RS01200: CPLEX'S MATLAB CONNECTOR IMPROPERLY DOUBLES THE OFF DIAGONAL ELEMENTS OF THE MATRIX IN A QUADRATIC CONSTRAINT.

APAR status

• Closed as fixed if next.

Error description

• Can be seen from the following sequence of MATLAB connector
  commands, assuming the LP file has at least one quadratic
  constraint.
  
  >> cpx = Cplex('LPfile_problem');
  >> cpx.readModel(['qcp.lp']);
  >> full(cpx.Model.qc(1).Q)
  ans =
  1.0e+07 *
  0.000000102689830 0.000285043398990
  0.000285043398990 1.582430103240310
  >> cpx.writeModel(['qcp1.lp']);
  >> cpx.readModel(['qcp1.lp']);
  >> full(cpx.Model.qc(1).Q)
  ans =
  1.0e+07 *
  0.000000102689830 0.000570086797980
  0.000570086797980 1.582430103240310
  
  Defect logged in RTC-13719
  

Local fix

• No simple workaround available.  Problem exists in all
  versions up to
  and including 12.5.0.0, but has not been encountered externally,
  probably because MATLAB users rarely input models from files.
  
  Fixed in 12.5.0.1.
  

Problem summary

• MATLAB connector doesn't properly input Q matrix in quadratic
  constraint, multiplying the values by 2, when reading model from
  a LP, MPS or SAV file.
  

Problem conclusion

Temporary fix

• None; fortunately this is infrequently used functionality in
  MATLAB.   Fixed in 12.5.0.1
  

Comments

APAR Information

• APAR is sysrouted FROM one or more of the following:

• APAR is sysrouted TO one or more of the following:

Fix information

Applicable component levels

• RC50 PSY

     UP