Tag: data mining

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Data Science Development

AI code-writing assistant that understands data content and generates code

Recently I’ve encountred a client that predicts “in 6 month AI will be able to do much coding instead of man”.

…in years you’ll be able to on the fly, ask the AI to purchase a server, or create a website with X website builder… and basically, I bet it will write code on the fly on your demand where it connects to these tool’s APIs to really make things happen. It could do this now for some easy stuff but it’s unreliable and will mess up.

Now we’ve ancountered a interesing public repo, called Sketch. It’s AI code-writing assistant for Pandas (Python) users.

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Data Science

Random Forest vs Gradient boosting

The objective of the task is to build a model so that we can, as optimally as this data allows, relate molecular information, to an actual biological response.

We have shared the data in the comma separated values (CSV) format. Each row in this data set represents a molecule. The first column contains experimental data describing an actual biological response; the molecule was seen to elicit this response (1), or not (0). The remaining columns represent molecular descriptors (D1 through D1776), these are calculated properties that can capture some of the characteristics of the molecule – for example size, shape, or elemental constitution. The descriptor matrix has been normalized.

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Data Science

Bagging and Random Forest

In this post we do several tasks performing the Bagging and the Random Forest Classificators.

We gradually develop classifier for the Bagging on randomized trees that in its final stage matches the Random Forest algorithm.

We’ll also build the RandomForestClassifier of sklearn.ensemble and learn of its quality depending on (1) number of trees, (2) max features used for each tree node, and (3) max tree depth.

Bagging is an ensemble algorithm that fits multiple models on different subsets of a training dataset, then combines the predictions from all models.

Random forest is an extension of bagging that also randomly selects subsets of features used in each data sample.

Bagging-and-Random-Forest-ENGDownload
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Data Science

Sklearn Decision trees

We show how to work with Decision trees at the Sklearn library.

Sklearn.tree;  Sklearn tree examples

sklearn.decision_trees-ENGDownload
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Data Science

Bike Sharing Demand Problem, part 2 – Sklearn SGD regression model, scaling, transformation chain and Random Forest nonlinear model

The Bike Sharing Demand problem requires using historical data on weather conditions and bicycle rental to predict the number of occupied bicycles (rentals) for a certain hour of a certain day.

In the original problem statement, there are 11 features available. The feature set contains both real, categorical, and binary data. For the demonstration, a training sample bike_sharing_demand.csv is used from the original data.

See the Bike Sharing Demand, part 1 of the task where we performed some initial problem analysis.

sklearn.case_part2-bike-sharing-ENGDownload
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Data Science

Bike Sharing Demand Problem, part 1 – Sklearn regression model, scaling, transformation chain

The problem is taken from kaggle.com. Based on historical data on bicycle rental and weather conditions, it is necessary to evaluate the demand for bicycle rental.

In the original problem statement, there are 11 features available. The feature set contains both real, categorical, and binary data. For the demonstration, a training sample bike_sharing_demand.csv is used from the original data.

See the Bike Sharing Demand, part 2 of the task where we performed advanced problem analysis.

sklearn.case_part1-bike-sharing-ENGDownload
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Data Science

Finding Classifier parameters on the grid, Sklearn.grid_search

Let’s answer the question: how do the parameters of the model affect its quality? And how can we select the optimal parameters for the task to be solved? We will look at the grid_search module in the sklearn library and learn how to select model parameters from the grid.

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Challenge Data Science

Finding maximum likelihood estimate for the Bernoulli distribution parameter

“Out of the 15 bank customers to whom the manager offered to connect autopayments, four agreed. Service activation is a binary feature that can be described by the Bernoulli distribution.”.

Let’s find the maximum likelihood estimate for the parameter p out of such a sample.

1) Likelihood function:

L(Xn, p) = ∏ p[Xi=1]*(1−p)[Xi=0] = p^4 * (1-p)^11

2) We find the maximum likelihood estimate for the parameter p.
We logarithm L(Xn, p) and get the following:

ln(p^4 * (1-p)^11) = 4*ln(p) + 11*ln(1-p)

3) Now we take its derivative and equate it to zero to find p.
[4ln(p) + 11ln(1-p)]` = 4 (ln(p))` + 11 (ln(1-p))` = 4/p + 11/(1-p) * (-1) = 0
Following: 4/p = 11/(1-p) => 4(1-p) = 11p => 15p = 4 => p = 4/15 =~ 0.26667.

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Challenge Data Science

Linear regression in example: overfitting and regularization

In the post we will set up a linear model to predict the number of bike rentals depending on the calendar characteristics of the day and weather conditions. We will choose the weights of the features so that to catch all the linear dependencies in the data and at the same time do not take into account extra features. This way the model will not overfit and will make fairly accurate predictions on new data.

We’ll also interpret the found linear dependencies. That means we check whether the discovered pattern corresponds to common sense. The main purpose of the task is to show and explain by example what causes overfitting and how to overcome it.

The code as an IPython notebook

Overfitting-Regularization-Example-Solution-1Download
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Data Science

Linear models, Sklearn.linear_model, Regression

In this post we’ll show how to build regression linear models using the sklearn.linear.model module.

See also the post on classification linear models using the sklearn.linear.model module.

The code as an IPython notebook

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