Origin Ver. and Service Release (Select Help-->About Origin): 8.1SR3
Operating System: WinXP
I would be very grateful if someone could help me with the following problem:
I am fitting :
my function has three fitting parameters: R, L, I0
the code is as follows:
#pragma warning(error : 15618)
#include <origin.h>
#include <oc_nag8.h>
struct user
{
double R, L, fitX;
};
static double NAG_CALL f_callback(double alfa, Nag_User *comm)
{
struct user *sp = (struct user *)(comm->p);
double R_2,L_2, fitX, Rdependent, Ldependent,cylinder;
R_2=sp->R;
L_2=sp->L;
fitX=sp->fitX;
Rdependent=2*J1(fitX*R_2*sin(alfa))/(fitX*R_2*sin(alfa));
Ldependent=sin(0.5*fitX*L_2*cos(alfa))/(fitX*L_2*cos(alfa));
cylinder=Rdependent*Ldependent*Rdependent*Ldependent*sin(alfa);
return (cylinder);
}
//----------------------------------------------------------
//
void _nlsfCylinderFormFactor(
// Fit Parameter(s):
double I0, double R, double L,
// Independent Variable(s):
double x,
// Dependent Variable(s):
double& y)
{
// Beginning of editable part
double epsabs = 0.00001, epsrel = 0.0000001, result, abserr;
Integer max_num_subint = 100;
Nag_QuadProgress qp;
static NagError fail;
Nag_User comm;
struct user s;
s.R = R;
s.L = L;
s.fitX = x;
comm.p = (Pointer)&s;
d01sjc(f_callback, 0.0, PI/2.0, epsabs, epsrel, max_num_subint, &result, &abserr, &qp, &comm, &fail);
if (fail.code != NE_INT_ARG_LT && fail.code != NE_BAD_PARAM && fail.code != NE_ALLOC_FAIL)
{
NAG_FREE(qp.sub_int_beg_pts);
NAG_FREE(qp.sub_int_end_pts);
NAG_FREE(qp.sub_int_result);
NAG_FREE(qp.sub_int_error);
}
y = I0*result;
}
I am using integrator d01sjc to integrate f_callback over all alpha range, and it works very well. Now, I would like to introduce function w(L) so that the total fitting expression is:
How should I do it? I would be grateful for any suggestions, but a code example would be best. |
Double integration using NAG and d01sjc
Posted - 12/16/2010 : 11:02:05 AM
