Origin Ver. 8.5 and Service Release (Select Help-->About Origin): SR5
Operating System: Windows XP
I am trying to use NLSF to fit an ordinary differential equation using the NAG functions d02pvc and d02pdc in Origin C. I did a test-drive in code-builder and got it to work, so when I gave it a try it in NLSF as follows (where t and d are the independent and dependent variable, respectively):
#pragma warning(error : 15618)
#include <origin.h>
// Add your special include files here.
// For example, if you want to fit with functions from the NAG library,
// add the header file for the NAG functions here.
#include <OC_nag8.h>
// Add code here for other Origin C functions that you want to define in this file,
// and access in your fitting function.
#define NEQ 1 // number of differential equations
struct user // parameters in the differential equations
{
double k, rt; // lowercase to avoid conflict with parameters in NLSF
};
// In addition, by Nag_User struct you can also pass in the parameters for the system
static void NAG_CALL f_callback(Integer neq, double t, double y[], double yp[], Nag_User *comm)
{
struct user *sp = (struct user *)(comm->p);
double k, rt; // temp variable
k = sp->k;
rt = sp->rt;
yp[0] = (y[0] - rt)/(2*y[0] - rt - t - k);
}
// You can access C functions defined in other files, if those files are loaded and compiled
// in your workspace, and the functions have been prototyped in a header file that you have
// included above.
// You can access NLSF object methods and properties directly in your function code.
// You should follow C-language syntax in defining your function.
// For instance, if your parameter name is P1, you cannot use p1 in your function code.
// When using fractions, remember that integer division such as 1/2 is equal to 0, and not 0.5
// Use 0.5 or 1/2.0 to get the correct value.
// For more information and examples, please refer to the "User-Defined Fitting Function"
// section of the Origin Help file.
//----------------------------------------------------------
//
void _nlsfITC11binding(
// Fit Parameter(s):
double Rt, double K,
// Independent Variable(s):
double Lt,
// Dependent Variable(s):
double& d)
{
// Beginning of editable part
Integer neq;
Nag_RK_method method;
double hstart, tstart, tend, tnow, tol;
double thres[NEQ], ynow[NEQ], ygot[NEQ], ypnow[NEQ], ymax[NEQ], ypgot[NEQ], ystart[NEQ];
Nag_ErrorAssess errass;
Nag_ODE_RK opt;
static NagError fail;
// Parameters passed to integrand by Nag_User communication struct
Nag_User comm;
struct user s;
s.k = K; // the parameters of the differential equation systems is passed through this Nag_User communication struct
s.rt = Rt;
comm.p = (Pointer)&s; // you can define your own parametrized differential equation system through this way
/* Set initial conditions and input for d02pvc */
neq = NEQ; // number of differential equations
tstart = 1e-10; // span of the time interval (the independant variable) for the solution
tend = t;
ystart[0] = 0; // initial values
thres[0] = 1.0e-9;
errass = Nag_ErrorAssess_off;
hstart = 0; // 0 value means first step size automatic
method = Nag_RK_7_8; // choose 2_3, 4_5, or 7_8
tol = 1.0e-9;
d02pvc(neq, tstart, ystart, tend, tol, thres, method, Nag_RK_onestep, errass, hstart, &opt, NAGERR_DEFAULT); // setup function need to be called to call the solver d02pcc
do
{
d02pdc(neq, f_callback, &tnow, ynow, ypnow, &opt, &comm, NAGERR_DEFAULT);//&fail);
} while (tnow<tend);
d = ypnow[0];
d02ppc(&opt); // need to call this to free some internal memory used by NAG
// End of editable part
}
It gives me these errors in my NAG_CALL f_callback function:
Error, Function argument neq is not used inside the function body
Error, Function argument y is not used inside the function body
Error, Function argument yp is not used inside the function body
Error, error(s) found in compiling function f_callback
I don't understand what my mistake is. neq is required for f_callback according to the NAG manual and I am using y and yp in the function body. I am particularly confused because all of this works outside NLSF. I'd appreciate any insight, and I apologize for the long code!
Thanks in advance,
Gregory |
Problem using NAG function in NLSF
Posted - 08/26/2009 : 8:31:44 PM
