code: public SDVariable leakyRelu(String name, SDVariable x, double alpha) {
          validateFloatingPoint("leaky ReLU", x);
          SDVariable result = f().leakyRelu(x, alpha);
          return updateVariableNameAndReference(result, name);
      }
docs: Element-wise leaky ReLU function:<br>
  out = x if x >= 0.0<br>
  out = alpha * x if x < cutoff<br>
  Alpha value is most commonly set to 0.01
  
  @param x     Input variable
  @param alpha Cutoff - usually 0.0
  @return Output variable