quad.c

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#include "mesh1D.h"

/* Composite midpoint rule */
double quadPM(double (*f)(double), double *X, int N, double h){
  int i;
  double S=0.;
  PRINT_VERBOSE("->");
  for (i=0;i<N-1;i++)
    S+=f((X[i]+X[i+1])/2.); /* Not an efficient way but it's closed to the formula*/
  PRINT_VERBOSE("<-");
  return S*h;
}

double quadPMAlloc(double (*f)(double), double a, double b, int N, double *ph){
  int i;
  double *X,S=0.;
  PRINT_VERBOSE("->");
  DisRegAlloc(a,b,N,&X,ph);
  for (i=0;i<N-1;i++)
    S+=f((X[i]+X[i+1])/2.);
  free(X);
  PRINT_VERBOSE("<-");
  return S*(*ph);
}