Math

Mental Math: Calculate ... in Your Head

Apr 4, 2021

Recently I start realising the decline of my math instinct. The other day, it took me a few minutes to remember the Gaussian sum and more minutes for the very basic Trigonometry. The only thing about calculation remains sharp in my mind is probably the Chinese multiplication table. I’m having a hard time to admit that it would be hard for me to pass a high school entrance math tests.

CBF1-04: Where I live

Apr 4, 2019

—Bonjour tout le monde! —Salut, je m’appelle Anna. —Et moi, je m’appelle Mark. Je suis votre professeur. On va commencer. —Est-ce que tu es prète? —Je suis prète pour apprendre le français avec Coffee Break French. (I’m ready to learn French with Coffee Break French.) Je suis (I am) Je suis écossais,e. (I am Scottish.) Nationality: anglais,e (English) américain,e (American) canadien,ne (Canadian) —D’où viens-tu? (Where do you come from?) —Je suis écossais, je viens de Glasgow.

CBF1-03: Where I come from

Apr 4, 2019

Bonjour, tout le monde! Alors, on va commencer. – Est-ce que tu es prète? – Oui, je suis prète. FR PRON EN CL professeur /pʀɔfesœʀ/ teacher M n. votre (vos) /votʀ/ yours je suis votre professeur I am your teacher alors /alɔʀ/ so, then adv. on /ɔ̃/ one, we, they, pron. va /va/ go, be, come, aller v.

CBF1-02: Greetings

Apr 4, 2019

Nous voici, est-ce que tu es prêt? FR PRON EN CL exactement /ɛɡzaktəmɑ̃/ exactly avec vous /avɛk vu/ with you bonjour /bɔ̃ʒuʀ/ good morning bon /bɔn/ good M adj. jour /ʒuʀ/ day bonsoir /bɔ̃swaʀ/ good evening soir /swaʀ/ evening M n. bonne nuit /bɔne nɥi/ good night bonne /bɔne/ good F adj.

CBF1-01: How are you?

Apr 4, 2019

Est-ce que tu es prêt? Oui,je suis prète. FR PRON EN oui /wi:/ yes non /nɔ̃/ no ça va? /sa va/ how are you? ça va things are fine bien /bjɛ̃/ well ça va bien things are going well merci /mɛʀsi/ thank you ça va bien, merci I’m fine, thanks et toi?

The ultimate tour to my python environment

Nov 11, 2017

Like someone else who stepped into coding from other random fields might have experienced, I do find the lack of system level knowledge could significantly hinder the workflow. In a word, how to get a smoothly working environment for all your tools with minimum conflicts and collapse? Recently I encountered some After spending a whole day, Here I mainly talk about Python,

Computing a Fibonacci sequence

Oct 10, 2017

I came across a question in codewars which is based on the calculation of the *n*th number in the Fabonacci sequence. Remember back in high school we were asked to derive this via MI, which is a long story. And thanks to the power of computation that gives options to simplify this process. Anyway, here are a few ways for solution: 1. Math function This is put at the first place because for people who do math it is the most intuitive action to just calculate the result from $$F_n = \frac{1}{sqrt(5)}\bigg[ \big(\frac{1+sqrt(5)}{2}\big)^n - \big(\frac{1-sqrt(5)}{2}\big)^n \bigg]$$ However, the calculation

Quick ML: logistic regression

Oct 10, 2017

Cost function $$J(\theta) = \frac{1}{2m} \sum^m_{i=1} (H_\theta(X^{(i)}) - y^{(i)})^2$$ $$Cost(h_\theta(X), y) = \begin{cases} -log(h_\theta(X)),&\text{if }y=1 \\ -log(1-h_\theta(X)),&\text{if }y=0 \end{cases} $$ P.S. Katex tips: in Hugo’s math mode, to get line separator for multi-line equations, use ‘\’ $\times 6$ instead of ‘\\‘. And if a function faild, add ‘\’ as escape char for random ‘_’s might help (annoying…I know…)

Quick ML: linear regression

Oct 10, 2017

Here is a series of course notes migration, in order to say-goodbye to the text books and my messy physical notepads. Hypothesis model $$H_\theta(X) = \theta^T X = \theta_0\cdot 1 + \theta_1\cdot x_1 + \cdots + \theta_n\cdot x_n$$ $\theta\in n+1$ column vector, $X\in (n+1)\times m$ matrix when having $m$ training cases. Cost function $$J(\theta) = \frac{1}{2m} \sum^m_{i=1} (H_\theta(X^{(i)}) - y^{(i)})^2$$

Getting there... static site

Sep 9, 2017

I have been thinking for a while putting up a blog recording random stuff. It might be a better way to keep track what I’ve been looking at and regularize some massy notes. After wasting a summer leaving the plain template lying in my disk folder, it’s good to start now since the season is getting closer to my background picture. With the free domain provided by Github, there has been a good amount of choices for set up a static website/blog.

Mental Math: Calculate ... in Your Head

Computing a Fibonacci sequence

lxip

Mental Math: Calculate ... in Your Head

CBF1-04: Where I live

CBF1-03: Where I come from

CBF1-02: Greetings

CBF1-01: How are you?

The ultimate tour to my python environment

Computing a Fibonacci sequence

Quick ML: logistic regression

Quick ML: linear regression

Getting there... static site