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Minimize using e04abc

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[quote][i]Originally posted by tumstudent[/i]
[br]Origin Ver. 8.5.0 SR1  
Operating System: Win7

Hi everybody,

I have a problem (very basic I assume) using originc and specifically with the function e04abc. It wants me to input a "Function" to minimize - but what kind of object is that? It seems not to be happy when I just type in the name of a funtion that i defined as "double pwrerrfit(double x)" (see below). I'm not really sure whether a function in the context of minimization is something different from a method (as defined eg by my "double pwrerrfit(double x) {...}")

Many thanks in advance,
Max

[code]//  Fit a powerlaw function to data and return fit results
void fitpwrwinoct(vector tfit, vector sigfit, double &x0, double &l1, double &l2)
{
// tfit, sigfit are global variables

printf("Fit started.\n");	
	
	
	double a, b;
	double e1, e2;
	double x, f;
	int maxiter;
	Nag_Comm comm;
	static NagError fail;

e1 = 0.0; 		
	e2 = 0.0;
	a = 0.0;						
	b = 5.0;
	maxiter = 50;
	
	e04abc(pwrerrfit, e1, e2, &a, &b, maxiter, &x, &f, &comm, &fail);
	
	// now obtain coefficients of the power law fit
	vector tx;
	tx = tfit^fitx;	
	vector vc;
	fitlinear(tx, sigfit, vc);		
	l1=vc[1]; 
	l2=vc[0]; 	
	
	x0= fitx;
	printf("Fit done.\n");
	
}

// fit a powerlaw function with exponent x to t,r data   
double pwrerrfit(double x)
{
	// tfit, sigfit are global variables
	
	vector tx;
	tx = tfit^x;
	
	vector vc;
	fitlinear(tx, sigfit, vc);
	
	vector vc0, vc1;
	int nSize = tx.GetSize();
	createConstantVector(vc[0], nSize, vc0);
	createConstantVector(vc[1], nSize, vc1);
	
	vector diff, squares;
	squares = (vc0+tx*vc1-sigfit)^2;
	double sumSquares;
	squares.Sum(sumSquares);				
	
	return sumSquares;
}[/code]
[/quote]

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T O P I C R E V I E W
tumstudent	Posted - 05/28/2011 : 07:11:28 AM Origin Ver. 8.5.0 SR1 Operating System: Win7 Hi everybody, I have a problem (very basic I assume) using originc and specifically with the function e04abc. It wants me to input a "Function" to minimize - but what kind of object is that? It seems not to be happy when I just type in the name of a funtion that i defined as "double pwrerrfit(double x)" (see below). I'm not really sure whether a function in the context of minimization is something different from a method (as defined eg by my "double pwrerrfit(double x) {...}") Many thanks in advance, Max // Fit a powerlaw function to data and return fit results void fitpwrwinoct(vector tfit, vector sigfit, double &x0, double &l1, double &l2) { // tfit, sigfit are global variables printf("Fit started.\n"); double a, b; double e1, e2; double x, f; int maxiter; Nag_Comm comm; static NagError fail; e1 = 0.0; e2 = 0.0; a = 0.0; b = 5.0; maxiter = 50; e04abc(pwrerrfit, e1, e2, &a, &b, maxiter, &x, &f, &comm, &fail); // now obtain coefficients of the power law fit vector tx; tx = tfit^fitx; vector vc; fitlinear(tx, sigfit, vc); l1=vc[1]; l2=vc[0]; x0= fitx; printf("Fit done.\n"); } // fit a powerlaw function with exponent x to t,r data double pwrerrfit(double x) { // tfit, sigfit are global variables vector tx; tx = tfit^x; vector vc; fitlinear(tx, sigfit, vc); vector vc0, vc1; int nSize = tx.GetSize(); createConstantVector(vc[0], nSize, vc0); createConstantVector(vc[1], nSize, vc1); vector diff, squares; squares = (vc0+tx*vc1-sigfit)^2; double sumSquares; squares.Sum(sumSquares); return sumSquares; }
2 L A T E S T R E P L I E S (Newest First)
Penn	Posted - 05/30/2011 : 01:31:22 AM Hi, I am afraid that you have the wrong call back function for the e04abc NAG function. The prototype of the right call back function for this NAG function is: typedef void (NAG_CALL * NAG_E04ABC_FUN)(double, double , Nag_Comm ); So, the call back function double pwrerrfit(double x) you defined should be void NAG_CALL pwrerrfit(double x, double* fc, Nag_Comm* com). For more information about how to use NAG function, please refer to this page, please especially pay attention to Callback Functions section. Also, here includes some examples for how to access NAG functions. Penn
tumstudent	Posted - 05/28/2011 : 07:13:41 AM Sorry, the error I get is 110525 PowerLawVarRange.c C:\Users\Max\Desktop\E21\test power law fit\110525 PowerLawVarRange.c(269) :Error, cannot convert argument in function call C:\Users\Max\Desktop\E21\test power law fit\110525 PowerLawVarRange.c(269) :Error, general compile error C:\Users\Max\Desktop\E21\test power law fit\110525 PowerLawVarRange.c(248) :Error, error(s) found in compiling function fitpwrwinoct with a pointer to the line e04abc(pwrerrfit, e1, e2, &a, &b, maxiter, &x, &f, &comm, &fail);

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