#include "header.h"

int objfun(vec x,float *f,vec *df,mat *ddf,con spec)//spec shows what kind of value are we evaluating.
{
	int i,j;
	float sum=0;
	float tmp;
	if(spec.f==1)           // spec.f==1 means to evaluate the value of function
	{
		for(i=1;i<x.n-1;i++)
		{
			sum+=(float)sin(x.fp[i]*x.fp[i+1]+cos(x.fp[i-1]-x.fp[i])); 
		}
		*f=sum;
		printf("f=:%f\n",*f);
	}
	if(spec.df==1)           // spec.df==1 means to find the derivarive value which is a vector
	{
		for(i=0;i<x.n;i++)
		{       
 			tmp=-cos(x.fp[i+1]*x.fp[i+2]+cos(x.fp[i]-x.fp[i+1]))*sin(x.fp[i]-x.fp[i+1])*((float)(i<=x.n-3))+cos(x.fp[i]*x.fp[i+1]+cos(x.fp[i-1]-x.fp[i]))*(x.fp[i+1]+sin(x.fp[i-1]-x.fp[i]))*((float)(i>=1&&i<=x.n-2))+cos(x.fp[i-1]*x.fp[i]+cos(x.fp[i-2]-x.fp[i-1]))*x.fp[i-1]*((float)(i>=2));	//since some of the item missing in some i, so i use the boolean function to decide if the item appers of not.
		  df->fp[i]=tmp;  	
		}
	}
	if(spec.ddf==1)           // spec.ddf==1 means to get the value of second derivative function which is a matrix
	{
		for(i=0;i<x.n;i++)
		{
			for(j=0;j<x.n;j++)//i is the column number and j row number
			{		
				if(j<i-2||j>i+2)tmp=0;//The derivative of f only contains x_{i-2} to x_{i+2}, hence the variales out of this range will lead the second derivative equal to 0.
                                if(j==i-2) tmp=(x.fp[j+1]*sin(x.fp[j] - x.fp[j+1])*sin(x.fp[j+1]*x.fp[j+2] + cos(x.fp[j] - x.fp[j+1])))*(i>=2);
				if(j==i-1) tmp=(cos(x.fp[j] - x.fp[j+1])*cos(x.fp[j+1]*x.fp[j+2]+cos(x.fp[j]-x.fp[j+1]))+sin(x.fp[j] - x.fp[j+1])*(x.fp[j+2]+sin(x.fp[j] - x.fp[j+1]))*sin(x.fp[j+1]*x.fp[j+2] + cos(x.fp[j] - x.fp[j+1])))*(i>=1&&i<=x.n-2)+(cos(x.fp[j]*x.fp[j+1]+cos(x.fp[j-1]-x.fp[j]))-x.fp[j]*(x.fp[j+1] + sin(x.fp[j-1] - x.fp[j]))*sin(x.fp[j]*x.fp[j+1] + cos(x.fp[j-1] - x.fp[j])))*(i>=2);
				if(j==i) tmp=(-(cos(x.fp[j]-x.fp[j+1])*cos(x.fp[j+1]*x.fp[j+2]+cos(x.fp[j]-x.fp[j+1])))-pow(sin(x.fp[j]-x.fp[j+1]),2)*sin(x.fp[j+1]*x.fp[j+2]+cos(x.fp[j]-x.fp[j+1])))*(i<=x.n-3)+(-(cos(x.fp[j-1] - x.fp[j])*cos(x.fp[j]*x.fp[j+1] + cos(x.fp[j-1] - x.fp[j])))-pow(x.fp[j+1]+sin(x.fp[j-1] - x.fp[j]),2)*sin(x.fp[j]*x.fp[j+1] + cos(x.fp[j-1] - x.fp[j])))*(i>=1&&i<=x.n-2)+(-(pow(x.fp[j-1],2)*sin(x.fp[j-1]*x.fp[j] + cos(x.fp[j-2] - x.fp[j-1]))))*(i>=2);
				if(j==i+1) tmp=(cos(x.fp[j-1] - x.fp[j])*cos(x.fp[j]*x.fp[j+1] + cos(x.fp[j-1] - x.fp[j])) +sin(x.fp[j-1] - x.fp[j])*(x.fp[j+1] + sin(x.fp[j-2] - x.fp[j-1]))*sin(x.fp[j]*x.fp[j+1]+ cos(x.fp[j-1] - x.fp[j])))*(i<=x.n-3)+(cos(x.fp[j-1]*x.fp[j]+cos(x.fp[j-2] - x.fp[j-1]))-x.fp[j-1]*(x.fp[j] + sin(x.fp[j-2] - x.fp[j-1]))*sin(x.fp[j-1]*x.fp[j] + cos(x.fp[j-2] - x.fp[j-1])))*(i>=1&&i<=x.n-2);
				if(j==i+2) tmp=(x.fp[j-1]*sin(x.fp[j-2] - x.fp[j-1])*sin(x.fp[j-1]*x.fp[j] + cos(x.fp[j-2] - x.fp[j-1])))*(i<=x.n-3);// these second derivative are all made by the software mathematicas.
			ddf->fp[j*x.n+i]=tmp;	
			}
		
	}}
	return 0;
}