# Tag: programming | Page 0

Post #2
##### Optimization Learning Notes 1

book Public Date: 2020-06-20 08:42:04.801901

update Update Date: 2020-07-30 15:33:51.919974

Modeling
Mathematically, an optimization problem is usually represented as:
\begin{aligned} \text{maximize/minimize}_x &~ f(x) \ \text{subject to} &~ x \in \Omega \end{aligned}
where:
- $x$ is the decision variable
- $f$ is the objective function
- ...

Post #6
##### Optimization Learning Notes 2

book Public Date: 2020-06-20 17:12:00.571290

update Update Date: 2020-07-30 15:34:13.181702

Recall that the standard of an LP is like the following:
\begin{aligned} \min &~~~ c^Tx \ \text{subject to} &~~~ Ax = b \ &~~~ x \ge 0 \end{aligned}
where $x \in \mathbb R^n, b \in \mathbb R^m, A \in \mathbb R^{m\times n}$
In the following discussio...

Post #7
##### A Bad Day with MinGW TLS

book Public Date: 2020-06-23 18:59:52.751680

update Update Date: 2020-06-23 19:03:41.398479

It is always a bad experience to debug all day and get no progress at all.  Unfortunately, it is exactly want I was doing yesterday and I am really out of patience now.
It all started with a CI failure. Yes, as you can see from the following issues and com...

Post #8
##### Optimization Learning Notes 3

book Public Date: 2020-06-24 11:49:25.724151

update Update Date: 2020-07-30 15:34:37.990602

Two-Phase Method with Simplex Tableau
TL;DR, two-phase method involves two LP and can be solved by construct two simplex tableau.
However, there two things to consider:
- How to acquire the initial tableau in Phase I.
- How to make the transition from Ph...

Post #9
##### Happy Postgresql

book Public Date: 2020-06-25 03:27:40.366366

update Update Date: 2020-06-25 03:53:54.352076

I would like to summarize some highlights of postgresql usage in my own blog system.
Random Draw
It suddenly occurs to me that I would like to add a lucky draw function to my CMS. However, due to the data structure implementation, how to random select a ro...