おおちゃく...

Sparkのドキュメントによると、DataFrameは、データの分散コレクションを「名前付きの列」に整理したもので、概念的には、リレーショナルデータベースのテーブルや、R、Pythonのデータフレームと同等だが、グラフデータ用に「高度に最適化されている」という。 　GraphFrameは構造化データファイル、Apache Hiveのテーブル、外部データベース、既存のリレーショナルデータベースなど、多様なソースから構築できる。Scala、Java、Python、R向けのAPIが用意されている。 　Databricksによると、GraphFramesはDataFrameが持つスケーラビリティと高いパフォーマンスの恩恵を受けており、Scalaの他、Java、Pythonでグラフデータ処理を利用するための単一のAPIを提供する。これにより、PythonとJavaから「GraphX」の全てのアルゴリズムを利用可能になった。この他、SparkのGraphXライブラリと似た一般的なグラフデータ処理をサポートする他、「幅優先探索（BFS）」や「モチーフ探索」といった新しいアルゴリズムにも対応する。 　また、GraphFramesはDataFrameのデータソースを完全にサポートするので、Hadoop向けの列指向ストレージ「Parquet」形式や、JSON、CSVなど、さまざまなデータフォーマットを利用できる。 　同社は公式ブログで、ソーシャルネットワークを簡単なグラフとして表現した例を用いてGraphFramesを紹介している（ユーザーが「点」、ユーザー間の関係が「辺」）。「どのユーザーが最も影響力があるか」「ユーザーAとBは知らない者同士だが、引き合わせるべきか」といった問いに対して、グラフのクエリやアルゴリズムを使って答えを出すことができるという。 　この例では、ユーザー（点）は「名前」「年齢」を、ユーザー間の関係（辺）は「関係タイプ」といった属性を持つが、GraphFramesでは点と辺をDataFrameとして保存する。多くのクエリはDataFrame（またはSQL）クエリとなるため「グラフに対するクエリを簡単に表現できる」と、Databricksは説明している。 Apache Hive 2.0では「Hive-on-Spark parallel ORDER BY」が実装 　Spark周辺のプロダクト開発が活性化しており、直近では、米クラウデラが開発を主導するHadoop向けSQLクエリエンジンの最新版「Apache Hive 2.0」でも、Sparkに対する並列ソート機能「Hive-on-Spark parallel ORDER BY」などが新たに実装されている。

http://headlines.yahoo.co.jp/hl?a=20160307-00000092-zdn_ait-sci

カシオペアin尾久車両センター

きょう行ってきた。ダ・ヴィンチ展。4月10日までなので行ってない人は是非。前の桜もちょうど見頃。#ダ・ヴィンチ展

Solar System: 10 Things to Know This Week

January 8: Images for Your Computer or Phone Wallpaper

Need some fresh perspective? Here are 10 vision-stretching images for your computer desktop or phone wallpaper. These are all real pictures, sent recently by our planetary missions throughout the solar system. You’ll find more of our images at solarsystem.nasa.gov/galleries, images.nasa.gov and www.jpl.nasa.gov/spaceimages.

Applying Wallpaper: 1. Click on the screen resolution you would like to use. 2. Right-click on the image (control-click on a Mac) and select the option ‘Set the Background’ or 'Set as Wallpaper’ (or similar).

1. The Fault in Our Mars

This image from our Mars Reconnaissance Orbiter (MRO) of northern Meridiani Planum shows faults that have disrupted layered deposits. Some of the faults produced a clean break along the layers, displacing and offsetting individual beds.

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2. Jupiter Blues

Our Juno spacecraft captured this image when the spacecraft was only 11,747 miles (18,906 kilometers) from the tops of Jupiter’s clouds – that’s roughly as far as the distance between New York City and Perth, Australia. The color-enhanced image, which captures a cloud system in Jupiter’s northern hemisphere, was taken on Oct. 24, 2017, when Juno was at a latitude of 57.57 degrees (nearly three-fifths of the way from Jupiter’s equator to its north pole) and performing its ninth close flyby of the gas giant planet.

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3. A Farewell to Saturn

After more than 13 years at Saturn, and with its fate sealed, our Cassini spacecraft bid farewell to the Saturnian system by firing the shutters of its wide-angle camera and capturing this last, full mosaic of Saturn and its rings two days before the spacecraft’s dramatic plunge into the planet’s atmosphere on Sept. 15, 2017.

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4. All Aglow

Saturn’s moon Enceladus drifts before the rings, which glow brightly in the sunlight. Beneath its icy exterior shell, Enceladus hides a global ocean of liquid water. Just visible at the moon’s south pole (at bottom here) is the plume of water ice particles and other material that constantly spews from that ocean via fractures in the ice. The bright speck to the right of Enceladus is a distant star. This image was taken in visible light with the Cassini spacecraft narrow-angle camera on Nov. 6, 2011.

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5. Rare Encircling Filament

Our Solar Dynamics Observatory came across an oddity this week that the spacecraft has rarely observed before: a dark filament encircling an active region (Oct. 29-31, 2017). Solar filaments are clouds of charged particles that float above the Sun, tethered to it by magnetic forces. They are usually elongated and uneven strands. Only a handful of times before have we seen one shaped like a circle. (The black area to the left of the brighter active region is a coronal hole, a magnetically open region of the Sun).

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6. Jupiter’s Stunning Southern Hemisphere

See Jupiter’s southern hemisphere in beautiful detail in this image taken by our Juno spacecraft. The color-enhanced view captures one of the white ovals in the “String of Pearls,” one of eight massive rotating storms at 40 degrees south latitude on the gas giant planet. The image was taken on Oct. 24, 2017, as Juno performed its ninth close flyby of Jupiter. At the time the image was taken, the spacecraft was 20,577 miles (33,115 kilometers) from the tops of the clouds of the planet.

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7. Saturn’s Rings: View from Beneath

Our Cassini spacecraft obtained this panoramic view of Saturn’s rings on Sept. 9, 2017, just minutes after it passed through the ring plane. The view looks upward at the southern face of the rings from a vantage point above Saturn’s southern hemisphere.

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8. From Hot to Hottest

This sequence of images from our Solar Dynamics Observatory shows the Sun from its surface to its upper atmosphere all taken at about the same time (Oct. 27, 2017). The first shows the surface of the sun in filtered white light; the other seven images were taken in different wavelengths of extreme ultraviolet light. Note that each wavelength reveals somewhat different features. They are shown in order of temperature, from the first one at about 11,000 degrees Fahrenheit (6,000 degrees Celsius) on the surface, out to about 10 million degrees in the upper atmosphere. Yes, the sun’s outer atmosphere is much, much hotter than the surface. Scientists are getting closer to solving the processes that generate this phenomenon.

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9. High Resolution View of Ceres

This orthographic projection shows dwarf planet Ceres as seen by our Dawn spacecraft. The projection is centered on Occator Crater, home to the brightest area on Ceres. Occator is centered at 20 degrees north latitude, 239 degrees east longitude.

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10. In the Chasm

This image from our Mars Reconnaissance Orbiter shows a small portion of the floor of Coprates Chasma, a large trough within the Valles Marineris system of canyons. Although the exact sequence of events that formed Coprates Chasma is unknown, the ripples, mesas, and craters visible throughout the terrain point to a complex history involving multiple mechanisms of erosion and deposition. The main trough of Coprates Chasma ranges from 37 miles (60 kilometers) to 62 miles (100 kilometers) in width.

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Explore and learn more about our solar system at: solarsystem.nasa.gov/. 

Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com.

久々の投稿

久々の投稿である．

Twitter の騒動の後，Tumblr が ActivityPub に対応すると知って，云年ぶりに戻ってきた感じである．

ところで，Tumblr の markdown って，プログラムを表示するときにどう表示されるのか分からないので，試す．

def func(a, b): return a+b

Hello.

I still is making Tumblr's home page. this work is very hard.but I can belieave I perfect this work.

約10億ドルもの巨費を投じて買収したTumblrの資産価値が買収してからたったの3年でゼロにまでなるという事態が実際に生じた場合、買収を主導したYahoo CEOのMarissa Mayer（マリッサ・マイヤー）の経営責任問題も浮上することとなる。

http://www.businessnewsline.com/news/201603010942110000.html