Hermite插值法

相关的理论请参考相关的数值算法的书籍,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.

Hermite插值法结合了函数的导数值,使得插值的精度更为提高:

 

void hermite3(Type* xList,Type* yList,Type* yPList,Type x,FILE* outputFile)

{

       Type h;/*The tween value*/

       Type hAns;/*The return answer*/

             

       assertF(xList!=NULL,"in Hermite Insert xList passed in is null/n");

       assertF(yList!=NULL,"in Hermite Insert yList passed in is null/n");

       assertF(yPList!=NULL,"in Hermite Insert yPList passed in is null/n");

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

       /*Init data*/

       hAns=0;

       /*Core Program*/

       h=xList[1]-xList[0];

       hAns+=(x-xList[1])*(x-xList[1])*(h+2*(x-xList[0]))*yList[0]/(h*h*h);

       hAns+=(x-xList[0])*(x-xList[0])*(h+2*(xList[1]-x))*yList[1]/(h*h*h);

       hAns+=(x-xList[1])*(x-xList[1])*(x-xList[0])*yPList[0]/(h*h);

       hAns+=(x-xList[0])*(x-xList[0])*(x-xList[1])*yPList[1]/(h*h);

       /*End of Core Program*/

       /*Output Answer*/

       printf("the answer of hermit 3 poly is:%f/n",hAns);

       fprintf(outputFile,"the answer of hermit 3 poly is:%f/r/n",hAns);

}

 

#include "MyAssert.h"

#include "InsertAlgorithm.h"

#include <time.h>

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

 

char *inFileName="inputData.txt";

/*

       input data specification

       len,

       x0,x1,

       y0,y1,

       y0',y1',

       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*/

       Type* xList,* yList,* yPList;

       Type x;

       int len;

      

       /*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");

      

       fscanf(inputFile,"%d,",&len);

       /*Memory apply*/

       xList=(Type*)malloc(sizeof(Type)*len);

       yList=(Type*)malloc(sizeof(Type)*len);

       yPList=(Type*)malloc(sizeof(Type)*len);

       /*Read info data*/

       fscanf(inputFile,"%f,%f,",&xList[0],&xList[1]);

       fscanf(inputFile,"%f,%f,",&yList[0],&yList[1]);

       fscanf(inputFile,"%f,%f,",&yPList[0],&yPList[1]);

       fscanf(inputFile,"%f,",&x);

       printf("read in data info:%f,%f,%f,%f,%f,%f,%f/n",xList[0],xList[1],yList[0],yList[1],yPList[0],yPList[1],x);

      

#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*************/

              hermite3(xList,yList,yPList,x,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

       free(yPList);

       free(yList);

       free(xList);

       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;

}
 
原文地址:https://www.cnblogs.com/rainbowzc/p/2422319.html