Using a link list over an array.

Hi, I am wondering which of the two data structures (link list or
array) would be better in my situation. I have to create a list of
rays for my ray tracing program.

the data structure of ray looks like this:


typedef struct
{
vector origin; /* vector is an array of 3 doubles */
vector efield;
double t;
vector direction;
}ray;

I need a very fine grid of rays i.e. something like 15-20 millions of
such rays. Many a times my program fails and reports less memory when
I use an array because there are data structures to be stored as well.

with an array eg. raylist[some_size] when i trace the rays, i do the
following :

for(count = 0; count < numberofrays; count++)
{
/* trace the ray raylist[i] */
}

I realized that once a ray was traced, it had no further use in the
program so it was unnecessarily occupying that memory which can be
utilized elsewhere.

I was thinking that using a link list may help my situation a little
bit here.

ray *p;
ray *q;
p = ray_list_head_ptr; /* ray_list_head_ptr points to the first node
in link list */

while( p != NULL)
{
/* trace the ray pointed by p */
q = p;
p = p->next;
/* Now the ray pointed by q is of no use so free that memory and
make the node pointed by p as the first node of the ray list */
free(q);
ray_list_head_ptr = p;
}
.

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