad. The Streaming` package, in turn, has an explicit dependency upon the Dataset` package.


Normally, the act of auto-loading a package makes no changes to the $ContextPath. The presence of cyclic dependencies has historically interfered with the preservation of this path, so I suspect that it is at least part of the problem here.



Partial Workaround


The effects of both problems can be reduced by pre-loading the Streaming` package as the first action of a new kernel session:


Quiet @ Block[{$ContextPath}, Needs["Streaming`"]]

This preloading action leaves us with a cleaner environment:


Module[{data = {{1}}}, data // Dataset // Transpose]
(* Dataset[...] *)

$ContextPath
(* {"StreamingLoader`", "IconizeLoader`", "CloudObjectLoader`",

    "PacletManager`", "System`", "Global`"} *)

The observant reader will have noticed the presence of Quiet in the preloading step. It is needed to suppress another symbol conflict between System`ToCamelCase and GeneralUtilities`ToCamelCase. It would appear that there are similar auto-loading issues elsewhere. Therefore this solution can only really be considered as a partial work-around.


Comments

Post a Comment

Popular posts from this blog

plotting - Plot 4D data with color as 4th dimension

I have a list of 4D data (x position, y position, amplitude, wavelength). I want to plot x, y, and amplitude on a 3D plot and have the color of the points correspond to the wavelength. I have seen many examples using functions to define color but my wavelength cannot be expressed by an analytic function. Is there a simple way to do this? Answer Here a another possible way to visualize 4D data: data = Flatten[Table[{x, y, x^2 + y^2, Sin[x - y]}, {x, -Pi, Pi,Pi/10}, {y,-Pi,Pi, Pi/10}], 1]; You can use the function Point along with VertexColors . Now the points are places using the first three elements and the color is determined by the fourth. In this case I used Hue, but you can use whatever you prefer. Graphics3D[ Point[data[[All, 1 ;; 3]], VertexColors -> Hue /@ data[[All, 4]]], Axes -> True, BoxRatios -> {1, 1, 1/GoldenRatio}]
Post a Comment
Read more

plotting - Filling between two spheres in SphericalPlot3D

Manipulate[ SphericalPlot3D[{1, 2 - n}, {θ, 0, Pi}, {ϕ, 0, 1.5 Pi}, Mesh -> None, PlotPoints -> 15, PlotRange -> {-2.2, 2.2}], {n, 0, 1}] I cant' seem to be able to make a filling between two spheres. I've already tried the obvious Filling -> {1 -> {2}} but Mathematica doesn't seem to like that option. Is there any easy way around this or ... Answer There is no built-in filling in SphericalPlot3D . One option is to use ParametricPlot3D to draw the surfaces between the two shells: Manipulate[ Show[SphericalPlot3D[{1, 2 - n}, {θ, 0, Pi}, {ϕ, 0, 1.5 Pi}, PlotPoints -> 15, PlotRange -> {-2.2, 2.2}], ParametricPlot3D[{ r {Sin[t] Cos[1.5 Pi], Sin[t] Sin[1.5 Pi], Cos[t]}, r {Sin[t] Cos[0 Pi], Sin[t] Sin[0 Pi], Cos[t]}}, {r, 1, 2 - n}, {t, 0, Pi}, PlotStyle -> Yellow, Mesh -> {2, 15}]], {n, 0, 1}]
Post a Comment
Read more

plotting - Mathematica: 3D plot based on combined 2D graphs

I have several sigmoidal fits to 3 different datasets, with mean fit predictions plus the 95% confidence limits (not symmetrical around the mean) and the actual data. I would now like to show these different 2D plots projected in 3D as in but then using proper perspective. In the link here they give some solutions to combine the plots using isometric perspective, but I would like to use proper 3 point perspective. Any thoughts? Also any way to show the mean points per time point for each series plus or minus the standard error on the mean would be cool too, either using points+vertical bars, or using spheres plus tubes. Below are some test data and the fit function I am using. Note that I am working on a logit(proportion) scale and that the final vertical scale is Log10(percentage). (* some test data *) data = Table[Null, {i, 4}]; data[[1]] = {{1, -5.8}, {2, -5.4}, {3, -0.8}, {4, -0.2}, {5, 4.6}, {1, -6.4}, {2, -5.6}, {3, -0.7}, {4, 0.04}, {5, 1.0}, {1, -6.8}, {2, -4.7}, {3, -1....
Post a Comment
Read more