# Bobbie's Blog

## 不要计算

### -关于计算（Computation）的思考

A computation is a temptation that should be resisted as long as possible.
- John P. Boyd (Michigan)

Never do a calculation until you already know the answer.
- John Wheeler

Six months in the lab can save you a day in the library.
- Albert Migliori

Six months in the lab will save you: Half a day in the library or 30 minutes searching online.
- Paul G. Kotula

There are three great branches of science: theory, experiment, and computation.

Science is what we understand well enough to explain to a computer. Art is everything else we do.

Ninety-ninety rule: The first 90% of the code takes 90% of the time. The remaining 10% takes the other 90% of the time.

### 理解 — 计算

• 计算是用来验证你是不是理解一个概念或者方法的。如果你已经理解，计算的成功验证可以给你更多的信心；如果计算没有验证成功，你也找不出 bug 在哪里，那只说明一件事，你还没有完全理解。所以理解是计算的前提
• 计算是运用理解力去实践创造的过程。理解一个理论之后，你就可以通过计算让理论在现实中派上用场。比如理解了建筑学和材料科学，就可以用模拟地震来研究建筑结构的薄弱部分；但是模拟出残垣断壁，并不能反过来让你自动学会材料科学。又比如理解了椭圆积分，就可以运用 AGM 算法来轻易算出 $\pi$ 到数亿位的精度；但是通过读 AGM 算法那几行简单的代码，并不能反过来告诉你它为什么这么有效，也不能教会你椭圆积分。理解是计算的前提

Never do a calculation until you already know the answer.

Things may seem magical, but to the people who understand math there is no magic. - Bobbie