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Questions tagged [apache-spark]

Apache Spark is an open source cluster computing system that aims to make data analytics fast — both fast to run and fast to write, originally developed in the AMPLab at UC Berkeley.

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32 views

Random forest vs majority voting

I'm using spark with scala to implement majority voting of decision trees and random forest (both are configured in the same way - same depth, the same amount of base classifiers etc.). Dataset is ...
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14 views

Is there a Spark library for computing canonical correlation?

I can't seem to find a library for computing canonical correlation in Spark. Canonical correlation analysis (CCA) is common in other data science-focused systems. This exists in R's base and in ...
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11 views

Setting up Zeppelin to work with a Spark Cluster

I have made a spark cluster containing 2 workers and 1 master. I followed the following link to set up the spark clusters. After successfully setting up the spark clusters I wanted to connect it to ...
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0answers
10 views

Is Logistic Regression with SGD Optimization supported in the latest version of Spark ML?

LogisticRegressionWithSGD is deprecated from Spark Mllib. Is there a way to run Logistic Regression using SGD optimization under the hood, instead of LBFGS?
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1answer
24 views

Regarding join in pyspark

Given a rdd in pyspark, $A=[(0, 1), (1, 2), (1, 3), (3, 0)]$ I am trying to find self join of A such that the second element of previous pair is equal to first element of next pair i.e. $...
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1answer
23 views

How to deal with evaluations in a multi step ML pipeline

Apache Spark provides us the pipeline to construct a ML pipeline. Moreover, we can evaluate the regressors in the pipeline, now here is the point I dont understand: how to apply to testing data. Ok, ...
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0answers
12 views

How to create tensors in spark?

I have the following data stored in HDFS: each row has three columns, id, date, item, which means a person with a particular id bought a particular item on a particular date. The dataset has billions ...
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0answers
20 views

Is there a way to use a pom.xml file to update spark configuration?

I am trying to update my spark configuration to solve some dependency problems. This pom.xml file seems to be useful for this purpose. I am using a spark docker image. ...
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0answers
50 views

Pyspark: Filter dataframe based on separate specific conditions

How can I select only certain entries that match my condition and from those entries, filter again using regex? For instance, I have this dataframe (df) ...
4
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1answer
636 views

How to implement LSTM with Spark?

I would like to build an LSTM network for text classification with PySpark, but I don't find any library or function about it. ...
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2answers
43 views

Record Linkage problem

I am building Matching Alogoritm using ML.Project is to match Internal customer data with external customer data.Features are names,address,city,state and zip. We create pairs between data sets and ...
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3 views

PCAModel and PipelineModel, how to get explainedVariance

in pyspark PCAModel contains explainedVariance() method , but once you use Pipeline and specify PCA as a "stage", you will get a PipelineModel as an output and this one does not contain ...
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0answers
254 views

Spark Scala concatenate 2 different data frames

I have 2 different Spark data frames and I want to concatenate them together by columns with no join operations. How can I do it using Scala?
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35 views

Spark creating dat file - header/trailer issue

Although this is a DS community but I saw spark tag so asking query here. 0 I've a specific scenario of creating a file extract (dat/delimited) in ...
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0answers
60 views

scala spark FP-Growth no results displayed

I have implemented the FP-growth algorithm and it works fine with this sample data: r z h k p z y x w v u t s s x o n r x z y m t s q e z x z y r q t p when I ...
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0answers
11 views

Hints on my EMR Spark Cluster

I am new to Spark, in particular I am tying to find out which are the best recommended properties to set to work on a 1 master 2 slaves cluster with 10GB memory each. Do you know which are a good set ...
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0answers
24 views

In Spark, is it a must not to have executors running in Master node when running in cluster mode?

I was running my Spark application on AWS EMR, I launched a master node of m5.xlarge its CPU and RAM usages are both very low. So master node is run for Yarn and main driver to collect calculated data ...
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0answers
19 views

How do I recommend items to out of training users based on its recent views?

I used Spark's ALS implementation of matrix factorization (Collaborative Filtering for Implicit Feedback) to train user and item embeddings. Since we have a lot of users in system, I had to sample ...
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0answers
24 views

Spark: how to process tree aggregation and statistic

I have a description of file system in form of a csv: ...
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0answers
20 views

Probabilistic guarantees for SQL query execution

We are working on a project that tries to accelerate Spark SQL using dedicated hardware. Our approach works much better (in terms of the resulting latency) if we allow query processing that is only ...
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0answers
38 views

Obtain learning curve of Gradient Boosted Tree model in PySpark

Currently there seems to be no method in PySpark of checkpointing the performance of a model at each gradient update. Is there a way to get the performance of a model at each gradient update so that a ...
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2answers
65 views

Apache Spark alternatives for local compute

I am creating a relatively large hobby project in Scala that needs a few ml algorithms for text classification into topics. My dataset is not huge, it is < 500,000 items with dimensionality 5 (2 ...
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1answer
724 views

Spark DataFrame Limit Function Takes Too Much Time to Show

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0answers
139 views

What is the difference between PySpark's featuresCol, labelCol, predictionCol, and probabilityCol?

I am attempting to train a random forest classifier (pyspark.ml.classification.RandomForestClassifier) on a large dataset (~70gb). However, I am not sure what to ...
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0answers
72 views

Is plotting gain of XGBoost trees useful?

I am working on a XGBoost model for fraud detection (2 class classification) using XGBoost v0.7 on Spark. I am looking at different aspects of the model to find important features but also to ...
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1answer
196 views

Standard Scaler drops accuracy significantly in Scala Spark

I am working on Scala with Spark for a prediction model. I tried both Normalization and Standard Scaling and both of them drops my accuracy significantly. Without the accuracy is ~90% (on training ...
2
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1answer
140 views

Is there any point in learning Hadoop in 2018?

I'm a data analyst/scientist working mostly with the Python open source stack i.e. Pandas, scikit-learn, matplotlib, seaborn etc. I want to expand my toolbox and learn a distributed computing ...
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0answers
13 views

Is there a built-in pyspark function for the paradigm union(filter, take)? [closed]

Essentially, filtering by key, taking a specific number (based on key) from the DataFrame, and unioning these results for a number of values. For example, ...
2
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1answer
105 views

XGBoost most important features appear in multiple trees multiple times

I am fitting xgboost model (scala-spark) to my dataset of transactions. I have about 2 millions of transactions in my training set which is highly unbalanced with a ratio of positive/negative<0.001 ...
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1answer
51 views

Best Data Science & Machine Learning Conferences 2019? [closed]

What are the best data science conferences you have attended? I am looking for a conference that will help me further develop my Data Science and Machine Learning competencies. Topics that are ...
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2answers
57 views

Lightweight execution of Spark MLLib models

I have some training data which I am using to build a Spark MLLib model which is in a Hive database. I am using simple linear regression models and the PySpark API. I have code set up to train this ...
0
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1answer
38 views

How does “sameModel” mean in Spark ML Pipeline, (Section: Example: Pipeline), from the docs?

I'm looking at the Spark ML docs in scala for Section: Example Pipeline https://spark.apache.org/docs/latest/ml-pipeline.html#example-pipeline. From the example, the model is fit using a pipeline (...
2
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1answer
349 views

cosine similarity between items (purchase data) and normalisation

I'm using IndexedRowMatrix which represents the products's user purchase behaviours and in order to build product recommendations, I use cosine similarity to calculate similarities between products. ...
0
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1answer
734 views

Accumulators in Spark (PySpark) without global variables?

BACKGROUND Consider the following textbook example which uses accumulators to add vectors. ...
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1answer
398 views

Why am I getting the same value for the accuracy and recall when using spark's mllib's MulticlassClassificationEvaluator?

So, I am having a play around with some tree based algorithms from Spark's mllib. The code I have is here; ...
0
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1answer
2k views

PySpark: java.io.EOFException

System: 1 name node, 4 cores, 16 GB RAM 1 master node, 4 cores, 16 GB RAM 6 data nodes, 4 cores, 16 GB RAM each 6 worker nodes, 4 cores, 16 GB RAM each around 5 Terabytes of storage space The data ...
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3answers
3k views

Reliable way to verify Pyspark data frame column type

If I read data from a CSV, all the columns will be of "String" type by default. Generally, I inspect the data using the following functions which gives an overview of the data and its types ...
0
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1answer
4k views

Replacing null with average in pyspark

I have a problem during upsampling operation in PySpark. My dataframe is: ...
2
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2answers
270 views

Navigating the jungle of choices for scalable ML deployment

I have prototyped a machine learning (ML) model on my local machine and would like to scale it to both train and serve on much larger datasets than could be feasible on a single machine. (The model ...
1
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1answer
4k views

Plotting in PySpark?

I have been searching for methods to plot in PySpark. I couldn't find any resource on plotting data residing in DataFrame in PySpark. The only methods which are listed are: through method ...
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0answers
60 views

Deep Learning in Spark Clusters vs on GPUs?

What would be a better way to perform deep learning on any given task, either using Spark Clusters or by taking advantage of GPU's multiple cores. Which would give less training time and be better ...
2
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0answers
491 views

Alternative to Apache Spark? [closed]

I have been looking for a comprehensive alternative to Apache Spark for Big Data analytics/machine learning and couldn't find one. The ones which I have come across are: Apache Flink Google DataFlow ...
0
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2answers
89 views

Apache Spark Understanding

I have read a lot about Apache Spark. About RDD, DataFrames etc etc. But I haven't come across a simple explanation as to why and where should we be using Apache Spark? If my primary goal is machine/...
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0answers
51 views

Unable to open application master UI in spark1.6.1 in cluster mode

Hadoop cluster has 8 nodes with high availability of resource manager. Active ResourceManager is in node 3. and Standby ResourceManager in node 2. when i submit the application in cluster mode. the ...
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0answers
487 views

Frequent itemset vs. frequent sequence mining algorithms on variables with an inherent order

I've been using Pyspark's PrefixSpan algorithm to mine sequences of variables with an inherent order (bus stops). I know that PrefixSpan takes into consideration the order of the items it is fed, ...
4
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1answer
964 views

Why does spark.ml.feautures.Word2Vec vectorize sentences instead of single words?

In the process of understanding how Word2Vec in Spark differs from gensim one, I got very confused by the example presented in the Spark docs (reference link: https://spark.apache.org/docs/2.2.0/ml-...
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1answer
2k views

How to apply StandardScaler and OneHotEncoder simultaneously in Spark Machine learning?

I try to create a machine learning model, linear regression, to predict a price of a diamonds. All examples that I found online do not have a step with scaling of data, using MinMaxScaler or ...
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0answers
312 views

Interpreting rawPrediction from Spark ML LinearSVC

I am using Spark ML's LinearSVC in a binary classification model. The transform method creates two columns, prediction and ...
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2answers
505 views

Exponential runtime on distance matrix

I have an exploratory script running a Databricks notebook that performs a simple arithmetic function (Pythagorean theorem) on all possible pairwise combinations of a list of pairs of floats (akin to ...