Categories
Fun and trivia

Frk. Slimas Fornemmelse for Snot

Af Kostas Kefaloukos Danmark er et lille halvkoldt land, halvlangt mod nord. Det er ikke så koldt at der er særligt meget sne. Til gengæld blæser det meget og regner hele tiden. Disse vejrforhold gør at danskerne ofte bliver forkølede og udvikler store mængder af snot i næse og svælg. På samme måder som grønlænderne […]

Categories
AI Data

How to scrape images from the web

I’m interested in object detection and other computer vision tasks. For example, I’m working on a teddy-bear detector with my son. So, how do you quickly download images for a certain category? You can use this approach that I learned from a course on Udemy. In the above example, the crawler will find images in […]

Categories
Analytics Programming

How to fill missing dates in Pandas

Create a pandas dataframe with a date column: import pandas as pd import datetime   TODAY = datetime.date.today() ONE_WEEK = datetime.timedelta(days=7) ONE_DAY = datetime.timedelta(days=1)   df = pd.DataFrame({’dt’: [TODAY-ONE_WEEK, TODAY-3*ONE_DAY, TODAY], ‘x’: [42, 45,127]})import pandas as pd import datetime TODAY = datetime.date.today() ONE_WEEK = datetime.timedelta(days=7) ONE_DAY = datetime.timedelta(days=1) df = pd.DataFrame({‘dt’: [TODAY-ONE_WEEK, TODAY-3*ONE_DAY, TODAY], ‘x’: […]

Categories
Algorithms Analytics Machine Learning Programming

Cosine similarity in Python

Cosine similarity is the normalised dot product between two vectors. I guess it is called “cosine” similarity because the dot product is the product of Euclidean magnitudes of the two vectors and the cosine of the angle between them. If you want, read more about cosine similarity and dot products on Wikipedia. Here is how […]

Categories
Fun and trivia

Terms used in shipping

Now that I work in shipping, it is necessary to learn a bunch of new terms. Shipping is regulated under Admiralty Law and there are traditional documents and parties involved. Knowing what these are is crucial to understanding shipping. Legal documents There are three key documents involved with shipping: Bill of Lading (sometimes abbreviated as […]

Categories
AI

How to sample from softmax with temperature

Here is how to sample from a softmax probability vector at different temperatures. import numpy as np import matplotlib.pyplot as plt import matplotlib as mpl import seaborn as sns   mpl.rcParams[’figure.dpi’]= 144   trials = 1000 softmax = [0.1, 0.3, 0.6]   def sample(softmax, temperature): EPSILON = 10e-16 # to avoid taking the log of […]

Categories
Analytics

How to explore two-dimensional data with a heatmap

https://seaborn.pydata.org/generated/seaborn.heatmap.html

Categories
Analytics Programming Spatial stuff

How to display a Choropleth map in Jupyter Notebook

Here is the code: %matplotlib inline import geopandas as gpd import matplotlib as mpl # make rcParams available (optional) mpl.rcParams[’figure.dpi’]= 144 # increase dpi (optional)   world = gpd.read_file(gpd.datasets.get_path("naturalearth_lowres")) world = world[world.name != ‘Antarctica’] # remove Antarctica (optional) world[’gdp_per_person’] = world.gdp_md_est / world.pop_est g = world.plot(column=’gdp_per_person’, cmap=’OrRd’, scheme=’quantiles’) g.set_facecolor(’#A8C5DD’) # make the ocean blue (optional)%matplotlib […]

Categories
Algorithms Analytics Optimization Programming

(Integer) Linear Programming in Python

Step one: brew install glpk pip install pulpbrew install glpk pip install pulp Step two: from pulp import *   prob = LpProblem("test1", LpMinimize)   # Variables x = LpVariable("x", 0, 4, cat="Integer") y = LpVariable("y", -1, 1, cat="Integer") z = LpVariable("z", 0, cat="Integer")   # Objective prob += x + 4*y + 9*z   […]

Categories
Geography

Things that are visible from space, the Garzweiler Surface Mine

I was looking at arial photos of north-western Europe in Google Maps when I noticed a big white dot on the map! I thought, what the hell? To satisfy my curiosity I decided to zoom in for further investigation. It turns out that the big white dot is a giant surface mine. The 48 km² […]