Other user invoked subroutines

Besides the main subroutines there are other subroutines that the user can use to define input windows, compute statistics and compute the Hessian matrix. These are JNSEFI, JNSTAT, JNHESS and JNHEIG.

Furthermore, the subroutine JNTDEC is a ``test-deck'' used to test the program on different platforms.

• SUBROUTINE JNSEFI(ILA,I1,I2,J1,J2,NO)
  Switches off ( NO 0) or on ( NO > 0) the updating of weights between nodes I1 to I2 in layer ILA and nodes J1 to J2 in layer ILA-1. The input layer has number 0. If NO=0 the weights are set to zero and if NO=1 the weights are reinitialized. This choice of enabling/disabling can be used for selective input fields or for training only portions of the network. Selective input fields means that a hidden node only sees a portion of the input pattern, which is not identical to using receptive fields.

• SUBROUTINE JNSTAT(IS)
  Writes out information about the network on file number MSTJN(6).
  IS=1 gives a header and number of nodes in each layer (done automatically when the network is initialized).
  IS=2 gives the switches and parameters used in common block /JNDAT1/ and /JNDAT2/.
  IS=3 writes out an approximate time factor and the effective number of weights in the net.
  IS=4 writes out the Hessian matrix.
  IS=5 writes out the diagonal elements of the Hessian matrix.

• SUBROUTINE JNHESS
  Computes the upper diagonal of the Hessian, assuming a summed square error, for the training pattern currently stored in OIN and OUT. After MSTJN(2)*MSTJN(9) calls, the Hessian is normalized and the upper diagonal copied onto the lower diagonal.

• SUBROUTINE JNHEIG(IGRAD)
  Diagonalizes the Hessian matrix and computes its eigenvalues. The eigenvalues of the Hessian are placed in the vector OUT. If IGRAD 0 then the eigenvectors are computed and placed in the columns of the Hessian matrix (stored in the internal common block /JNINT5/). JNHEIG stops and writes out an error message if the Hessian is asymmetric, i.e. if JNHESS has not been presented with the full training set (no more and no less) before JNHEIG is called.

• SUBROUTINE JNTDEC(METHOD)
  A ``test deck'' that automatically tests JETNET 3.0. To check whether JETNET 3.0 is properly installed on your computer, just invoke this subroutine. It trains a feed-forward network to separate two overlapping Gaussian distributions. Which method to use is set by the switch METHOD.