Author Archives: Robin Dong

Books I read in year 2018

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In the 2018 year, I continued to learn more knowledge about machine learning and deep Learning. “Deep Learning” is pretty suitable for me and “Hands-On Machine Learning with Scikit-Learn and TensorFlow” is also a wonderful supplement for programming practice. I also learned some basic knowledge about Reinforcement learning. To teach… Read more »

Write text to file with disabling buffer in Python3

In Python2 era, we could use these code to write the file without buffer:

But in Python3 we can only write binary file by disabling buffer:

The only way to write text file without buffering is:

Adding ‘flush()’ everywhere is a terrible experience for a programmer who… Read more »

A successful rescue for a remote server

After installed CUDA-9.2 on a remote server, I found that the system can’t load nvidia.ko (kernel module) with dmesg:

The reason is the current kernel running on my system has turned on the CONFIG_CC_STACKPROTECTOR compiler option. Therefore I change the default entry of grub2 and reboot the server, for… Read more »

Some tips about python this week

List of lists in python Created a list of lists by using multiply symbol:

It’s weird that adding one item to first list have side-effect on second list! Seems ‘* 2’ makes two reference for one list. How to avoid this then? The answer is using normal syntax:

Read more »

Compare implementation of tf.AdamOptimizer to its paper

When I reviewed the implementation of Adam optimizer in tensorflow yesterday, I noticed that it’s code is different from the formulas that I saw in Adam’s paper. In tensorflow’s formulas for Adam are: But the algorithm in the paper is: Then quickly I found these words in the document of… Read more »

The bug about using hooks and MirroredStrategy in tf.estimator.Estimator

When I was using MirroedStrategy in my tf.estimator.Estimator:

and add hooks for training:

The tensorflow report errors:

Without finding any answers on google, I have to look into the code of ‘’ in tensorflow. Fortunately, the code defect is obvious:

class Estimator havn’t any private argument… Read more »

Some lessons from Kaggle’s competition

About two months ago, I joined the competition of ‘RSNA Pneumonia Detection’ in Kaggle. It’s ended yesterday, but I still have many experiences and lessons to be rethinking. 1. Augmentation is extremely crucial. After using tf.image.sample_distorted_bounding_box() in my program, the mAP(mean Average Precision) of evaluating dataset thrived to a perfect… Read more »

How could it possible to assign an integer to string?

The snippet below could be compiled and run:

The result is:

I noticed that the corresponding value of key ‘banana’ is empty. The reason is I assign an integer directly to key ‘banana’ by mistake. But how could c++ compiler allow me to do this? Why doesn’t it… Read more »

Move semantics in C++11

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After studying an example for Move Semantics of C++11, I write a more complete code snippet:

Pay attention to last two lines in ‘move constructor’:

Since ‘move constructor’ will not set initial value for m_size and m_data of ‘v4’, the m_size and m_data of ‘v3’ will be uninitial… Read more »

How Tensorflow set device for each Operation ?

In Tensorflow, we only need to use snippet below to assign a device to a Operation:

How dose it implement? Let’s take a look. There is a mechanism called ‘context manager’ in Python. For example, we can use it to add a wrapper for a few codes:

The… Read more »