code: public void setInitialLearningRate(double initialLearningRate)
      {
          if(initialLearningRate <= 0 || Double.isInfinite(initialLearningRate) || Double.isNaN(initialLearningRate))
              throw new IllegalArgumentException("Learning rate must be a positive constant, not " + initialLearningRate);
          this.initialLearningRate = initialLearningRate;
      }
docs: Sets the initial learning rate to use for the first epoch. The learning
  rate will decay according to the
  {@link #setLearningRateDecay(jsat.math.decayrates.DecayRate) decay rate}
  in use.
  
  @param initialLearningRate the initial learning rate to use