  maximal fractional branching  Select an integer variable from the solution of the relaxed subproblem with largest distance from next integer value. 
  minimal fractional branching  Select an integer variable from the solution of the relaxed subproblem with smallest distance from next integer value. 
  best of two  The optimal objective function values of the two child nodes are compared and the node with a lower value is chosen. If both are leafs, i.e., if the corresponding solution is integral, or if the corresponding problem is infeasible or if there is already a better integral solution, strategy best of all is started. 
  best of all  Select an integer variable from the solution of the relaxed subproblem with smallest distance from next integer value. 
  depth first  Selects a child node whenever possible. If the node is a leaf the best of all strategy is applied. 
The corresponding continuous relaxed problems are solved by
the FORTRAN 77 code QL, an implementation of a primaldual method.
The internal matrix transformations are performed in numerically
stable way. A special variant of the branchandbound solver BFOUR is included.



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