Error in matlab stratified cross validation partitioning "CVPARTITION can have at most one optional argument"

I am trying to perform stratified cross validation as the data is highly imbalanced. The output labels of the data are in the matrix predictionMatrix. It is a 832*1 dimensional matrix with values 0/1. For cross validation, I am using the function cvpartition, but it is generating the error:

CVPARTITION can have at most one optional argument

The code is:

c = cvpartition(predictionMatrix,'KFold',5,'Stratify',true);

1 Answer

You must be using an older version of MATLAB. For example, in MATLAB release R2016a, the cvpartition command takes only one pair of optional arguments as in

c = cvpartition(predictionMatrix,'KFold',5)

and the option ...'Stratify',true is not available at all. So you would get the same error as yours:

I = randi(100,832,1);
predictionMatrix = (I>50);
c = cvpartition(predictionMatrix,'KFold',5,'Stratify',true); Error using cvpartition (line 130) CVPARTITION can have at most one optional argument

However, in MATLAB release R2018a and beyond, the same code works just fine:

I = randi(100,832,1);
predictionMatrix = (I>50);
c = cvpartition(predictionMatrix,'KFold',5,'Stratify',true)
c =
K-fold cross validation partition NumObservations: 832 NumTestSets: 5 TrainSize: 666 665 665 666 666 TestSize: 166 167 167 166 166