November 2018
Intermediate to advanced
272 pages
6h 51m
Japanese
book
エレガントなSciPy ―Pythonによる科学技術計算
by Juan Nunez-Iglesias, Stéfan van der Walt, Harriet Dashnow, 山崎 邦子, 山崎 康宏
Content preview from エレガントなSciPy ―Pythonによる科学技術計算
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124
5 章 疎行列を用いた分割表
5.3
疎行列の適用例：画像変換
scikit-image
ライブラリや
SciPy
ライブラリには、効率的な画像変換（回転やワープ）のための
アルゴリズムが用意されていますが、もしあなたが
NumPy
国宇宙局長官で、新たに打ち上げられ
た木星（
Jupyter
）軌道の宇宙探査機からストリーミングされてくる何百万という数の画像を回転
させる必要があるとしたら、どうすればよいでしょうか。
このような場合には、コンピュータの性能を余すところなく利用したいでしょう。実は、これか
ら紹介する、疎演算子を用いた方法は、同じ変換を繰り返し適用する場合には、
SciPy
の
ndimage
の最適化された
C
のコードすら凌駕するのです。
scikit-image
の以下のカメラマンのテスト画像を、データの例として使います。
# Make plots appear inline, set custom plotting style
%matplotlib inline
プロットをインライン表示させ、自前のプロットスタイルを設定する。
import matplotlib.pyplot as plt
plt.style.use('style/elegant.mplstyle')
フルネーム 注釈 利用例 欠点
bsr_matrix
Block Sparse Row CSR
に類似 ･
密な部分行列の格納
･
有限要素法や微分方程式な
どの離散化問題の数値解析
によく使われる
coo_matrix
Coordinate
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O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.