Yearly Archives: 2017

Some tips about Tensorflow

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Q: How to fix error report like

A: We can’t feed a value into a variable and optimize it in the same time (So the problem only occurs when using Optimizers). Should using ‘tf.assign()’ in graph to give value to tf.Variable Q: How to get a tensor by name?… Read more »

How to average gradients in Tensorflow

Sometimes, we need to average an array of gradients in deep learning model. Fortunately, Tensorflow divided models into fine-grained tensors and operations, therefore it’s not difficult to implement gradients average by using it. Let’s see the code from github:

We should keep in mind that these codes will only… Read more »

A basic example of using Tensorflow to regress

In theory of Deep Learning, even a network with single hidden layer could represent any function of mathematics. To verify it, I write a Tensorflow example as below:

In this code, it was trying to regress to a number from its own sine-value and cosine-value. At first running, the… Read more »

Fix Resnet-101 model in example of MXNET

SSD(Single Shot MultiBox Detector) is the fastest method in object-detection task (Another detector YOLO, is a little bit slower than SSD). In the source code of MXNET,there is an example for SSD implementation. I test it by using different models: inceptionv3, resnet-50, resnet-101 etc. and find a weird phenomenon: the… Read more »

Use Mxnet To Classify Images Of Birds (Fourth Episode)

More than half a year past since previous article. In this period, Alan Mei (my old ex-colleague) collected more than 1 million pictures of Chinese Avians. And after Alexnet, VGG19, I finally chose Resnet-18 as my DNN model to classify different kinds of Chinese birds. Resnet-18 model has far less… Read more »

Using Spark-SQL to transfer CSV file to Parquet

After downloading data from “Food and Agriculture Organization of United Nations”, I get many CSV files. One of the file is named “Trade_Crops_Livestock_E_All_Data_(Normalized).csv” and it looks like:

To load this CSV file into Spark and dump it to Parquet format, I wrote these codes:

The build.sbt is

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Importance of function’s return Type in Scala

The Scala code is below:

But the output of this section of code is:

Nothing, just a pair of parenthesis. What happen? Why doesn’t Scala use the ‘call’ function in subclass ‘Student’? The answer is: we forget to define the return Type of function ‘call’, so its default… Read more »