Class
NumCosmoMathFunctionSampleSet
Description [src]
final class NumCosmoMath.FunctionSampleSet : GObject.Object
{
/* No available fields */
}Ordered sample set for vector-valued functions $\vec{F}: \mathbb{R} \to \mathbb{R}^n$.
This object stores an ordered set of samples $(x_i, \vec{y}_i)$ where each sample consists of a knot position $x_i$ and a vector value $\vec{y}_i \in \mathbb{R}^n$. Each sample also has an associated “interval_ok” flag that indicates whether the interval between that node and the next node has passed refinement tests.
The primary use case is for iterative refinement algorithms that build splines
from vector-valued functions. The typical workflow is:
1. Add initial samples using ncm_function_sample_set_add() or ncm_function_sample_set_add_func()
2. Convert to NcmSplineVec and test interpolation error using ncm_function_sample_set_refine()
3. Insert new samples where error exceeds tolerance using iterator-based insertion
4. Mark samples as interval_ok when bins pass error tests
5. Repeat until ncm_function_sample_set_all_intervals_ok() returns TRUE
Iterator-Based API
This class provides an efficient iterator-based API for traversing and manipulating samples. Iterators provide O(1) access to sample data once positioned, making sequential operations efficient. Example usage:
// Create iterator and traverse all samples (stack-allocated - no free needed)
NcmFunctionSampleSetIter iter_s;
NcmFunctionSampleSetIter *iter = &iter_s;
ncm_function_sample_set_iter_begin (fss, &iter);
while (ncm_function_sample_set_iter_is_valid (iter))
{
gdouble x = ncm_function_sample_set_iter_get_x (iter);
NcmVector *y = ncm_function_sample_set_iter_get_y (iter);
// Process sample...
ncm_function_sample_set_iter_next (iter);
}
// Iterate over intervals using iter_next_pair (stack-allocated iterators)
NcmFunctionSampleSetIter it_s, next_it_s;
NcmFunctionSampleSetIter *it = &it_s;
NcmFunctionSampleSetIter *next_it = &next_it_s;
ncm_function_sample_set_iter_begin (fss, &it);
ncm_function_sample_set_iter_copy (it, &next_it);
while (ncm_function_sample_set_iter_next_pair (it, next_it))
{
if (ncm_function_sample_set_iter_get_interval_ok (it) < threshold)
{
gdouble x_mid = 0.5 * (ncm_function_sample_set_iter_get_x (it) +
ncm_function_sample_set_iter_get_x (next_it));
NcmFunctionSampleSetIter new_it_s;
NcmFunctionSampleSetIter *new_it = &new_it_s;
ncm_function_sample_set_iter_insert_after_func (fss, it, x_mid, func, NULL, &new_it);
}
ncm_function_sample_set_iter_next (it);
}
Memory Management and Performance
Samples are maintained in ascending x-order using a GList internally, which provides efficient insertion operations during the building phase.
When converting to NcmSplineVec using ncm_function_sample_set_to_spline_vec() or
ncm_function_sample_set_to_spline_vec_old(), the object reuses internal cached
arrays for optimal performance. This means:
- Each call to these functions invalidates the previously returned NcmSplineVec
- If you need to preserve multiple splines, call ncm_spline_vec_dup() before
generating a new one
- This pattern matches ncm_spline_func behavior and is optimal for iterative
refinement workflows
The dimension $n$ of the vector values is fixed at creation time and validated on every insertion.
Constructors
ncm_function_sample_set_new
Creates a new NcmFunctionSampleSet for storing samples of a vector-valued
function with output dimension len.
Functions
ncm_function_sample_set_clear
Decreases the reference count of fss and sets the pointer fss to NULL.
Instance methods
ncm_function_sample_set_adaptive_midpoint
Performs an iterative midpoint-based adaptive refinement similar to the
Python test harness. On each iteration intervals with interval_ok <
min_pass_threshold receive their midpoint inserted (evaluated via f). After
insertion, a refinement pass is performed via ncm_function_sample_set_refine(). The
process stops when all intervals reach min_pass_threshold or when max_iter is reached.
ncm_function_sample_set_add
Adds a new sample point to fss with position x and vector value y. The sample is
inserted in the correct position to maintain ascending x-order. The vector y is
copied and must have dimension matching the fss:len property. The interval_ok flag
for the new sample is initialized to 0. The sample is marked as a new point.
ncm_function_sample_set_add_func
Evaluates the vector-valued function f at x and adds the result as a new sample
point. The sample is inserted in the correct position to maintain ascending x-order.
The interval_ok flag for the new sample is initialized to 0. The sample is marked as
a new point.
ncm_function_sample_set_add_old
Adds a new sample point to fss with position x and vector value y, marked as OLD.
This function is useful for boundary extensions where the added point should be
considered part of the base spline rather than a refinement target. The sample is
inserted in the correct position to maintain ascending x-order. The vector y is
copied and must have dimension matching the fss:len property. The interval_ok flag
for the new sample is initialized to 0. The sample is marked as an old point
(new_point = FALSE).
ncm_function_sample_set_add_old_func
Evaluates the vector-valued function f at x and adds the result as an old sample
point. This function is useful for boundary extensions where the added point should
be considered part of the base spline rather than a refinement target. The sample is
inserted in the correct position to maintain ascending x-order. The interval_ok flag
for the new sample is initialized to 0. The sample is marked as an old point
(new_point = FALSE).
ncm_function_sample_set_all_intervals_ok
Checks if all intervals have interval_ok >= threshold. This is useful for
determining convergence in refinement algorithms - when all intervals have passed
the refinement test enough times.
ncm_function_sample_set_expand_domain
Expands the domain of the function sample set by alternating between left and right boundary expansion until convergence or limits are reached. At each step:.
ncm_function_sample_set_free
Decreases the reference count of fss. If the reference count reaches zero,
fss is freed.
ncm_function_sample_set_get_absmaxF
Gets the maximum absolute value observed for component i across all samples. This
is useful for determining appropriate tolerances in refinement algorithms.
ncm_function_sample_set_get_absmaxF_l2_norm
Computes the $L_2$ norm (Euclidean norm) of the maximum absolute values across all components: $$|\vec{F}|2 = \sqrt{\sum{i=0}^{n-1} (\max_x |F_i(x)|)^2}$$.
ncm_function_sample_set_get_absmaxF_linf_norm
Computes the $L_\infty$ norm (maximum norm) of the maximum absolute values across all components: $$|\vec{F}|\infty = \max{i=0}^{n-1} (\max_x |F_i(x)|)$$.
ncm_function_sample_set_get_absmaxF_min
Computes the minimum of the maximum absolute values across all components: $$\min_{i=0}^{n-1} (\max_x |F_i(x)|)$$.
ncm_function_sample_set_iter_begin
Positions an iterator at the first sample in fss.
If fss is empty, the iterator will be invalid.
When iter_out points to a NULL pointer the callee allocates a new iterator
that must be freed with ncm_function_sample_set_iter_free().
When iter_out points to an already-allocated iterator (e.g. a stack variable)
no allocation occurs and no free is required.
ncm_function_sample_set_iter_end
Positions an iterator at the last sample in fss.
If fss is empty, the iterator will be invalid.
When iter_out points to a NULL pointer the callee allocates a new iterator
that must be freed with ncm_function_sample_set_iter_free().
When iter_out points to an already-allocated iterator (e.g. a stack variable)
no allocation occurs and no free is required.
ncm_function_sample_set_iter_insert_after
Inserts a new sample after the position of iter. The vector y must have dimension
matching fss:len property. The new sample’s interval_ok is initialized to 0 and
new_point is set to TRUE. When iter_out points to a NULL pointer the callee
allocates a new iterator that must be freed with
ncm_function_sample_set_iter_free(). When iter_out points to an already-allocated
iterator (e.g. a stack variable) no allocation occurs and no free is required.
ncm_function_sample_set_iter_insert_after_func
Evaluates f at x and inserts the result as a new sample after iter. The new
sample’s interval_ok is initialized to 0 and new_point is set to TRUE. When
iter_out points to a NULL pointer the callee allocates a new iterator that must be
freed with ncm_function_sample_set_iter_free(). When iter_out points to an
already-allocated iterator (e.g. a stack variable) no allocation occurs and no free
is required.
ncm_function_sample_set_iter_insert_before
Inserts a new sample before the position of iter. The vector y must have dimension
matching fss:len property. The new sample’s interval_ok is initialized to 0 and
new_point is set to TRUE. When iter_out points to a NULL pointer the callee
allocates a new iterator that must be freed with
ncm_function_sample_set_iter_free(). When iter_out points to an already-allocated
iterator (e.g. a stack variable) no allocation occurs and no free is required.
ncm_function_sample_set_iter_insert_before_func
Evaluates f at x and inserts the result as a new sample before iter. The new
sample’s interval_ok is initialized to 0 and new_point is set to TRUE. When
iter_out points to a NULL pointer the callee allocates a new iterator that must be
freed with ncm_function_sample_set_iter_free(). When iter_out points to an
already-allocated iterator (e.g. a stack variable) no allocation occurs and no free
is required.
ncm_function_sample_set_log_vals
Logs all sample values in fss for debugging purposes. This prints the x position,
vector components, interval_ok flag, and new_point flag for each sample.
ncm_function_sample_set_mark_all_old
Marks all points in fss as old. This is typically called after a refinement pass to
indicate that all current points should be used in the next spline construction.
ncm_function_sample_set_refine
Performs a refinement pass on all NEW points. For each NEW point, this function: 1. Creates a spline using OLD points only 2. Evaluates the spline at the NEW point position 3. Computes the error: ||f(x) - spline_f(x)||_2 < reltol * ||f(x)||_2 + abstol 4. If the test passes, increments interval_ok for both the NEW point and its left neighbor 5. Marks all NEW points as OLD.
ncm_function_sample_set_reset_interval_ok
Resets all interval_ok flags to 0. This is useful when starting a new refinement pass.
ncm_function_sample_set_to_spline_vec
Converts the sample set to a NcmSplineVec. This reuses cached internal arrays for
efficiency, which means that:.
ncm_function_sample_set_to_spline_vec_old
Converts only the OLD sample points to a NcmSplineVec. This reuses cached internal
arrays for efficiency, which means that:.
Signals
Signals inherited from GObject (1)
GObject::notify
The notify signal is emitted on an object when one of its properties has its value set through g_object_set_property(), g_object_set(), et al.