Tag: machine learning

Laptop for data science and machine learning

We recommend and review some laptops/notebooks suitable for data science and machine learning.

Firstly, we state the 4 core important specs (specifications) for laptops for data science and machine learning.

1) RAM: Should be 8GB or higher.

2) CPU: Should be Intel Core i5, or even better Intel Core i7.

3) Storage: Should be at least 256 GB SSD.

4) GPU: Optional, but good to have for deep learning. (Note that Mac GPUs are not usable for deep learning.)

RAM and CPU are necessary in order to conduct computations successfully and within a reasonable time. Storage is necessary to process big data which can potentially be several gigabytes. GPU is useful to speed up deep learning, but is optional since there are many cloud or server options available.

For concrete recommendations, we recommend the following 5 laptops. Certainly, there could be other laptops that are equally suitable for data science and machine learning, do comment below if you have a good suggestion!

1)

ASUS ROG Strix Scar 17 Gaming Laptop, 17.3” 300Hz FHD IPS Type, NVIDIA GeForce RTX 2070 Super, Intel Core i7-10875H, 16GB DDR4, 1TB PCIe SSD, Per-Key RGB Keyboard, Wi-Fi 6, Windows 10, G732LWS-DS76

2)

Dell XPS 15 7590 Laptop 15.6 inch, 4K UHD OLED InfinityEdge, 9th Gen Intel Core i7-9750H, NVIDIA GeForce GTX 1650 4GB GDDR5, 256GB SSD, 16GB RAM, Windows 10 Home, XPS7590-7572SLV-PUS, 15-15.99 inches

3)
New Apple MacBook Pro (16-inch, 16GB RAM, 512GB Storage, 2.6GHz Intel Core i7) – Space Gray

4)

2020 Lenovo ThinkPad T590 15.6″ FHD Full HD (1920×1080) Business Laptop (Intel Quad-Core i7-8565U, 16GB RAM, 512GB SSD) Backlit, Type-C Thunderbolt 3, RJ-45, Webcam, Windows 10 Pro IST Computers

5)
HP Pavilion 15-inch Laptop, Intel Core i7, 16 GB RAM, 512 GB SSD Storage, Intel Iris Plus Graphics, Windows 10 Pro, Amazon Alexa Voice Compatible (15-cs3019nr, Mineral Silver)

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Updating Spyder takes forever

Spyder is a Python IDE that is bundled together with the Anaconda distribution.

There are some problems that are commonly faced when it comes to updating Spyder. One way to update Spyder is to open Anaconda Navigator and click the settings button which has an option to update Spyder. But the problem is that the process can take a very long time. The process shows that it is “loading packages of /User/…/opt/anaconda3”.

Updating Spyder is constricted by …

Another way to update Spyder is to type “conda update spyder” in the terminal. A problem that can crop up is the error message: “updating spyder is constricted by …”

Anaconda stuck updating Spyder [Solved]

For my case, it turns out that the version of Anaconda Navigator is outdated. Hence, I first updated Anaconda Navigator to the latest version.

Then, instead of clicking “Update application” which still didn’t quite work, we click on “Install specific version” and choose the latest version of Spyder (Spyder 4.1.5 in this case).

Then, the updating of Spyder in Anaconda Navigator worked perfectly!

How to update Spyder using Anaconda-Navigator: Click “Install specific version” instead of “Update application”.

Best Udemy Data Science / Machine Learning / AI Courses

During this current lockdown period it is a good idea to pick up a data science skill. Most occupations can benefit from such a skill, including engineers, accountants, teachers, even students. Who knows, one day you may find deep learning useful!

In this page we introduce various Udemy courses (which come with certificates that you can put on your LinkedIn profile) that are the best in their class, be it for data science, machine learning (including deep learning), and AI (Artificial Intelligence).

Best Udemy Python Course

Currently, Python is the most popular language for data science and machine learning.  R is the second most popular language, and is especially good for statistics.

Hence, this Machine Learning A-Z™: Hands-On Python & R In Data Science Course is perfect as it introduces two of the most popular programming languages in one course! You will learn Machine Learning (ML) in the process as well, which is a great bonus.

If you only want to focus on Python, then check out 2020 Complete Python Bootcamp: From Zero to Hero in Python. It is designed to bring you from zero knowledge to a respectable expert in Python if you complete the course and exercises.

Best Udemy courses for data science

In the Python for Data Science and Machine Learning Bootcamp  course, students can learn how to use NumPy, Pandas, Seaborn, Matplotlib, Plotly, Scikit-Learn, Machine Learning, Tensorflow, and more! The aforementioned packages are all classic and popular in data science, data analysis and data visualization.

The Data Science Course 2020: Complete Data Science Bootcamp is another bootcamp style course that gives you complete Data Science training in: Mathematics, Statistics, Python, Advanced Statistics in Python, Machine & Deep Learning. It is especially suitable for beginners, as well as intermediate students who need to brush up on their skills.

Best Udemy course for Deep Learning

Deep learning (DL) is a subbranch of machine learning that is recently very hot and popular due to its superior accuracy in tasks such as image classification and NLP (natural language processing).

The Deep Learning A-Z™: Hands-On Artificial Neural Networks allows students to learn how to create Deep Learning Algorithms in Python from two Machine Learning & Data Science experts. Templates included, which is very important. Essentially, you can use and modify the templates to suit your individual task at hand.

Complete Guide to TensorFlow for Deep Learning with Python is a course for learn how to use Google’s Deep Learning Framework – TensorFlow with Python! Solve problems with cutting edge techniques! TensorFlow is one of the more popular deep learning framework, and is slightly ahead in popularity compared to its closest rival, PyTorch.

Udemy course benefits

The first benefit of Udemy courses, is that you get to learn content from the top trainers. Often, these courses are superior to free YouTube content, and may be even better than the courses in your school.

The second benefit is that Udemy provides a certificate upon completion that you can list in your CV, as well as put in your LinkedIn profile. This is especially important if you are trying to transition into a data scientist job from another field, like engineering or physical sciences.

What is your favorite Udemy course for AI/ML/DL? Feel free to comment below!

Best Pattern Recognition and Machine Learning Book (Bishop)


Pattern Recognition and Machine Learning (Information Science and Statistics)

The above book by Christopher M. Bishop is widely regarded as one of the most comprehensive books on Machine Learning. At over 700 pages, it has coverage of most machine learning and pattern recognition topics.

It is considered very rigorous for a machine learning (data science) book, but yet has a lighter touch than a pure mathematics or theoretical computer science book. Hence, it is perfect as a reference book or even textbook for students self learning the subject from the ground up (i.e. students who want to understand instead of just blindly apply algorithms).

A brief overview of the contents covered (taken from the contents page of the book):

  1. Introduction

  2. Probability Distributions

  3. Linear Models for Regression

  4. Linear Models for Classification

  5. Neural Networks

  6. Kernel Methods

  7. Sparse Kernel Machines

  8. Graphical Models

  9. Mixture Models and EM

  10. Approximate Inference

  11. Sampling Methods

  12. Continuous Latent Variables

  13. Sequential Data

  14. Combining Models

Python save csv to folder

In Python (pandas), saving a .csv file to a particular folder is not that hard, but then it may be confusing to beginners.

The packages we need to import are:

import pandas as pd
import os.path

Say, your folder name is called “myfolder”, and the dataframe you have is called “df”. To save it insider “myfolder” as “yourfilename.csv”, the following code does the job:

df.to_csv(os.path.join('myfolder','yourfilename.csv'))

The reason this may be difficult for beginners is that beginners may not know of the existence of the os.path.join method, which is the recommended method for joining one or more path components.

Recall & Precision vs Sensitivity & Specificity

Other than accuracy rate, there are various metrics for machine learning to measure how “accurate” the model is.

Some popular ones for binary classification are sensitivity (true positive rate) and specificity (true negative rate).

In computer science, recall and precision are also common metrics.

It can be quite confusing to remember offhand what each metric means, and how they are related.

To summarize, the following are equivalent (for binary classification):

sensitivity = recall of positive class

specificity = recall of negative class

Sample source: https://onlinelibrary.wiley.com/doi/pdf/10.1002/cmdc.201700180

Other than the above metrics mentioned, there are also many other metrics, such as F1 score, etc.

pip install keeps installing old/outdated packages

This article is suitable for solving the following few problems:

  1. module ‘sklearn.tree’ has no attribute ‘plot_tree’
  2. pip install (on Spyder, Anaconda Prompt, etc.) does not install the latest package.

The leading reason for “module ‘sklearn.tree’ has no attribute ‘plot_tree” is because the sklearn package is outdated.

Sometimes “pip install scikit-learn” simply does not update the sklearn package to the latest version. Type “print(sklearn.__version__)” to get the version of sklearn on your machine, it should be at least 0.21.

The solution is to force pip to install the latest package:

pip install --no-cache-dir --upgrade <package>

In this case, we would replace <package>  by “scikit-learn”.

Sometimes, pip install does not work in the Spyder IPython console, it displays an error to the effect that you should install “outside the IPython console”. This is not normal (i.e. it should not happen), but as a quick fix you can try “pip install” in Anaconda Prompt instead. It is likely that something wrong went on during the installation of Anaconda, Python, and the long-term solution is to reinstall Anaconda.

caret package in R: known issue when converting factor variables

In the R language, often you have to convert variables to “factor” or “categorical”. There is a known issue in the ‘caret’ library that may cause errors when you do that in a certain way.

The correct way to convert variables to ‘factor’ is:

trainset$Churn = as.factor(trainset$Churn)

In particular, “the train() function in caret does not handle factor variables well” when you convert to factors using other methods.
(See https://rpubs.com/SulmanKhan/444033)

Basically, if you use other ways to convert to ‘factor’, the code may still run, but there may be some ‘weird’ issues that leads to inaccurate predictions (for instance if you are doing logistic regression, decision trees, etc.)

How to save sklearn tree plot as file (Vector Graphics)

The Scikit-Learn (sklearn) Python package has a nice function sklearn.tree.plot_tree to plot (decision) trees. The documentation is found here.

However, the default plot just by using the command

tree.plot_tree(clf)

could be low resolution if you try to save it from a IDE like Spyder.

The solution is to first import matplotlib.pyplot:

import matplotlib.pyplot as plt

Then, the following code will allow you to save the sklearn tree as .eps (or you could change the format accordingly):

plt.figure()
tree.plot_tree(clf,filled=True)  
plt.savefig('tree.eps',format='eps',bbox_inches = "tight")

To elaborate, clf is your Decision Tree classifier (to be defined before plotting the tree):

# Example from https://scikit-learn.org/stable/modules/generated/sklearn.tree.plot_tree.html
clf = tree.DecisionTreeClassifier(random_state=0)
clf = clf.fit(iris.data, iris.target)

The outcome is a Vector Graphics format (.eps) tree that will retain its full resolution when zoomed in. The bbox_inches=”tight” command prevents truncating of the image. Without that command, sometimes the sklearn tree will just be cropped off and be incomplete.

Introduction to Machine Learning

Very good introduction to Machine Learning by Google. Google is the developer of Tensorflow (on which the Keras package is built). The other platform for Machine Learning is Pytorch by Facebook.

So far, the best introductory book to Machine Learning seems to be the one by the founder of Keras, called “Deep Learning with Python”. See also Best Machine Learning / Deep Learning Books.