/*标准四阶龙格,库塔公式*/

/*Made by EmilMatthew

05/8/8*/

#include "RangeKuta.h"

#include "MyAssert.h"

#include "Ulti.h"

#include <stdlib.h>

#include <stdio.h>

#include <math.h>

 

void classicRangeKuta4(Type x0,Type y0,Type xEnd,Type h,

Type (*arguF1)(Type,Type),FILE* outputFile)

{

  Type x1,y1;/*The node answer,should be print out*/

  Type k1,k2,k3,k4;/*The tween value*/

 

  int iteratorNum=0;

  int iterLimit=0;

 

  assertF(xEnd-x0>=h,"in classicRangeKuta4  xEnd-x0<h");

  assertF(arguF!=NULL,"in classicRangeKuta4 arguF is NULL");

  assertF(outputFile!=NULL,"in classicRangeKuta4 outputFile is NULL");

 

  iterLimit=(xEnd+0.1-x0)/h;

 

  fprintf(outputFile,"xn:%-12c yn:%-12c\r\n",' ',' ');

  /*Core Program*/

  while(iteratorNum<iterLimit)

  {

    x1=x0+h;

 

    k1=(*arguF1)(x0,y0,);

    k2=(*arguF1)(x0+h/2,y0+h*k1/2);

    k3=(*arguF1)(x0+h/2,y0+h*k2/2);

    k4=(*arguF1)(x0+h,y0+h*k3);

 

    y1=y0+h*(k1+2*k2+2*k3+k4)/6;

 

    fprintf(outputFile,"%-16f%-16f\r\n",x1,y1);

    x0=x1;

    y0=y1;

 

    iteratorNum++;

  }

 

  /*Output Answer*/

  fprintf(outputFile,"total iterator time is:%d\r\n",iteratorNum);

}

 

/*Test Program*/

#include "MyAssert.h"

#include "RangeKuta.h"

#include <time.h>

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

 

Type testF1(Type x,Type y);

 

char *inFileName="inputData.txt";

/*

  input data specification

  x0,xEnd means the x value is located about in [x1,x2]

  y0 is the init state of the equation,mapped with x0.

  h is the step or  the adder of x.

*/

 

char *outFileName="outputData.txt";

#define DEBUG 1

 

void main(int argc,char* argv[])

{

  FILE *inputFile;/*input file*/

  FILE *outputFile;/*output file*/

 

  double startTime,endTime,tweenTime;/*time callopsed info*/

  float x0,xEnd,y0,h;

  /*input file open*/

  if(argc>1)strcpy(inFileName,argv[1]);

  assertF((inputFile=fopen(inFileName,"rb"))!=NULL,"input file error");

  printf("input file open success\n");

 

  /*outpout file open*/

  if(argc>2)strcpy(outFileName,argv[2]);

  assertF((outputFile=fopen(outFileName,"wb"))!=NULL,"output file error");

  printf("output file open success\n");

 

  /*Read info data*/

  fscanf(inputFile,"%f,%f,%f,%f,",&x0,&y0,&xEnd,&h);

  printf("read in data info:%f,%f,%f,%f.\n",x0,y0,xEnd,h);

 

#if  DEBUG

  printf("\n*******start of test program******\n");

  printf("now is runnig,please wait...\n");

  startTime=(double)clock()/(double)CLOCKS_PER_SEC;

  /******************Core program code*************/

    classicRangeKuta4(x0,y0,xEnd,h,&testF1,outputFile);

  /******************End of Core program**********/

  endTime=(double)clock()/(double)CLOCKS_PER_SEC;

  tweenTime=endTime-startTime;/*Get the time collapsed*/

  /*Time collapsed output*/

  printf("the collapsed time in this algorithm implement is:%f\n",tweenTime);

  fprintf(outputFile,"the collapsed time in this algorithm implement is:%f\r\n",tweenTime);

  printf("\n*******end of test program******\n");

#endif

 

  printf("program end successfully,\n you have to preess any key to clean the buffer area to output,otherwise,you wiil not get the total answer.\n");

  getchar();/*Screen Delay Control*/

  return;

}

 

Type testF1(Type x,Type y)

{

  return y-2*x/y;

}