Shell window

The window of the shell from which SNNS is invoked is used for the output of protocol messages.

These protocols include:

• Messages about the success or failure of the loading or saving of a file.

• Informations about the settings of SNNS when the button in the remote panel is pressed.

• Error messages of the pattern file parser when the pattern file does not correspond to required grammar.

• Learning errors (see below)

• Validation set errors

When learning is started, the error of the output units is reported on this window after each epoch, i.e. after the presentation of all patterns.

To save the window from being flooded on longer training runs, the maximum number of reported errors is limited to 10. Therefore, when 20 learning cycles are specified, the error gets printed only after every other cycle. This error report has the following form:

  Learning all patterns:
    epochs   : 100
    parameter:  0.80000
    #o-units : 26
    #patterns: 26

     epoch:         SSE            MSE            SSE/o-units

Train  100:      57.78724        2.22259           2.22259
Train   90:      24.67467        0.94903           0.94903
Train   80:      23.73399        0.91285           0.91285
Train   70:      22.40005        0.86154           0.86154
Train   60:      20.42843        0.78571           0.78571
Train   50:      18.30172        0.70391           0.70391
Test    50:      25.34673        0.97487           0.97487
Train   40:      16.57888        0.63765           0.63765
Train   30:      14.84296        0.57088           0.57088
Train   20:      12.97301        0.49896           0.49896
Train   10:      11.22209        0.43162           0.43162
Train    1:      10.03500        0.38596           0.38596
Test     1:      11.13500        0.42696           0.42696

The first line reports whether all or only a single pattern is trained. The next lines give the number of specified cycles and the given learning parameters, followed by a brief setup description.

Then the 10-row-table of the learning progress is given. If validation is turned on this table is intermixed with the output of the validation. The first column specifies whether the displayed error is computed on the training or validation pattern set, ``Test'' is printed for the latter case. The second column gives the number of epochs still to be processed. The third column is the SSE of the learning function. The exact computation of this value depends on the definition in the learning algorithm, but usually the sum of the squared differences between target output and actual output is used. The forth column is the MSE, which is the first value divided by the number of patterns. The fifth value finally gives the SSE divided by the number of output units. The second and third values are equal if there are as many patterns as there are output units (e.g. the letters application), the first and third values are identical, if the network has only one output unit (e.g. the xor network).

If the training of the network is interrupted by pressing the button in the remote panel, the values for the last completed training cycle are reported.