Copp_interpolation

Files
file	bindings/c/include/copp/interpolation.h
	Second- and third-order interpolation utilities.

Functions
enum CoppStatus	copp_a_to_b_2nd (struct CoppSliceF64 s, struct CoppSliceF64 a, struct CoppVecF64 *out_b)
	Compute TOPP2 segment profile b from node profile a.
enum CoppStatus	copp_s_to_t_2nd (struct CoppSliceF64 s, struct CoppSliceF64 a, double t0, double *out_t_final, struct CoppVecF64 *out_t_s)
	Compute cumulative TOPP2 time profile t(s) from node profile a(s).
enum CoppStatus	copp_t_to_s_uniform_2nd (struct CoppSliceF64 s, struct CoppSliceF64 a, struct CoppSliceF64 t_s, double t0, double dt, bool include_final, struct CoppVecF64 *out_s_t)
	Interpolate s(t) from TOPP2 profiles using a uniform time grid.
enum CoppStatus	copp_t_to_s_non_uniform_2nd (struct CoppSliceF64 s, struct CoppSliceF64 a, struct CoppSliceF64 t_s, struct CoppSliceF64 t_sample, struct CoppVecF64 *out_s_t)
	Interpolate s(t) from TOPP2 profiles using caller-provided time samples.
enum CoppStatus	copp_s_to_t_3rd (struct CoppSliceF64 s, struct CoppSliceF64 a, struct CoppSliceF64 b, size_t num_stationary_start, size_t num_stationary_end, double t0, double *out_t_final, struct CoppVecF64 *out_t_s)
	Compute cumulative TOPP3/COPP3 time profile t(s) from node profiles a(s) = dot{s}^2 and b(s) = ddot{s}.
enum CoppStatus	copp_t_to_s_uniform_3rd (struct CoppSliceF64 s, struct CoppSliceF64 a, struct CoppSliceF64 b, size_t num_stationary_start, size_t num_stationary_end, struct CoppSliceF64 t_s, double t0, double dt, bool include_final, struct CoppVecF64 *out_s_t)
	Interpolate s(t) from TOPP3/COPP3 profiles using a uniform time grid.
enum CoppStatus	copp_t_to_s_non_uniform_3rd (struct CoppSliceF64 s, struct CoppSliceF64 a, struct CoppSliceF64 b, size_t num_stationary_start, size_t num_stationary_end, struct CoppSliceF64 t_s, struct CoppSliceF64 t_sample, struct CoppVecF64 *out_s_t)
	Interpolate s(t) from TOPP3/COPP3 profiles using caller-provided time samples.
enum CoppStatus	copp_force_positive_a_3rd (struct CoppSliceF64 s, struct CoppSliceMutF64 a, struct CoppSliceMutF64 b, size_t num_stationary_start, size_t num_stationary_end, double a_min, bool *out_succeed)
	Adjust mutable TOPP3/COPP3 a and b node profiles in place so interpolated a(s) stays strictly positive per interval.

Detailed Description

Function Documentation

copp_a_to_b_2nd()

enum CoppStatus copp_a_to_b_2nd	(	struct CoppSliceF64	s,
		struct CoppSliceF64	a,
		struct CoppVecF64 *	out_b )

Compute TOPP2 segment profile b from node profile a.

On success, out_b owns a COPP-allocated vector and must be released with copp_vec_f64_free.

Example

The example below converts a solved second-order node profile into interval-based b values.

struct CoppVecF64 b = {0};
check(copp_a_to_b_2nd(
    (struct CoppSliceF64){s, n},
    (struct CoppSliceF64){a.data, a.len},
    &b));
copp_vec_f64_free(b);

Safety

s.data and a.data must be valid for len reads when their lengths are non-zero. out_b must be valid for one CoppVecF64 write.

copp_s_to_t_2nd()

enum CoppStatus copp_s_to_t_2nd	(	struct CoppSliceF64	s,
		struct CoppSliceF64	a,
		double	t0,
		double *	out_t_final,
		struct CoppVecF64 *	out_t_s )

Compute cumulative TOPP2 time profile t(s) from node profile a(s).

On success, *out_t_final receives the final time and out_t_s owns a COPP-allocated vector that must be released with copp_vec_f64_free.

Example

The example below converts a TOPP2 a(s) profile into cumulative time samples and the final duration.

double t_final = 0.0;
struct CoppVecF64 t_s = {0};
check(copp_s_to_t_2nd(
    (struct CoppSliceF64){s, n},
    (struct CoppSliceF64){a.data, a.len},
    0.0,
    &t_final,
    &t_s));
copp_vec_f64_free(t_s);

Safety

s.data and a.data must be valid for len reads when their lengths are non-zero. out_t_final must be valid for one double write and out_t_s must be valid for one CoppVecF64 write. C callers can pass the address of ordinary stack variables; heap allocation is not required for these outputs.

copp_t_to_s_uniform_2nd()

enum CoppStatus copp_t_to_s_uniform_2nd	(	struct CoppSliceF64	s,
		struct CoppSliceF64	a,
		struct CoppSliceF64	t_s,
		double	t0,
		double	dt,
		bool	include_final,
		struct CoppVecF64 *	out_s_t )

Interpolate s(t) from TOPP2 profiles using a uniform time grid.

On success, out_s_t owns a COPP-allocated vector and must be released with copp_vec_f64_free.

Example

The example below resamples a TOPP2 trajectory on a uniform time grid.

struct CoppVecF64 s_t = {0};
check(copp_t_to_s_uniform_2nd(
    (struct CoppSliceF64){s, n},
    (struct CoppSliceF64){a.data, a.len},
    (struct CoppSliceF64){t_s.data, t_s.len},
    0.0,
    1e-3,
    true,
    &s_t));
copp_vec_f64_free(s_t);

Safety

s.data, a.data, and t_s.data must be valid for len reads when their lengths are non-zero. out_s_t must be valid for one CoppVecF64 write.

copp_t_to_s_non_uniform_2nd()

enum CoppStatus copp_t_to_s_non_uniform_2nd	(	struct CoppSliceF64	s,
		struct CoppSliceF64	a,
		struct CoppSliceF64	t_s,
		struct CoppSliceF64	t_sample,
		struct CoppVecF64 *	out_s_t )

Interpolate s(t) from TOPP2 profiles using caller-provided time samples.

On success, out_s_t owns a COPP-allocated vector and must be released with copp_vec_f64_free.

Safety

s.data, a.data, t_s.data, and t_sample.data must be valid for len reads when their lengths are non-zero. out_s_t must be valid for one CoppVecF64 write.

copp_s_to_t_3rd()

enum CoppStatus copp_s_to_t_3rd	(	struct CoppSliceF64	s,
		struct CoppSliceF64	a,
		struct CoppSliceF64	b,
		size_t	num_stationary_start,
		size_t	num_stationary_end,
		double	t0,
		double *	out_t_final,
		struct CoppVecF64 *	out_t_s )

Compute cumulative TOPP3/COPP3 time profile t(s) from node profiles a(s) = dot{s}^2 and b(s) = ddot{s}.

C callers pass profile parts explicitly: a and b are node-based arrays with length s.len, and num_stationary_* are the effective stationary interval counts at the start and end.

On success, *out_t_final receives the final time and out_t_s owns a COPP-allocated vector that must be released with copp_vec_f64_free.

Example

The example below converts a TOPP3/COPP3 profile into cumulative time samples and the final duration.

double t_final = 0.0;
struct CoppVecF64 t_s = {0};
check(copp_s_to_t_3rd(
    (struct CoppSliceF64){s, n},
    (struct CoppSliceF64){profile.a.data, profile.a.len},
    (struct CoppSliceF64){profile.b.data, profile.b.len},
    profile.num_stationary_start,
    profile.num_stationary_end,
    0.0,
    &t_final,
    &t_s));
copp_vec_f64_free(t_s);

Safety

s.data, a.data, and b.data must be valid for reads when their lengths are non-zero. out_t_final must be valid for one double write and out_t_s must be valid for one CoppVecF64 write.

copp_t_to_s_uniform_3rd()

enum CoppStatus copp_t_to_s_uniform_3rd	(	struct CoppSliceF64	s,
		struct CoppSliceF64	a,
		struct CoppSliceF64	b,
		size_t	num_stationary_start,
		size_t	num_stationary_end,
		struct CoppSliceF64	t_s,
		double	t0,
		double	dt,
		bool	include_final,
		struct CoppVecF64 *	out_s_t )

Interpolate s(t) from TOPP3/COPP3 profiles using a uniform time grid.

C callers pass profile parts explicitly. On success, out_s_t owns a COPP-allocated vector and must be released with copp_vec_f64_free.

Example

The example below resamples a third-order profile on a uniform time grid.

struct CoppVecF64 s_t = {0};
check(copp_t_to_s_uniform_3rd(
    (struct CoppSliceF64){s, n},
    (struct CoppSliceF64){profile.a.data, profile.a.len},
    (struct CoppSliceF64){profile.b.data, profile.b.len},
    profile.num_stationary_start,
    profile.num_stationary_end,
    (struct CoppSliceF64){t_s.data, t_s.len},
    0.0,
    1e-3,
    true,
    &s_t));
copp_vec_f64_free(s_t);

Safety

s.data, a.data, b.data, and t_s.data must be valid for reads when their lengths are non-zero. out_s_t must be valid for one CoppVecF64 write.

copp_t_to_s_non_uniform_3rd()

enum CoppStatus copp_t_to_s_non_uniform_3rd	(	struct CoppSliceF64	s,
		struct CoppSliceF64	a,
		struct CoppSliceF64	b,
		size_t	num_stationary_start,
		size_t	num_stationary_end,
		struct CoppSliceF64	t_s,
		struct CoppSliceF64	t_sample,
		struct CoppVecF64 *	out_s_t )

Interpolate s(t) from TOPP3/COPP3 profiles using caller-provided time samples.

C callers pass profile parts explicitly. On success, out_s_t owns a COPP-allocated vector and must be released with copp_vec_f64_free.

Safety

s.data, a.data, b.data, t_s.data, and t_sample.data must be valid for reads when their lengths are non-zero. out_s_t must be valid for one CoppVecF64 write.

copp_force_positive_a_3rd()

enum CoppStatus copp_force_positive_a_3rd	(	struct CoppSliceF64	s,
		struct CoppSliceMutF64	a,
		struct CoppSliceMutF64	b,
		size_t	num_stationary_start,
		size_t	num_stationary_end,
		double	a_min,
		bool *	out_succeed )

Adjust mutable TOPP3/COPP3 a and b node profiles in place so interpolated a(s) stays strictly positive per interval.

C callers pass mutable profile parts explicitly. a and b must be mutable node-based arrays with length s.len. On success, *out_succeed receives the operation result flag; the a.data and b.data buffers may have been modified.

Example

The example below repairs a mutable third-order profile in place before downstream interpolation.

bool succeeded = false;
check(copp_force_positive_a_3rd(
    (struct CoppSliceF64){s, n},
    (struct CoppSliceMutF64){profile.a.data, profile.a.len},
    (struct CoppSliceMutF64){profile.b.data, profile.b.len},
    profile.num_stationary_start,
    profile.num_stationary_end,
    1e-12,
    &succeeded));

Safety

s.data must be valid for reads when non-empty. a.data and b.data must be valid for unique mutable access when non-empty and must not alias each other. out_succeed must be valid for one bool write.