CPLEX ignores 'mipdisplay'

[4er4er4er]

The mipdisplay option isn't causing a MIP log to be displayed in CPLEX MP. For example, using a MIP from the AMPL book with 'mipdisplay=2':

ampl: model multmip3.mod;
ampl: data multmip3.dat;
ampl: option solver cplex;
ampl: option cplex_options 'mipdisplay=2';
ampl: solve;
CPLEX 22.1.1:   tech:mipdisplay = 2
CPLEX 22.1.1: optimal solution; objective 235625
101 simplex iterations
ampl: 

It's the same for any other setting of mipdisplay. The option 'outlev=1' does work for MP, but it is harder to read:

ampl: option cplex_options 'outlev=1';
ampl: solve;
CPLEX 22.1.1:   tech:outlev = 1
 - Version identifier: 22.1.1.0 | 2022-11-27 | 9160aff4d
 - CPXPARAM_MIP_Display                             3
 - Tried aggregator 1 time.
 - MIP Presolve eliminated 6 rows and 9 columns.
 - MIP Presolve modified 13 coefficients.

Besides the extraneous dash before each line, 'outlev=1' sets 'mipdisplay=3' which can make the log a lot harder to read:

 - 
        Nodes                                         Cuts/
 -    Node  Left     Objective  IInf  Best Integer    Best Bound    ItCnt     Gap

 - *     0+    0                        12112.0000        0.0000           100.00%
 - Found incumbent of value 12112.000000 after 0.02 sec. (2.44 ticks)
 - *     0+    0                        10474.0000        0.0000           100.00%
 - Found incumbent of value 10474.000000 after 0.02 sec. (2.45 ticks)
 -       0     0      265.6000    25    10474.0000      265.6000       40   97.46%
 - *     0+    0                          345.0000      265.6000            23.01%
 - Found incumbent of value 345.000000 after 0.02 sec. (3.30 ticks)
 -       0     0      265.6000    29      345.0000       Cuts: 6       58   23.01%
 -       0     0      266.0000     4      345.0000      Fract: 1       60   22.90%
 - *     0+    0                          289.0000      266.0000             7.96%
 - Found incumbent of value 289.000000 after 0.03 sec. (12.02 ticks)
 - *     0+    0                          275.0000      266.0000             3.27%
 - Found incumbent of value 275.000000 after 0.06 sec. (12.69 ticks)
 - *     0+    0                          271.0000      266.0000             1.85%
 - Found incumbent of value 271.000000 after 0.08 sec. (16.47 ticks)
 -       0     0  -1.00000e+75     0      271.0000      266.0000       60    1.85%
 - Detecting symmetries...
 -       0     2      266.0000     4      271.0000      266.0000       60    1.85%
 - Elapsed time = 0.09 sec. (18.02 ticks, tree = 0.02 MB, solutions = 6)
 - *    23+    1                          269.0000      266.0000             1.12%
 - Found incumbent of value 269.000000 after 0.11 sec. (22.42 ticks)
 - *  1940   823      integral     0      268.0000      266.0000     9271    0.75%
 - Found incumbent of value 268.000000 after 0.33 sec. (99.45 ticks)
 - *  2205   762      integral     0      266.0000      266.0000    11767    0.00%
 - Found incumbent of value 266.000000 after 0.34 sec. (108.70 ticks)

I recommend having 'outlev=1' set 'mipdisplay=2' instead.