Messages
Some of the more common messages and codes passed by CLP are listed in the
tables below. This is list is not meant to exhaustive. The notation is as
for printf from "C":
%s is a string
%d is an integer
%g or %f
is a floating point value
COIN Messages passed at or above logging level 1
Code
Area
Text and notes

1
MPSREAD
At line %d %s

This just prints out NAME line, ROW line, etc

2
MPSREAD
Problem %s has %d rows, %d columns and %d elements

This gives statistics after reading an MPS file

8
MPSREAD
%s read with %d errors

This gives error statistics for file

505
PRESOLVE
Presolved poblem not optimal, resolve after postsolve

This could be because it was not feasible or because of maximum
iterations. If this message occurs then consider using primal clean up

506
PRESOLVE
Presolve %d (%d) rows, %d (%d) columns and %d (%d) elements

The first number is the number after presolve and the number
in parentheses is amount of reduction

510
PRESOLVE
Presolve is modifying %d integer bounds and re-presolving

If presolve determines at the end that an integer variable have its bounds
changed then it will repeat the entrire presolve

511
PRESOLVE
After Postsolve, objective %g, infeasibilities - dual %g (%d),
primal %g (%d)

This gives the state after postsolve - this gives the objective value
and the sum of dual and primal infeasibilities with the number of
infeasibilities in parentheses. Hopefully these should be zero

512
PRESOLVE
Presolved model was optimal, full model needs cleaning up

If the numbers in previous message (511) were large then maybe we need to
know, if small then that's life

CLP Messages passed at or above logging level 1
Code
Area
Text and notes

0
SIMPLEX
Optimal - objective value %g

The only message you want to see

1
SIMPLEX
Primal infeasible - objective value %g

You may need to look at previous messages or use methods. Such as
sumPrimalInfeasibilities() to find cause

2
SIMPLEX
Dual infeasible - objective value %g

You may need to look at previous messages or use methods. Such as
sumDualInfeasibilities() to find cause

3
SIMPLEX
Stopped - objective value %g

The algorithm stopped as requested by the user.

4
SIMPLEX
Stopped due to errors - objective value %g

Switch on log level 2 to see information on size of elements etc. If they
look reasonable then maybe we need to know.

5
SIMPLEX
%d Obj %g Primal inf %g (%d) Dual inf %g (%d)

At each re-factorization this gives the number of iterations and the value
of the objective function. If there are primal infeasibilities then the
sum and number are given and similarly for dual infeasibilities.
(This is a simplified form of message.)

14
SIMPLEX
Perturbing problem by %g % of %g

There is more to this message but if the user sees this then s/he has
chosen to perturb the problem or the algorithm has decided to do so.
If the numbers look too large the user may wish to think again.

19
SIMPLEX
%d variables/rows fixed as scaled bounds too close

If this occurs look carefully at your input data

24
SIMPLEX
Matrix will be packed to eliminate small elements

If this occurs the user should look carefully at data.

26
SIMPLEX
Matrix will be packed to eliminate %d duplicate elements

If this occurs the user should look carefully at data.

28
SIMPLEX
Crash put %d variables in basis, %d dual infeasibilities

29
SIMPLEX
End of values pass after %d iterations

??? If primal(1) or dual(1) the a sweep through model is made and this
signals end of pass.

COIN Messages passed at or above logging level 0
Code
Area
Text and notes

3001
MPSREAD
Illegal value for %s of %g

String will be "infinity" if setInfinity passed bad value,
or "default integer bound" if setDefaultBound passed bad value.

3002
MPSREAD
Bad image at line %d < %s >

This gives line number and the offending line

3003
MPSREAD
Duplicate objective at line %d < %s >

An objective row appears twice in one column

3004
MPSREAD
Duplicate row %s at line %d %s

The named row appears twice in one column.

3005
MPSREAD
No match for row %s at line %d < %s >

The named row did not appear in ROWS section.

3006
MPSREAD
No match for column at line %d < %s >

The named column (in BOUNDS section) did not appear in COLUMNS section.

6001
MPSREAD
Unable to open mps input file %s

6002
MPSREAD
Unknown image %s at line %d of file %s

The Mps reader could not make sense of the image file specified.

6003
MPSREAD
Consider the possibility of a compressed file which zlib is unable to read.

Some .gz files can not be read by zlib. Using gunzip and then gzip
normally cures problem.

6004
MPSREAD
EOF on file %s

The Mps reader did not find expected section marker.

6005
MPSREAD
Returning as too many errors

The reader has put out 100 messages and is giving up.

507
PRESOLVE
Presolve determined that the problem is infeasible with tolerance of %g

If you want you can try with a larger tolerance

508
PRESOLVE
Presolve thinks problem is unbounded

Perhaps the user should maximize if initially minimizing or vice versa.

509
PRESOLVE
Presolve thinks problem is infeasible AND unbounded???

If you get this message we want to know

CLP Messages passed at or above logging level 0
Code
Area
Text and notes

3002
SIMPLEX
Not solving empty problem - %d rows, %d columns and %d elements

Test problem size before solving.

6002
SIMPLEX
%d bad bound pairs or bad objectives were found

Either the value in the objective was too large or a lower bound was
greater than an upper bound.

6003
SIMPLEX
Matrix has %d large values, first at column %d, row %d is %g

Some of the values in matrix are ridiculous.

6004
SIMPLEX
Can't get out of loop ...

There are also messages available at log level 2 (the most likely useful relate
to scaling), and will be addressed in a future version of this User Guide.