Author Archives: Tech Admin

How to Resolve The Error “Illegal instruction (core dumped)” when Running “import tensorflow” in a Python Program

There are several ways to install TensorFlow on Ubuntu. The easiest way is to install via pip. Unfortunately, this easy installation may result in a bumpy first time experience of running TensorFlow. Consider the following one line Python script:

$ python -c 'import tensorflow as tf;'

This should be where the excitement begins, the moment where conviction about the new era of AI-powered banalities starts to bloom. Yet, the reality can be unexpectedly different. Executing the command may immediately raise this very infamous error:

Illegal instruction (core dumped)

This means that TensorFlow has crashed even before it does anything. What a surprise!

The good thing is that we can run gdb to debug Python and start analyzing the call stack. But what’s even better is that we can save the brilliance for later. This error has been repeatedly reported and has conveniently sit on its fame for a while, as reflected on the issue page. Continue reading

How to Build and Install The Latest TensorFlow without CUDA GPU and with Optimized CPU Performance on Ubuntu

In this post, we are about to accomplish something less common: building and installing TensorFlow with CPU support-only on Ubuntu server / desktop / laptop. We are targeting machines with older CPU, as for example those without Advanced Vector Extensions (AVX) support. This kind of setup can be a choice when we are not using TensorFlow to build a new AI model but instead only for obtaining the prediction (inference) served by a trained AI model. Compared with model training, the model inference is less computational intensive. Hence, instead of performing the computation using GPU acceleration, the task can be simply handled by CPU.

tl;dr The WHL file from TensorFlow CPU build is available for download from this Github repository.

Since we will build TensorFlow with CPU support only, the physical server will not need to be equipped with additional graphics card(s) to be mounted on the PCI slot(s). This is different with the case when we build TensorFlow with GPU support. For such case, we need to have at least one external (non built-in) graphics card that supports CUDA. Naturally, running TensorFlow with CPU pertains to be an economical approach to deep learning. Then how about the performance? Some benchmark results have shown that GPU performs better than CPU when performing deep learning tasks, especially for model training. However, this does not mean that TensorFlow CPU cannot be a feasible option. With proper CPU optimization, TensorFlow can exhibit improved performance that is comparable to its GPU counterpart. When cost is a more serious issue, let’s say we can only do the model training and inference in the cloud, leaning towards TensorFlow CPU can be a decision that also makes more sense from financial standpoint. Continue reading

Installing CUDA Toolkit 9.2 on Ubuntu 16.04: Fresh Install, Install by Removing Older Version, Install and Retain Old Version

In the previous post, we’ve proceeded with CUDA 9.1 installation on Ubuntu 16.04 LTS. As with other software that evolves, NVIDIA released CUDA 9.2 back in May. It is also safe to assume that CUDA 9.2 will not be final version. Newer version will may come soon or later and here we are left with the bogging question: “How can we upgrade safely without clobbering the currently working system?” Moreover, we may also wonder if there is a mechanism to rollback the change and live with current setup while recognizing that it’s not yet the time to upgrade.

This post will cover three scenarios of CUDA 9.2 installation: 1) fresh installation, 2) install to upgrade by removing old version, 3) install to upgrade and keep multiple versions. Continue reading

Command Cheatsheet: Checking Versions of Installed Software / Libraries / Tools for Deep Learning on Ubuntu 16.04

In the previous posts, we’ve walked through the installations and configurations for various components and libraries required for doing deep learning / artificial intelligence on a Ubuntu 16.04 box. The next step is to be productive, crunching codes and solving problems by applying various algorithms. At this stage, visits to StackOverflow, Github or other similar sites become more frequent. And here is when the problem may arise. Not all codes or snippets copied and pasted from such online references can immediately work. One of the reasons is that the code was indeed written for same software, library, or tool but at different version.

Interestingly, software components for machine learning present different way to obtain the versions. These variations can sometimes result in additional time spent to query “ubuntu get xyz version” on the search engine. This is okay for one component, but when the system becomes complex enough (for example machine learning meets big data for ETL), this can turn into a productivity killer due to unjustifiable time taken for navigating the search engine.

Why not build a list for that?

This post summarizes the shell commands used for obtaining the versions of machine learning-related software and libraries. Commands are embodied in categories that reflect the logical / functional unit the software component belongs to. Continue reading

ReactJS: Changing Default Port 3000 in create-react-app

If you are doing frontend development nowadays, you may have heard about ReactJS or may be actively using it in your projects. Introduced to the public five years ago, React has transformed into a library of choice for a lot of frontend developers that is easily certified by the enormous stars at its Github page (more than 100,000 stars). React was relicensed into MIT license almost a year ago, which only catapulted its popularity into a new high. The MIT license is a more commercial friendly license compared to the BSD + patents license that was previously used by React.

Creating a frontend project is easy with the help of scaffolding tools and boilerplates. Among the available choices is create-react-app, a React bootstrapping utility that takes care the laborious tasks of setting up a React project without much intervention about how the project should be structured. Given this nature, create-react-app is less assumed a boilerplate and more of a toolkit. Continue reading