Installing Theano and CUDA on Mac OS X

I started trying Theano today and wanted to use the GPU (NVIDIA GeForce GT 750M 2048 MB) on my Mac. Here’s a brief instruction on how to use the GPU on Mac, largely following the instructions from

Install Theano:

Download and install CUDA:

Put the following lines into your ~/.bash_profile:

Note that the PATH line is necessary. Otherwise you may see the following message:

ERROR (theano.sandbox.cuda): nvcc compiler not found on $PATH. Check your nvcc installation and try again.

Configure Theano:

Test if GPU is used:

A more realistic example:

So it seems this GPU does not outperform the CPU. Well,GT 750M may not be the best GPU you can get… Someone else here has a similar experience.


Raspberry Pi as a toy web server

1. Tell my router to route certain traffic to the Raspberry Pi. For example, I route HTTP and SSH traffic to one of my Pi’s. I disabled password login for  SSH, using public key authentication instead: in /etc/ssh/sshd_config, use the following setting and restart SSH service using `sudo service ssh restart’.

2. Getting my IP address of the Raspberry Pi. I firstly created a PHP script on my domain to record the IP address in a text file.

Then tell the Raspberry Pi to report its IP address every 5 minutes, using crontab:

After a while the IP address is recorded in the text file and updated every 5 minutes.

3. Optionally create a DNS record for the Pi. I use Cloudflare to manage DNS settings by myself, so just add/update an entry in Cloudflare’s settings. I point to the IP address of one Pi. This can be done automatically in the future.

4. Install Flask on the Pi.

5. Install nginx and uwsgi on the Pi.

6. Set up nginx along with uwsgi and Flask.

Edit nginx config:

Edit uwsgi config:

Create a simple Flask app:

Start up uwsgi:

7. Done!

 Update on June 24, 2014:

Getting the external address in step 2 can be done by running this command in Raspberry Pi:


NumPy’s ndarray indexing

In NumPy a new kind of array is provided: n-dimensional array or ndarray. It’s usually fixed-sized and accepts items of the same type and size. For example, to define a 2×3 matrix:

When indexing ndarray, it supports “array indexing” other than single element indexing.  (See

It is possible to index arrays with other arrays for the purposes of selecting lists of values out of arrays into new arrays. There are two different ways of accomplishing this. One uses one or more arrays of index values. The other involves giving a boolean array of the proper shape to indicate the values to be selected. Index arrays are a very powerful tool that allow one to avoid looping over individual elements in arrays and thus greatly improve performance.

So you basically can do the following:

Besides, when you do equals operation on ndarrays, another ndarray is returned by comparing each element:

Statistics of insurance sold on on Valentine’s Day

On Feb. 14th Taobao launched a campaign to sell insurance products, which promises 7% yearly interest rate. The sales data is public, so I wrote a script to crawl them down and did a brief study on this data. Here’re the results.

On that day (actually sold out in less than two hours in total) more than 40,000 people participated, resulting a total sales of almost one billion CNY (the exact number: 980,270,000 CNY). Two companies participated in this sales campaign: Zhujiang and Tian’an. The sales statistics are:

Zhujiang Tian’an Total
# of Customers 13831 29092 42923
Sales mean (k CNY) 24.922059 21.847003 22.837872
Sales min (k CNY) 1 1 1
Sales 25% (k CNY) 1 2 2
Sales 50% (k CNY) 10 10 10
Sales 75% (k CNY) 20 25 22
Sales max (k CNY) 1000 900 1000
Sales total (k CNY) 344697 635573 980270

The histograms of how many people pay for each amount.


Zhujiang was extremely popular: in 2 minutes and 56 seconds it reached a sales of 200,212,000 CNY, that’s more than 1 million CNY sales PER SECOND! Indeed Chinese are crazy about online shopping. 😀

mod_wsgi and mod_xsendfile on OS X 10.9 Mavericks

Updated on Nov 4, 2013: The following tricks may still work, however I have found a much easier solution. Simply install Xcode command line developer tools and you should be able to compile source code without issues:

After upgrading my Mac from 10.8 to 10.9 Mavericks my apache stopped working, so I have to reinstall mod_wsgi and mod_xsendfile. However, tricks are needed to compile and install these mods successfully.

Upgrade Xcode

Upgrade Xcode in App Store. As mentioned by Valerie:

I had to manually upgrade Xcode (after Mavericks upgrade) from the App Store & agree to its license because ./configure hung forever until I did that.


For mod_wsgi installation, create a soft link to OSX10.9.xctoolchain:

Then run configure under mod_wsgi source code directory:

It will generate a Makefile similar as follows:

However, this Makefile is not correct and running ‘make’ the compiler will complain something like:

Prepend the following line to CPPFLAGS value:

Save the Makefile and it will look something like:

Then make && install:

Modify /etc/apache2/httpd.conf to enable mod_wsgi:


Use the following command to compile and install mod_xsendfile:

Enabling HTTPS/SSL

After upgrading OS X the apache configuration was reset, but your original config is save to /etc/apache2/httpd.conf.pre-update. I need to enable SSL in httpd.conf again by uncommenting the following line:

Restart Apache and everything should work fine

Tastypie error handling with Unauthorized Exception

In Tastypie v0.9.15 unauthorized exception messages are not included in the response. The cause lies in the following code: (tastypie/, Line 601-602 in v0.9.15)

In the above snippet an empty response is returned, without including messages in exception.

In order to fix this, you can override this method in your model resources, for example:

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