ReadonlycostObjective coefficients, length count.
ReadonlycountNumber of represented columns.
ReadonlylowerLower bounds, length count.
ReadonlymatrixCoefficients with numCols === count and rows matching the model.
ReadonlyupperUpper bounds, length count.
Detached selected-column data in ascending model-index order. The matrix is CSC with
numCols === countand one row per current model row.