#include <stdio.h>
#include <stdlib.h>
#include <math.h>
typedef double (*func_t)(double);
double function1(double x)
{
return 2*sin(x)-0.5;
}
double function2(double x)
{
return 2*cos(x);
}
typedef struct values_s
{
double *arg;
double * funcval ;
long size ;
} values_t ;
typedef enum boolean_e
{
FALSE = 0,
TRUE = 1
} boolean_t ;
values_t * values_allocate (long size )
{
values_t *elem;
if(!(elem=calloc(1,sizeof(values_t))))
{
fprintf(stderr,"Fehler bei Speicherallozierung!\n");
return 0;
}
if(!(elem->arg=calloc(size,sizeof(double))))
{
fprintf(stderr,"Fehler bei Speicherallozierung!\n");
free(elem);
return 0;
}
if(!(elem->funcval=calloc(size,sizeof(double))))
{
fprintf(stderr,"Fehler bei Speicherallozierung!\n");
free(elem->arg);
free(elem);
return 0;
}
elem->size=size;
return elem;
}
boolean_t values_insert ( values_t *val , double arg , double value , long index )
{
if(!val||index<0||index>=val->size)
return FALSE;
val->arg[index]=arg;
val->funcval[index]=value;
return TRUE;
}
boolean_t values_free ( values_t *val)
{
if(!val)
return FALSE;
free(val->arg);
val->arg=0;
free(val->funcval);
val->funcval=0;
free(val);
//val=0;
return TRUE;
}
boolean_t values_print ( values_t *val)
{
if(!val)
return FALSE;
long i;
for(i=0;i<val->size;i++)
printf("%ld: %10g %10g\n",i,val->arg[i],val->funcval[i]);
return TRUE;
}
double newton_step (double x0 , func_t func , func_t derivate )
{
if(!derivate(x0))
{
fprintf(stderr,"Division durch 0!\n");
return x0;
}
return x0-func(x0)/derivate(x0);
}
boolean_t newton_iter(values_t *val, double x0, double genauigkeit, double schritte, func_t func, func_t derivate)
{
if(!val)
return FALSE;
long i;
for(i=0;i<val->size&&i<schritte;i++)
{
values_insert(val,x0,func(x0),i);
if(fabs(func(x0))<genauigkeit)//absoluter Wert von func(x0)
break;
x0=newton_step(x0,func,derivate);
}
return TRUE;
}
boolean_t values_store(values_t *val,char *file)
{
if(!val)
return FALSE;
FILE *f;
if(!(f=fopen(file,"w")))
return FALSE;
long i;
for(i=0;i<val->size;i++)
fprintf(f,"%ld: %10g %10g\n",i,val->arg[i],val->funcval[i]);
fclose(f);
return TRUE;
}
int main()
{
printf("Newton-Verfahren!\n");
values_t *elem;
double x0=3;
double genauigkeit = 0.0001;
elem=values_allocate(5);
newton_iter(elem,x0,genauigkeit,elem->size,function1,function2);
values_print(elem);
if(values_store(elem,"test.txt")!=TRUE)
fprintf(stderr,"Fehler beim Speichern!\n");
if(values_free(elem)!=TRUE)
{
fprintf(stderr,"Fehler bei Speicherfreigabe!\n");
exit(-1);
}
elem=0;
return 0;
}
