Vector math with Streaming Expressions?

[Eric Pugh]

I’m trying to average three arrays of floats and not quite making the 
conceptual jump from “I defined a array of numbers” in the way that the 
https://github.com/apache/lucene-solr/blob/visual-guide/solr/solr-ref-guide/src/vector-math.adoc#element-by-element-vector-math
 example expects with “I made a query and get back a array of numbers”. 
I’m using the films example, so :  bin/solr start -c -e films

Then, I want to get the vectors for three films and average them.   

The streaming expression grabs the three vectors, but I can’t figure out how to 
wrap it in something to average them.

select(      
  search(films,
        qt="/select",
        q="name:"Finding Nemo" OR name:"Bee Movie" OR name:"Harry Potter and 
the Chamber of Secrets"",
        fl="id,name,film_vector"),
  film_vector
  )

produces:

{
  "result-set": {
    "docs": [
      {
        "film_vector": [
          "-0.2758314",
          "-0.14416906",
          "-0.11316811",
          "0.2745105",
          "0.040616427",
          "-4.2628963E-4",
          "-0.120363355",
          "0.07888852",
          "0.036417373",
          "-0.29541242"
        ]
      },
      {
        "film_vector": [
          "-0.11665395",
          "0.04247921",
          "-0.13233364",
          "0.52578413",
          "-0.1739291",
          "-0.01880563",
          "-0.06670809",
          "-0.11242808",
          "0.09724514",
          "-0.11909142"
        ]
      },
      {
        "film_vector": [
          "-0.14272659",
          "0.13051921",
          "-0.19087574",
          "0.44983688",
          "-0.21098459",
          "0.0033124345",
          "-0.008155139",
          "-0.09109363",
          "0.12401622",
          "-0.12211737"
        ]
      },
      {
        "EOF": true,
        "RESPONSE_TIME": 24
      }
    ]
  }
}

Great, now how do I average across them and get the final vector that I expect, 
which should be similar to:

[-0.1784, 0.0096, -0.1455, 0.4167, -0.1148, -0.0053, -0.0651, -0.0415, 0.0859, 
-0.1789]

Thanks!

Eric

_______________________
Eric Pugh | Founder & CEO | OpenSource Connections, LLC | 434.466.1467 | 
http://www.opensourceconnections.com <http://www.opensourceconnections.com/> | 
My Free/Busy <http://tinyurl.com/eric-cal>  
Co-Author: Apache Solr Enterprise Search Server, 3rd Ed 
<https://www.packtpub.com/big-data-and-business-intelligence/apache-solr-enterprise-search-server-third-edition-raw>
    
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