void exp_sum(double *e, double *f, int e_size, int f_size)
{
for(int i = 0; i < f_size; i++)
{
grow_exp(e + i, f[i], e + i, e_size);
}
}
/* Written by Mikko Korpela */
SEXP sens1(SEXP x){
SEXP ans;
size_t i, n;
dplr_double sum, previous, this, term;
double *x_const;
listnode tmp, *tmp_p;
n = dplRlength(x);
ans = PROTECT(allocVector(REALSXP, 1));
if(n < 2){
REAL(ans)[0] = R_NaN;
UNPROTECT(1);
return ans;
}
/* Note: x must be a numeric vector */
x_const = REAL(x);
/* Setup for grow_exp */
tmp.next = NULL;
tmp.valid = FALSE;
tmp_p = &tmp;
for(i = 1; i < n; i++){
previous = x_const[i-1];
this = x_const[i];
term = (this>previous?this-previous:previous-this)/(this+previous);
if(!ISNAN(((double)term)))
grow_exp(tmp_p, term);
}
/* Sum of scaled absolute differences */
sum = 0.0f;
while(tmp_p != NULL && tmp_p->valid == TRUE){
sum += tmp_p->data;
tmp_p = tmp_p->next;
}
REAL(ans)[0] = (sum+sum)/(n-1);
UNPROTECT(1);
return ans;
}
/* Written by Mikko Korpela */
SEXP sens2(SEXP x){
SEXP ans;
size_t i, n;
double previous, this, next;
double *x_const;
dplr_double sum1, sum2;
listnode tmp, *tmp_p;
n = dplRlength(x);
ans = PROTECT(allocVector(REALSXP, 1));
if(n < 2){
REAL(ans)[0] = R_NaN;
UNPROTECT(1);
return ans;
}
/* Note: x must be a numeric vector */
x_const = REAL(x);
/* Setup for grow_exp and msum */
tmp.next = NULL;
tmp.valid = FALSE;
tmp_p = &tmp;
/* In the sum of absolute differences between consecutive elements
of an array, each number will appear multiplied by -2, -1, 0,
1, or 2 (first and last number by -1, 0, or 1) */
this = x_const[0];
next = x_const[1];
if(this > next){
grow_exp(tmp_p, this);
} else if(this < next){
grow_exp(tmp_p, -this);
}
for(i = 1; i < n-1; i++){
previous = x_const[i-1];
this = x_const[i];
next = x_const[i+1];
if(this > previous){
if(this > next){
grow_exp(tmp_p, this);
grow_exp(tmp_p, this);
} else if(this == next){
grow_exp(tmp_p, this);
}
} else if(this < previous){
if(this < next){
grow_exp(tmp_p, -this);
grow_exp(tmp_p, -this);
} else if(this == next){
grow_exp(tmp_p, -this);
}
} else if(this > next){
grow_exp(tmp_p, this);
} else if(this < next){
grow_exp(tmp_p, -this);
}
}
this = x_const[n-1];
previous = x_const[n-2];
if(this > previous){
grow_exp(tmp_p, this);
} else if(this < previous){
grow_exp(tmp_p, -this);
}
/* Sum of absolute differences */
sum1 = 0.0f;
while(tmp_p != NULL && tmp_p->valid == TRUE){
sum1 += tmp_p->data;
tmp_p = tmp_p->next;
}
sum2 = msum(x_const, n, &tmp);
REAL(ans)[0] = sum1/(sum2-sum2/n);
UNPROTECT(1);
return ans;
}
/* Written by Mikko Korpela */
void gini(double *x_const, int *n_ptr, double *result){
int i;
double *x;
long double sum1, sum2, this_x;
listnode *tmp1, *tmp2;
int n = *n_ptr;
if(n<2){
*result = 0;
return;
}
/* Sort the numbers */
x = (double *) R_alloc(n, sizeof(double));
for(i=0;i<n;i++)
x[i] = x_const[i];
R_qsort(x, 1, n);
/* Setup for grow_exp */
tmp1 = (listnode *) R_alloc(1, sizeof(listnode));
tmp1->next = NULL;
tmp1->data = (long double)x[0];
tmp1->valid = 1;
/* Cumulative sum */
for(i=1;i<n;i++){
grow_exp(tmp1, (long double)x[i]);
tmp2 = tmp1;
sum1 = 0;
while(tmp2 && tmp2->valid){
sum1 += tmp2->data;
tmp2 = tmp2->next;
}
x[i] = (double)sum1;
}
/* Setup for grow_exp */
if(tmp1->next)
tmp1->next->valid = 0;
tmp2 = (listnode *) R_alloc(1, sizeof(listnode));
tmp2->next = NULL;
/* Gini */
tmp1->data = (long double)x[n-1] * (n-1);
tmp2->data = (long double)x[0];
tmp2->valid = 1;
grow_exp(tmp2, (long double)x[0]);
for(i=1;i<n-1;i++){
this_x = (long double)x[i];
grow_exp(tmp1, this_x * i);
grow_exp(tmp2, this_x * (i+2));
}
sum1 = 0;
while(tmp1 && tmp1->valid){
sum1 += tmp1->data;
tmp1 = tmp1->next;
}
sum2 = 0;
while(tmp2 && tmp2->valid){
sum2 += tmp2->data;
tmp2 = tmp2->next;
}
*result = (double)((sum1-sum2)/((long double)x[n-1]*n));
}
