∑-

This operation removes and returns the last sample from the statistics data. It expects to find a variable called ∑DAT which has a set of statistics values stored in a real matrix. Each row in the real matrix represents a single set of samples. Each column contains one of the set of values associated with a single sample. When ∑- is executed, the bottom row of values in the ∑DAT real matrix is removed and put onto the stack. If the ∑DAT matrix has a single column, the real value is pushed onto the stack. If the ∑DAT has two or more columns, then a real vector containing the values from the bottom of the ∑DAT matrix is pushed onto the stack.

After the operation finishes, the number of rows in the ∑DAT matrix is reduced by one. If there are no samples left in the ∑DAT variable, the ∑DAT variable is deleted.