scripts/utils/splitXY-dummy.dml

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# Utility script to split X into new X and Y, which can be used for machine learning 
# algorithms with response variables. This script has the same functionality as splitXY.dml but also
# handles the case of dummycoded Y variables, where they may have multiple columns. 
#
# Parameters:
#    X       : (input)  filename of data matrix
#    S       : (input, default ncol(x) - N+1) starting index of dummycoding 
#    N	     : (input, default 1) number of features present (i.e. dummycoded columns)
#    OX      : (output) filename of output matrix with all columns except y
#    OY      : (output) filename of output matrix with y column
#    ofmt    : (default binary) format of OX and OY output matrix
#
# Example:
#   hadoop jar SystemML.jar -f algorithms/utils/splitXY-dummy.dml -nvargs X="/tmp/X.mtx" S=4 N=3 OX=/tmp/OX.mtx OY=/tmp/OY.mtx ofmt=csv 
#


ofmt = ifdef($ofmt, "binary")
X = read ($X)
N = ifdef($N, 1)
nc = ncol(X)
S = ifdef($S, nc-N+1) 

if (S==1)
{
    OX = X[,N+1:nc]
    OY = X[,1:N]
}
else if (S == nc-N+1) 
{
    OX = X[,1:nc-N]
    OY = X[,nc-N+1:nc]
}
else 
{
    OX1 = X[,1:S-1]
    OX2 = X[,S+N:nc]
    OX = append (OX1, OX2)
    OY = X[,S:S+N-1]
}

# Write output
write (OX, $OX, format=ofmt)
write (OY, $OY, format=ofmt)