RSERVE: Running an R Script

How to:

You can use the RSERVE function in a COMPUTE command to run an R script that returns vector output. This requires that you have a configured Adapter for Rserve.

Syntax: How to Run an R Script 

RSERVE(rserve_mf, input_field1, ...input_fieldn, output)

where:

rserve_mf

Is the synonym for the R script.

input_field1, ...input_fieldn

Are the independent variables used by the R script.

output

Is the dependent variable returned by the R script. It must be a single column (vector) of output.

Example: Using RSERVE to Run an R Script

The R script named wine_run_model.R predicts Bordeaux wine prices based on the average growing season temperature, the amount of rain during the harvest season, the amount of rain during the winter, and the age of the wine.

Using a configured connection (named MyRserve) for the Adapter for Rserve, and a sample data file named wine_input_sample.csv, you create the following synonym for the R script, as described in the Adapter Administration manual.

Master File

FILENAME=WINE_RUN_MODEL, SUFFIX=RSERVE  , $
  SEGMENT=INPUT_DATA, SEGTYPE=S0, $
    FIELDNAME=AGST, ALIAS=AGST, USAGE=D9.4, ACTUAL=STRING,
      MISSING=ON,
      TITLE='AGST', $
    FIELDNAME=HARVESTRAIN, ALIAS=HarvestRain, USAGE=I11, ACTUAL=STRING,
      MISSING=ON,
      TITLE='HarvestRain', $
    FIELDNAME=WINTERRAIN, ALIAS=WinterRain, USAGE=I11, ACTUAL=STRING,
      MISSING=ON,
      TITLE='WinterRain', $
    FIELDNAME=AGE, ALIAS=Age, USAGE=I11, ACTUAL=STRING,
      MISSING=ON,
      TITLE='Age', $
  SEGMENT=OUTPUT_DATA, SEGTYPE=U, PARENT=INPUT_DATA, $
    FIELDNAME=PRICE, ALIAS=Price, USAGE=D18.14, ACTUAL=STRING,
      MISSING=ON,
      TITLE='Price', $

Access File

SEGNAME=INPUT_DATA, 
  CONNECTION=MyRserve, 
  R_SCRIPT=/prediction/wine_run_model.r, 
  R_SCRIPT_LOCATION=WFRS, 
  R_INPUT_SAMPLE_DAT=prediction/wine_input_sample.csv, $

Now that the synonym has been created for the model, the model will be used to run against the following data file named wine_forecast.csv. 

Year,Price,WinterRain,AGST,HarvestRain,Age,FrancePop
1952,7.495,600,17.1167,160,31,43183.569
1953,8.0393,690,16.7333,80,30,43495.03
1955,7.6858,502,17.15,130,28,44217.857
1957,6.9845,420,16.1333,110,26,45152.252
1958,6.7772,582,16.4167,187,25,45653.805
1959,8.0757,485,17.4833,187,24,46128.638
1960,6.5188,763,16.4167,290,23,46583.995
1961,8.4937,830,17.3333,38,22,47128.005
1962,7.388,697,16.3,52,21,48088.673
1963,6.7127,608,15.7167,155,20,48798.99
1964,7.3094,402,17.2667,96,19,49356.943
1965,6.2518,602,15.3667,267,18,49801.821
1966,7.7443,819,16.5333,86,17,50254.966
1967,6.8398,714,16.2333,118,16,50650.406
1968,6.2435,610,16.2,292,15,51034.413
1969,6.3459,575,16.55,244,14,51470.276
1970,7.5883,622,16.6667,89,13,51918.389
1971,7.1934,551,16.7667,112,12,52431.647
1972,6.2049,536,14.9833,158,11,52894.183
1973,6.6367,376,17.0667,123,10,53332.805
1974,6.2941,574,16.3,184,9,53689.61
1975,7.292,572,16.95,171,8,53955.042
1976,7.1211,418,17.65,247,7,54159.049
1977,6.2587,821,15.5833,87,6,54378.362
1978,7.186,763,15.8167,51,5,54602.193

The data file can be any type of file that R can read. In this case it is another .csv file. This file needs a synonym in order to be used in a report request. You create the synonym for this file using the Adapter for Delimited Files.

The following is the generated Master File, wine_forecast.mas.

FILENAME=WINE_FORECAST, SUFFIX=DFIX    , CODEPAGE=1252, 
   DATASET=prediction/wine_forecast.csv, $  
SEGMENT=WINE_FORECAST, SEGTYPE=S0, $
    FIELDNAME=YEAR1, ALIAS=Year, USAGE=I6, ACTUAL=A5V,
      MISSING=ON,      TITLE='Year', $
    FIELDNAME=PRICE, ALIAS=Price, USAGE=D8.4, ACTUAL=A7V,
      MISSING=ON,      TITLE='Price', $
    FIELDNAME=WINTERRAIN, ALIAS=WinterRain, USAGE=I5, ACTUAL=A3V,
      MISSING=ON,      TITLE='WinterRain', $
    FIELDNAME=AGST, ALIAS=AGST, USAGE=D9.4, ACTUAL=A8V,
      MISSING=ON,      TITLE='AGST', $
    FIELDNAME=HARVESTRAIN, ALIAS=HarvestRain, USAGE=I5, ACTUAL=A3V,
      MISSING=ON,      TITLE='HarvestRain', $
    FIELDNAME=AGE, ALIAS=Age, USAGE=I4, ACTUAL=A2V,      MISSING=ON,      TITLE='Age', $
    FIELDNAME=FRANCEPOP, ALIAS=FrancePop, USAGE=D11.3, ACTUAL=A11V,
      MISSING=ON,      TITLE='FrancePop', $

The following is the generated Access File, wine_forecast.acx.

SEGNAME=WINE_FORECAST,   DELIMITER=',',   ENCLOSURE=",   HEADER=YES,   CDN=COMMAS_DOT,   CONNECTION=<local>, $

The following request, wine_forecast_price_report.fex, uses the RSERVE bulit-in function to run the script and return a report.

-*wine_forecast_price_report.fex
TABLE FILE PREDICTION/WINE_FORECAST
PRINT 
  YEAR
  WINTERRAIN
  AGST
  HARVESTRAIN
  AGE
     
  COMPUTE PREDICTED_PRICE/D18.2 MISSING ON ALL=
    RSERVE(prediction/wine_run_model, AGST, HARVESTRAIN, WINTERRAIN, AGE, Price);  AS 'Predicted,Price'

ON TABLE SET PAGE NOLEAD
ON TABLE SET STYLE *
GRID=OFF,$
ENDSTYLE 
END

The output is shown in the following image.