PIS2

This project contains Source Codes for Perishable Inventory Systems (PIS) with Impatient Customers, Single Server, Finite/Infinite Buffer, and (S,s) policy to calculate its characteristics and steady state probabilities with innovative approximate Merged formula (by Prof. Dr. Agassi Melikov, [email protected]) and also directly solving Balance equations using Gaussian elimination algorithm.

Project Structure contains 2 main packages.

1. com.shahmaliyev.utilsM
   1.1) classes FormatterMatrixM, FormatterNumberM are used to convert text data to matrix/number and vice versa.
   1.2) class GaussianCalculator is used to solve linear equations using classical Gaussian elimination algorithm.
   1.3) class RandomGenerator is used to generate values for exponentially and Bernoulli distributed random variables.
   1.4) class SteadyState is used to calculate Steady State probabilities from balance equations.
   1.5) class MathM contains factorial function to calculate factorial for large integers.
   1.6) class UtilsM contains different practical functions (working with dates, console, formats etc.).
   1.7) class NormsCalculator contains functions to calculate different norms (Euclidean Norm, Cosine Similarity, Jaccard Similariy etc.).
   1.8) class DynamicNumber is used in whole project for number operations, it has three modes: double, bigdecimal and bigfraction, we choose required mode depending on speed, division accuracy etc, for example if we need to solve linear equations using Gaussian elimination algorithm for matrix with numerical instability (that is dividing very small decimal numbers) then we could use bigdecimal or bigfraction mode in order to prevent precision loss in intermediary divisions.

2. com.shahmaliyev.simulation.pis2 - package that contains classes associated with PIS.
   2.1) SimulationCharacteristicsPIS2 - contains functions for calculation of characteristics and steady state probabilities of given PIS.
   2.2) SimulationParametersPIS2 - defines parameters of given PIS and is passed to SimulationCharacteristicsPIS2 object.
   2.3) Example usage(in Java programming language):

   SimulationParametersPIS2 simulationParameters = new SimulationParametersPIS2();
   simulationParameters.N=150;
   simulationParameters.S=50;
   simulationParameters.gamma=2;
   simulationParameters.lyambda=30;
   simulationParameters.mu1=6;
   simulationParameters.mu2=3;
   simulationParameters.sigma1=0.7;
   simulationParameters.sigma2=0.3;
   simulationParameters.s=20;
   simulationParameters.tao=0.5;
   simulationParameters.v=1;

   SimulationCharacteristicsPIS2 sc = new SimulationCharacteristicsPIS2();
   sc.calculateConsolidation(sp, false);
   sc.calculateGaus(sp, false);

   System.out.println(sc.Sav);
   System.out.println(sc.Gav);
   System.out.println(sc.RR);
   System.out.println(sc.Lav);
   System.out.println(sc.PL);
   System.out.println(UtilsM.matrixToString(sc.p_m_n));

PS: Please also download Apache Commons Math library in order to use BigFraction class. Version used in project is 3.6.1 located in lib folder. Link for the latest version: http://commons.apache.org/proper/commons-math/download_math.cgi