void
Curve::_get_vector (double x0, double x1, float *vec, int32_t veclen)
{
double rx, lx, hx, max_x, min_x;
int32_t i;
int32_t original_veclen;
int32_t npoints;
if (veclen == 0) {
return;
}
if ((npoints = _list.events().size()) == 0) {
/* no events in list, so just fill the entire array with the default value */
for (int32_t i = 0; i < veclen; ++i) {
vec[i] = _list.default_value();
}
return;
}
if (npoints == 1) {
for (int32_t i = 0; i < veclen; ++i) {
vec[i] = _list.events().front()->value;
}
return;
}
/* events is now known not to be empty */
max_x = _list.events().back()->when;
min_x = _list.events().front()->when;
if (x0 > max_x) {
/* totally past the end - just fill the entire array with the final value */
for (int32_t i = 0; i < veclen; ++i) {
vec[i] = _list.events().back()->value;
}
return;
}
if (x1 < min_x) {
/* totally before the first event - fill the entire array with
* the initial value.
*/
for (int32_t i = 0; i < veclen; ++i) {
vec[i] = _list.events().front()->value;
}
return;
}
original_veclen = veclen;
if (x0 < min_x) {
/* fill some beginning section of the array with the
initial (used to be default) value
*/
double frac = (min_x - x0) / (x1 - x0);
int64_t fill_len = (int64_t) floor (veclen * frac);
fill_len = min (fill_len, (int64_t)veclen);
for (i = 0; i < fill_len; ++i) {
vec[i] = _list.events().front()->value;
}
veclen -= fill_len;
vec += fill_len;
}
if (veclen && x1 > max_x) {
/* fill some end section of the array with the default or final value */
double frac = (x1 - max_x) / (x1 - x0);
int64_t fill_len = (int64_t) floor (original_veclen * frac);
float val;
fill_len = min (fill_len, (int64_t)veclen);
val = _list.events().back()->value;
for (i = veclen - fill_len; i < veclen; ++i) {
vec[i] = val;
}
veclen -= fill_len;
}
lx = max (min_x, x0);
hx = min (max_x, x1);
if (npoints == 2) {
/* linear interpolation between 2 points */
/* XXX: this numerator / denominator stuff is pretty grim, but it's the only
way I could get the maths to be accurate; doing everything with pure doubles
gives ~1e-17 errors in the vec[i] computation.
*/
/* gradient of the line */
double const m_num = _list.events().back()->value - _list.events().front()->value;
double const m_den = _list.events().back()->when - _list.events().front()->when;
/* y intercept of the line */
double const c = double (_list.events().back()->value) - (m_num * _list.events().back()->when / m_den);
/* dx that we are using */
double dx_num = 0;
double dx_den = 1;
if (veclen > 1) {
dx_num = hx - lx;
dx_den = veclen - 1;
for (int i = 0; i < veclen; ++i) {
vec[i] = (lx * (m_num / m_den) + m_num * i * dx_num / (m_den * dx_den)) + c;
}
} else {
vec[0] = lx * (m_num / m_den) + c;
}
return;
}
if (_dirty) {
solve ();
}
rx = lx;
double dx = 0;
if (veclen > 1) {
dx = (hx - lx) / (veclen - 1);
}
for (i = 0; i < veclen; ++i, rx += dx) {
vec[i] = multipoint_eval (rx);
}
}
void
Curve::_get_vector (double x0, double x1, float *vec, int32_t veclen)
{
double rx, dx, lx, hx, max_x, min_x;
int32_t i;
int32_t original_veclen;
int32_t npoints;
if ((npoints = _list.events().size()) == 0) {
for (i = 0; i < veclen; ++i) {
vec[i] = _list.default_value();
}
return;
}
/* events is now known not to be empty */
max_x = _list.events().back()->when;
min_x = _list.events().front()->when;
lx = max (min_x, x0);
if (x1 < 0) {
x1 = _list.events().back()->when;
}
hx = min (max_x, x1);
original_veclen = veclen;
if (x0 < min_x) {
/* fill some beginning section of the array with the
initial (used to be default) value
*/
double frac = (min_x - x0) / (x1 - x0);
int32_t subveclen = (int32_t) floor (veclen * frac);
subveclen = min (subveclen, veclen);
for (i = 0; i < subveclen; ++i) {
vec[i] = _list.events().front()->value;
}
veclen -= subveclen;
vec += subveclen;
}
if (veclen && x1 > max_x) {
/* fill some end section of the array with the default or final value */
double frac = (x1 - max_x) / (x1 - x0);
int32_t subveclen = (int32_t) floor (original_veclen * frac);
float val;
subveclen = min (subveclen, veclen);
val = _list.events().back()->value;
i = veclen - subveclen;
for (i = veclen - subveclen; i < veclen; ++i) {
vec[i] = val;
}
veclen -= subveclen;
}
if (veclen == 0) {
return;
}
if (npoints == 1) {
for (i = 0; i < veclen; ++i) {
vec[i] = _list.events().front()->value;
}
return;
}
if (npoints == 2) {
/* linear interpolation between 2 points */
/* XXX I'm not sure that this is the right thing to
do here. but its not a common case for the envisaged
uses.
*/
if (veclen > 1) {
dx = (hx - lx) / (veclen - 1) ;
} else {
dx = 0; // not used
}
double slope = (_list.events().back()->value - _list.events().front()->value)/
(_list.events().back()->when - _list.events().front()->when);
double yfrac = dx*slope;
vec[0] = _list.events().front()->value + slope * (lx - _list.events().front()->when);
for (i = 1; i < veclen; ++i) {
vec[i] = vec[i-1] + yfrac;
}
return;
}
if (_dirty) {
solve ();
}
rx = lx;
if (veclen > 1) {
dx = (hx - lx) / (veclen - 1);
} else {
dx = 0;
}
for (i = 0; i < veclen; ++i, rx += dx) {
vec[i] = multipoint_eval (rx);
}
}
