Collatz Conjecture

  Python Day 4: Collatz Conjecture Some of the students used to ask me, why do we have to learn calculus? I told them because if they are good at calculus then they may good at abstract algebra and number theory, and eventually can be the front page of the People’s Magazine like Andrew Wiles. (Andrew Wiles proved Fermat’s Last Theorem).

SAS Format

SAS Day 19: Format   Background:  In clinical datasets, we usually use some shortcode to keep the data to be concise, meanwhile, we want to generate detailed table labels from the datasets so the output is reader-friendly. For example, in the dataset, we have “F, M“, and we want to show “Female, Male” in output tables.


Derivatives 1:

Derivative is one of my favorite concepts; it is the fundamental idea of calculus. 

Derivative represents the rate of instantaneous change at the point a. 

Math started to make sense to me systematically from calculus.

One application is 

S(t): Distance

S'(t) = v(t) : velocity

S”(t)= v'(t)= a(t): accerlation

and dont forget S”'(t)= jerk 🙂 


Happy studying!

Song of the Wind

2019 Week 1:

SUZUKI BOOK 1: Song of the Wind


Practicing Note:

  • keep the first finger on the E string.
  •  piano (pp) on the second time.

I am still working on them. 

Happy Practicing! 🎻



 诗7                              清平调 1                             李白 云想衣裳花想容,春风拂槛露华浓 若非群玉山头见,会像瑶台月下逢。   这是诗仙李白写给小胖妞杨贵妃的诗, 真的是仙儿!我喜欢的杜牧写人间美女最多也是一句, 十里扬州春风路,卷上珠帘总不如。 这是平凡人的美的极致了吧。 李白写贵妃只有往天上写了,花是容貌就算了,云来织的衣裳,贵妃肯定是和仙女住在瑶池或者群玉山。 我总觉得李白诗里的杨贵妃,和提香画里的维纳斯很像。 都是胖胖的,仙气重,雍容华贵的。

The Game of 31

Thirty-One: Last weekend, 77 recommended me to watch a TV shows, High Intelligent Players, 高能玩家. Among the games they played, there is a game of 31, I think it is very interesting.

Fun Numbers

Python Day 3: Finding Fun Numbers All the maths fans know the story about 1729, the Ramanujan Number. One day Hardy visited Ramanujan in the hospital and said he took a taxi with a boring licence number, 1729. Ramanujan said:  it is a very interesting number; it is the smallest number expressible as the sum of two cubes in two different ways.

SAS Baseline

SAS Day 21: Baseline Value Background: How do we decide if the Weight Loss program/drug is effective or the laser operation improves the vision? Usually, we compare the weights before and after a program or track the vision before and after the eye laser surgery. The Change From Baseline is a critical measurement of efficacy analysis. Therefore, it is very crucial to record the…

SAS Miss function

SAS Day 20: Miss function There are two miss functions in SAS I really like, NMISS and CMISS. Problem: if we want to calculate the duration as aendt(Adverse Event End Date) – aestdt (Adverse Event Start Date). Ideally, we can use adurn=aendt-aestdt +1. However, in reality, we know there are high probabilities with missing AE dates.


SDTM day 6: Vital Sign Introduction: the Vital Sign domain captures all the measurements of body’s most basic functions, such as height, weight, blood pressure, heart rate… VS is a critical dataset in Drug Safety Analysis.

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