The objective function is increased rather than decreased when fmincon is used

Dear all, I used fmincon to solve an optimization problem. Interior-point algorithm was used with TolFun=-4. The question is: Is the results below reasonable (because the objective function is increased rather than decreased), and is TolFun=-4 an acceptable value to find the minimum objective? Thanks for all in advance

                                           First-order      Norm of
 Iter F-count            f(x)  Feasibility   optimality         step
    0       1   1.267119e+002   8.249e+000   7.573e+002
    1       2   9.455037e+001   6.315e+000   3.974e+003   2.653e+001
    2       3   8.079296e+001   5.386e+000   6.179e+003   1.298e+001
    3       4   5.834199e+001   3.707e+000   1.178e+004   2.289e+001
    4       5   5.356883e+001   3.329e+000   1.292e+004   4.986e+000
    5       6   4.863383e+001   2.918e+000   1.421e+004   5.409e+000
    6       7   2.315582e+001   2.419e-001   2.146e+004   3.541e+001
    7       8   1.922367e+001   5.531e-002   2.510e+004   7.018e+000
    8       9   1.652829e+001   8.892e-004   2.683e+004   4.761e+000
    9      10   1.616538e+001   7.628e-003   2.993e+004   2.088e+000
   10      12   1.574222e+001   3.441e-003   3.491e+004   2.900e+000
   11      16   1.557995e+001   1.141e-002   3.871e+004   2.239e+000
   12      20   1.551844e+001   2.017e-002   4.293e+004   2.490e+000
   13      24   1.557486e+001   3.004e-002   4.752e+004   2.789e+000
   14      28   1.573355e+001   3.907e-002   5.202e+004   2.950e+000
   15      32   1.597043e+001   4.763e-002   5.613e+004   3.059e+000
   16      36   1.624597e+001   5.369e-002   5.952e+004   3.035e+000
   17      40   1.653425e+001   5.491e-002   6.202e+004   2.925e+000
   18      44   1.680591e+001   5.332e-002   6.360e+004   2.691e+000
   19      46   1.623598e+001   6.386e-002   6.254e+004   4.629e+000
   20      47   1.731452e+001   2.031e-002   6.420e+004   3.053e+000
   21      48   1.743835e+001   1.663e-002   6.411e+004   1.504e+000
   22      49   1.753599e+001   2.050e-002   6.349e+004   3.083e+000
   23      53   1.754284e+001   2.141e-002   6.300e+004   1.890e+000
   24      58   1.755710e+001   2.295e-002   6.248e+004   1.577e+000
   25      62   1.764624e+001   2.902e-002   6.145e+004   2.612e+000
   26      64   1.730761e+001   2.459e-002   5.757e+004   6.899e+000
   27      65   1.725259e+001   1.371e-002   5.634e+004   9.723e-001
   28      67   1.739285e+001   1.757e-002   5.439e+004   3.704e+000
   29      68   1.709089e+001   1.630e-003   5.361e+004   1.107e+000
   30      70   1.689795e+001   3.910e-003   5.214e+004   2.514e+000

                                            First-order      Norm of
 Iter F-count            f(x)  Feasibility   optimality         step
   31      72   1.673228e+001   5.134e-003   1.391e+004   2.509e+000
   32      74   1.663905e+001   5.796e-003   2.161e+004   2.714e+000
   33      76   1.669077e+001   4.075e-003   1.947e+004   2.208e+000
   34      78   1.686107e+001   3.313e-003   1.709e+004   2.066e+000
   35      80   1.711979e+001   3.118e-003   1.637e+004   1.830e+000
   36      82   1.745226e+001   2.712e-003   1.357e+004   1.657e+000
   37      84   1.780765e+001   1.861e-003   1.186e+004   1.408e+000
   38      86   1.811605e+001   8.373e-004   1.103e+004   1.085e+000
   39      88   1.833220e+001   2.629e-004   1.164e+004   7.627e-001
   40      90   1.847421e+001   9.214e-005   1.640e+004   5.617e-001
   41      92   1.858397e+001   6.522e-005   1.938e+004   5.205e-001
   42      94   1.868685e+001   9.598e-005   1.227e+004   5.935e-001
   43      96   1.879185e+001   1.758e-004   1.066e+004   7.100e-001
   44      98   1.889754e+001   2.661e-004   1.074e+004   7.827e-001
   45     100   1.900088e+001   2.984e-004   1.766e+004   7.824e-001
   46     102   1.910188e+001   2.788e-004   2.294e+004   7.395e-001
   47     104   1.920181e+001   2.373e-004   1.605e+004   6.773e-001
   48     106   1.930109e+001   1.881e-004   9.666e+003   6.062e-001
   49     108   1.939901e+001   1.452e-004   3.851e+003   5.345e-001
   50     110   1.949428e+001   1.115e-004   1.397e+003   4.681e-001
   51     112   1.958544e+001   8.493e-005   6.107e+003   4.092e-001
   52     114   1.967122e+001   6.331e-005   1.033e+004   3.580e-001
   53     116   1.975091e+001   4.592e-005   1.411e+004   3.150e-001
   54     118   1.982469e+001   3.284e-005   1.755e+004   2.809e-001
   55     120   1.989361e+001   2.432e-005   2.073e+004   2.564e-001
   56     122   1.995917e+001   1.897e-005   2.377e+004   2.409e-001
   57     124   2.002281e+001   1.594e-005   2.675e+004   2.324e-001
   58     126   2.008554e+001   1.441e-005   2.973e+004   2.279e-001
   59     128   2.014770e+001   1.363e-005   3.271e+004   2.242e-001
   60     130   2.020914e+001   1.304e-005   3.567e+004   2.193e-001

                                            First-order      Norm of
 Iter F-count            f(x)  Feasibility   optimality         step
   61     132   2.026951e+001   1.230e-005   3.859e+004   2.127e-001
   62     134   2.032859e+001   1.133e-005   4.146e+004   2.054e-001
   63     136   2.038643e+001   1.025e-005   4.426e+004   1.985e-001
   64     138   2.044324e+001   9.177e-006   4.703e+004   1.929e-001
   65     140   2.049919e+001   8.202e-006   4.977e+004   1.883e-001
   66     142   2.055409e+001   7.328e-006   5.247e+004   1.834e-001
   67     144   2.060718e+001   6.505e-006   5.511e+004   1.762e-001
   68     146   2.065701e+001   5.662e-006   5.761e+004   1.645e-001
   69     148   2.070174e+001   4.755e-006   5.988e+004   1.472e-001
   70     150   2.073966e+001   3.779e-006   6.181e+004   1.249e-001
   71     152   2.076983e+001   2.780e-006   6.338e+004   9.997e-002
   72     156   2.077587e+001   1.556e-006   6.369e+004   2.011e-002
   73     166   2.077452e+001   1.139e-007   4.386e+000   3.843e-004
   74     172   2.077322e+001   1.484e-009   4.614e-002   2.886e-003

Local minimum found that satisfies the constraints.

Optimization completed because the objective function is non-decreasing in feasible directions, to within the selected value of the function tolerance, and constraints are satisfied to within the default value of the constraint tolerance.

criteria details

Answer 1

[Torsten]

You must not only look at the "f(x)"-column, but also at the "feasibility" column.

What is a "solution" good for if it is not feasible ?

Best wishes

Torsten.

[Muna Shehan]

Thanks for your response, I understand your explanation, but when I tried to increase TolFun=-5, I get different exitflag (2) and different message and the results is shown below. Can you suggest any thing to increase the possibility to change the exit message from (Local minimum possible. Constraints satisfied minimum ) to (Local minimum found that satisfies the constraints.)

    >> addpath(fullfile(pwd, 'solver'))

Direct Transcription
                                            First-order      Norm of
 Iter F-count            f(x)  Feasibility   optimality         step
    0       1   1.267119e+002   8.249e+000   7.573e+002
    1       2   9.455037e+001   6.315e+000   3.974e+003   2.653e+001
    2       3   8.079296e+001   5.386e+000   6.179e+003   1.298e+001
    3       4   5.834199e+001   3.707e+000   1.178e+004   2.289e+001
    4       5   5.356883e+001   3.329e+000   1.292e+004   4.986e+000
    5       6   4.863383e+001   2.918e+000   1.421e+004   5.409e+000
    6       7   2.315582e+001   2.419e-001   2.146e+004   3.541e+001
    7       8   1.922367e+001   5.531e-002   2.510e+004   7.018e+000
    8       9   1.652829e+001   8.892e-004   2.683e+004   4.761e+000
    9      10   1.616538e+001   7.628e-003   2.993e+004   2.088e+000
   10      12   1.574222e+001   3.441e-003   3.491e+004   2.900e+000
   11      16   1.557995e+001   1.141e-002   3.871e+004   2.239e+000
   12      20   1.551844e+001   2.017e-002   4.293e+004   2.490e+000
   13      24   1.557486e+001   3.004e-002   4.752e+004   2.789e+000
   14      28   1.573355e+001   3.907e-002   5.202e+004   2.950e+000
   15      32   1.597043e+001   4.763e-002   5.613e+004   3.059e+000
   16      36   1.624597e+001   5.369e-002   5.952e+004   3.035e+000
   17      40   1.653425e+001   5.491e-002   6.202e+004   2.925e+000
   18      44   1.680591e+001   5.332e-002   6.360e+004   2.691e+000
   19      46   1.623598e+001   6.386e-002   6.254e+004   4.629e+000
   20      47   1.731452e+001   2.031e-002   6.420e+004   3.053e+000
   21      48   1.743835e+001   1.663e-002   6.411e+004   1.504e+000
   22      49   1.753599e+001   2.050e-002   6.349e+004   3.083e+000
   23      53   1.754284e+001   2.141e-002   6.300e+004   1.890e+000
   24      58   1.755710e+001   2.295e-002   6.248e+004   1.577e+000
   25      62   1.764624e+001   2.902e-002   6.145e+004   2.612e+000
   26      64   1.730761e+001   2.459e-002   5.757e+004   6.899e+000
   27      65   1.725259e+001   1.371e-002   5.634e+004   9.723e-001
   28      67   1.739285e+001   1.757e-002   5.439e+004   3.704e+000
   29      68   1.709089e+001   1.630e-003   5.361e+004   1.107e+000
   30      70   1.689795e+001   3.910e-003   5.214e+004   2.514e+000

                                              First-order      Norm of
   Iter F-count            f(x)  Feasibility   optimality         step
     31      72   1.673228e+001   5.134e-003   1.391e+004   2.509e+000
     32      74   1.663905e+001   5.796e-003   2.161e+004   2.714e+000
     33      76   1.669077e+001   4.075e-003   1.947e+004   2.208e+000
     34      78   1.686107e+001   3.313e-003   1.709e+004   2.066e+000
     35      80   1.711979e+001   3.118e-003   1.637e+004   1.830e+000
     36      82   1.745226e+001   2.712e-003   1.357e+004   1.657e+000
     37      84   1.780765e+001   1.861e-003   1.186e+004   1.408e+000
     38      86   1.811605e+001   8.373e-004   1.103e+004   1.085e+000
     39      88   1.833220e+001   2.629e-004   1.164e+004   7.627e-001
     40      90   1.847421e+001   9.214e-005   1.640e+004   5.617e-001
     41      92   1.858397e+001   6.522e-005   1.938e+004   5.205e-001
     42      94   1.868685e+001   9.598e-005   1.227e+004   5.935e-001
     43      96   1.879185e+001   1.758e-004   1.066e+004   7.100e-001
     44      98   1.889754e+001   2.661e-004   1.074e+004   7.827e-001
     45     100   1.900088e+001   2.984e-004   1.766e+004   7.824e-001
     46     102   1.910188e+001   2.788e-004   2.294e+004   7.395e-001
     47     104   1.920181e+001   2.373e-004   1.605e+004   6.773e-001
     48     106   1.930109e+001   1.881e-004   9.666e+003   6.062e-001
     49     108   1.939901e+001   1.452e-004   3.851e+003   5.345e-001
     50     110   1.949428e+001   1.115e-004   1.397e+003   4.681e-001
     51     112   1.958544e+001   8.493e-005   6.107e+003   4.092e-001
     52     114   1.967122e+001   6.331e-005   1.033e+004   3.580e-001
     53     116   1.975091e+001   4.592e-005   1.411e+004   3.150e-001
     54     118   1.982469e+001   3.284e-005   1.755e+004   2.809e-001
     55     120   1.989361e+001   2.432e-005   2.073e+004   2.564e-001
     56     122   1.995917e+001   1.897e-005   2.377e+004   2.409e-001
     57     124   2.002281e+001   1.594e-005   2.675e+004   2.324e-001
     58     126   2.008554e+001   1.441e-005   2.973e+004   2.279e-001
     59     128   2.014770e+001   1.363e-005   3.271e+004   2.242e-001
     60     130   2.020914e+001   1.304e-005   3.567e+004   2.193e-001

                                              First-order      Norm of
   Iter F-count            f(x)  Feasibility   optimality         step
     61     132   2.026951e+001   1.230e-005   3.859e+004   2.127e-001
     62     134   2.032859e+001   1.133e-005   4.146e+004   2.054e-001
     63     136   2.038643e+001   1.025e-005   4.426e+004   1.985e-001
     64     138   2.044324e+001   9.177e-006   4.703e+004   1.929e-001
     65     140   2.049919e+001   8.202e-006   4.977e+004   1.883e-001
     66     142   2.055409e+001   7.328e-006   5.247e+004   1.834e-001
     67     144   2.060718e+001   6.505e-006   5.511e+004   1.762e-001
     68     146   2.065701e+001   5.662e-006   5.761e+004   1.645e-001
     69     148   2.070174e+001   4.755e-006   5.988e+004   1.472e-001
     70     150   2.073966e+001   3.779e-006   6.181e+004   1.249e-001
     71     152   2.076983e+001   2.780e-006   6.338e+004   9.997e-002
     72     156   2.077587e+001   1.556e-006   6.369e+004   2.011e-002
     73     166   2.077452e+001   1.139e-007   4.386e+000   3.843e-004
     74     172   2.077322e+001   1.484e-009   4.614e-002   2.886e-003
     75     196   2.077322e+001   1.101e-009   4.614e-002   2.385e-005
     76     203   2.077322e+001   5.689e-010   4.614e-002   7.720e-006
     77     210   2.077322e+001   2.857e-010   4.614e-002   3.854e-006
     78     217   2.077322e+001   1.428e-010   4.614e-002   1.926e-006
     79     224   2.077322e+001   7.141e-011   4.614e-002   9.630e-007
     80     231   2.077322e+001   3.571e-011   4.614e-002   4.815e-007
     81     238   2.077322e+001   1.785e-011   4.614e-002   2.407e-007
     82     245   2.077322e+001   8.925e-012   4.614e-002   1.204e-007
     83     252   2.077322e+001   4.463e-012   4.614e-002   6.018e-008
     84     259   2.077322e+001   2.232e-012   4.614e-002   3.009e-008
     85     266   2.077322e+001   1.116e-012   4.614e-002   1.505e-008
     86     273   2.077322e+001   5.585e-013   4.614e-002   7.523e-009
     87     280   2.077322e+001   2.786e-013   4.614e-002   3.761e-009

Local minimum possible. Constraints satisfied.

fmincon stopped because the size of the current step is less than
the default value of the step size tolerance and constraints are 
satisfied to within the default value of the constraint tolerance.

<stopping criteria details>

, please.

BestRegards