An array of arrays of integers to where the row indices of the queried columns will be copied. The nonzero indices of column begin+i will be copied into an array returned as ind[i]. This array must be initialized at least to size num.
val
An array of arrays of doubles to where the nonzero coefficients of the queried columns will be copied. The nonzero values of column begin+i will be copied into an array returned as val[i]. This array must be initialized to at least size num.
Remarks
For every column, an array of row indices and an array of values is returned, corresponding to the nonzeros in the specified columns.