相关的理论请参考数值计算相关书籍，我这里只给出关键的函数及主程序段，其余相关的细节就不再一一罗列了.
/*Core Function*/
#include "FindRoot.h"
#include "MyAssert.h"
#include "Ulti.h"
#include <stdlib.h>
#include <stdio.h>
#include <math.h>
void jieXianMethod(Type x1,Type x2,double e,Type (*arguF)(Type),FILE* outputFile)
{
Type x;/*The return answer*/
Type y,y1,y2;/*The tween answer*/
int iteratorNum=0;
assertF(x1<=x2,"in jieXianMethod x1>=x2");
assertF(arguF!=NULL,"in jieXianMethod arguF is NULL");
assertF(outputFile!=NULL,"in jieXianMethod outputFile is NULL");
assertF((*arguF)(x1)*(*arguF)(x2)<=0,"in jieXianMethod,f(x1)*f(x2)>0");
/*Core Program*/
do
{
x=(x1*(*arguF)(x2)-x2*(*arguF)(x1))/((*arguF)(x2)-(*arguF)(x1));
y=(*arguF)(x);
y1=(*arguF)(x1);
if(y*y1>=0)
{
x1=x;y1=y;
}
else
{
x2=x;y2=y;
}
fprintf(outputFile,"x1:%-12f x2:%-12f y:%-12f\r\n",x1,x2,y);
iteratorNum++;
}
while(fabs(y)>e);
/*Output Answer*/
fprintf(outputFile,"total iterator time is:%d\r\n",iteratorNum);
fprintf(outputFile,"a root of equation is :%f\r\n",x);
}
/*Main Test Program*/
#include "MyAssert.h"
#include "FindRoot.h"
#include <time.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
Type testF(Type argu);
char *inFileName="inputData.txt";
/*
input data specification
x1,x2 means the root is located about in [x1,x2]
e is the limitation of the control answer
*/
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 x1,x2,e;
/*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,",&x1,&x2,&e);
printf("read in data info:%f,%f,%f.\n",x1,x2,e);
#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*************/
jieXianMethod(x1,x2,e,&testF,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 testF(Type x)
{
return x*x*x-5*x*x+16*x-80;
}
测试数据:
输入inputData.txt:
2,6,0.0001,
输出:outputData.txt:
x1:4.142857 x2:6.000000 y:-28.425657
x1:4.799246 x2:6.000000 y:-7.835989
x1:4.956494 x2:6.000000 y:-1.764906
x1:4.990748 x2:6.000000 y:-0.378460
x1:4.998041 x2:6.000000 y:-0.080294
x1:4.999585 x2:6.000000 y:-0.017007
x1:4.999912 x2:6.000000 y:-0.003597
x1:4.999981 x2:6.000000 y:-0.000782
x1:4.999996 x2:6.000000 y:-0.000156
x1:5.000000 x2:6.000000 y:-0.000020
total iterator time is:10
a root of equation is :5.000000
the collapsed time in this algorithm implement is:0.000000
