235 lines
7.8 KiB
C
235 lines
7.8 KiB
C
// Iterative solver for kinematic moves
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//
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// Copyright (C) 2018-2019 Kevin O'Connor <kevin@koconnor.net>
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//
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// This file may be distributed under the terms of the GNU GPLv3 license.
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#include <math.h> // fabs
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#include <stddef.h> // offsetof
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#include <string.h> // memset
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#include "compiler.h" // __visible
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#include "itersolve.h" // itersolve_generate_steps
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#include "pyhelper.h" // errorf
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#include "stepcompress.h" // queue_append_start
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#include "trapq.h" // struct move
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struct timepos {
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double time, position;
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};
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// Find step using "false position" method
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static struct timepos
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itersolve_find_step(struct stepper_kinematics *sk, struct move *m
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, struct timepos low, struct timepos high
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, double target)
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{
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sk_calc_callback calc_position_cb = sk->calc_position_cb;
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struct timepos best_guess = high;
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low.position -= target;
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high.position -= target;
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if (!high.position)
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// The high range was a perfect guess for the next step
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return best_guess;
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int high_sign = signbit(high.position);
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if (high_sign == signbit(low.position))
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// The target is not in the low/high range - return low range
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return (struct timepos){ low.time, target };
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for (;;) {
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double guess_time = ((low.time*high.position - high.time*low.position)
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/ (high.position - low.position));
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if (fabs(guess_time - best_guess.time) <= .000000001)
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break;
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best_guess.time = guess_time;
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best_guess.position = calc_position_cb(sk, m, guess_time);
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double guess_position = best_guess.position - target;
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int guess_sign = signbit(guess_position);
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if (guess_sign == high_sign) {
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high.time = guess_time;
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high.position = guess_position;
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} else {
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low.time = guess_time;
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low.position = guess_position;
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}
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}
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return best_guess;
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}
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// Generate step times for a portion of a move
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static int32_t
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itersolve_gen_steps_range(struct stepper_kinematics *sk, struct move *m
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, double move_start, double move_end)
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{
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struct stepcompress *sc = sk->sc;
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sk_calc_callback calc_position_cb = sk->calc_position_cb;
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double half_step = .5 * sk->step_dist;
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double mcu_freq = stepcompress_get_mcu_freq(sc);
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double start = move_start - m->print_time, end = move_end - m->print_time;
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struct timepos last = { start, sk->commanded_pos }, low = last, high = last;
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double seek_time_delta = 0.000100;
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int sdir = stepcompress_get_step_dir(sc);
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struct queue_append qa = queue_append_start(sc, m->print_time, .5);
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for (;;) {
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// Determine if next step is in forward or reverse direction
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double dist = high.position - last.position;
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if (fabs(dist) < half_step) {
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seek_new_high_range:
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if (high.time >= end)
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// At end of move
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break;
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// Need to increase next step search range
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low = high;
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high.time = last.time + seek_time_delta;
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seek_time_delta += seek_time_delta;
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if (high.time > end)
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high.time = end;
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high.position = calc_position_cb(sk, m, high.time);
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continue;
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}
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int next_sdir = dist > 0.;
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if (unlikely(next_sdir != sdir)) {
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// Direction change
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if (fabs(dist) < half_step + .000000001)
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// Only change direction if going past midway point
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goto seek_new_high_range;
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if (last.time >= low.time) {
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// Must seek new low range to avoid re-finding previous time
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if (high.time < last.time + .000000001)
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goto seek_new_high_range;
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high.time = (last.time + high.time) * .5;
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high.position = calc_position_cb(sk, m, high.time);
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continue;
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}
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int ret = queue_append_set_next_step_dir(&qa, next_sdir);
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if (ret)
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return ret;
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sdir = next_sdir;
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}
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// Find step
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double target = last.position + (sdir ? half_step : -half_step);
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struct timepos next = itersolve_find_step(sk, m, low, high, target);
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// Add step at given time
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int ret = queue_append(&qa, next.time * mcu_freq);
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if (ret)
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return ret;
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seek_time_delta = next.time - last.time;
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if (seek_time_delta < .000000001)
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seek_time_delta = .000000001;
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last.position = target + (sdir ? half_step : -half_step);
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last.time = next.time;
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low = next;
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if (last.time >= high.time)
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// The high range is no longer valid - recalculate it
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goto seek_new_high_range;
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}
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queue_append_finish(qa);
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sk->commanded_pos = last.position;
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if (sk->post_cb)
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sk->post_cb(sk);
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return 0;
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}
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// Check if a move is likely to cause movement on a stepper
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static inline int
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check_active(struct stepper_kinematics *sk, struct move *m)
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{
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int af = sk->active_flags;
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return ((af & AF_X && m->axes_r.x != 0.)
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|| (af & AF_Y && m->axes_r.y != 0.)
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|| (af & AF_Z && m->axes_r.z != 0.));
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}
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// Generate step times for a range of moves on the trapq
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int32_t __visible
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itersolve_generate_steps(struct stepper_kinematics *sk, double flush_time)
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{
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double last_flush_time = sk->last_flush_time;
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sk->last_flush_time = flush_time;
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if (!sk->tq || list_empty(&sk->tq->moves))
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return 0;
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struct move *m = list_first_entry(&sk->tq->moves, struct move, node);
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for (;;) {
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double move_print_time = m->print_time;
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double move_end_time = move_print_time + m->move_t;
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if (last_flush_time >= move_end_time) {
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if (list_is_last(&m->node, &sk->tq->moves))
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break;
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m = list_next_entry(m, node);
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continue;
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}
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double start = move_print_time, end = move_end_time;
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if (start < last_flush_time)
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start = last_flush_time;
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if (start >= flush_time)
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break;
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if (end > flush_time)
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end = flush_time;
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if (check_active(sk, m)) {
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int32_t ret = itersolve_gen_steps_range(sk, m, start, end);
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if (ret)
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return ret;
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}
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last_flush_time = end;
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}
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return 0;
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}
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// Check if the given stepper is likely to be active in the given time range
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double __visible
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itersolve_check_active(struct stepper_kinematics *sk, double flush_time)
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{
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if (!sk->tq || list_empty(&sk->tq->moves))
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return 0.;
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struct move *m = list_first_entry(&sk->tq->moves, struct move, node);
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while (sk->last_flush_time >= m->print_time + m->move_t) {
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if (list_is_last(&m->node, &sk->tq->moves))
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return 0.;
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m = list_next_entry(m, node);
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}
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while (m->print_time < flush_time) {
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if (check_active(sk, m))
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return m->print_time;
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if (list_is_last(&m->node, &sk->tq->moves))
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return 0.;
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m = list_next_entry(m, node);
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}
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return 0.;
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}
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void __visible
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itersolve_set_trapq(struct stepper_kinematics *sk, struct trapq *tq)
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{
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sk->tq = tq;
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}
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void __visible
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itersolve_set_stepcompress(struct stepper_kinematics *sk
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, struct stepcompress *sc, double step_dist)
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{
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sk->sc = sc;
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sk->step_dist = step_dist;
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}
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double __visible
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itersolve_calc_position_from_coord(struct stepper_kinematics *sk
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, double x, double y, double z)
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{
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struct move m;
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memset(&m, 0, sizeof(m));
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m.start_pos.x = x;
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m.start_pos.y = y;
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m.start_pos.z = z;
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return sk->calc_position_cb(sk, &m, 0.);
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}
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void __visible
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itersolve_set_commanded_pos(struct stepper_kinematics *sk, double pos)
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{
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sk->commanded_pos = pos;
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}
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double __visible
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itersolve_get_commanded_pos(struct stepper_kinematics *sk)
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{
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return sk->commanded_pos;
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}
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