aboutsummaryrefslogtreecommitdiff
path: root/src/dynamics/solver/parallel_velocity_solver.rs
blob: 69ceb03ff7e98f50038db78dd1e4292470595adb (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
use super::{AnyJointVelocityConstraint, AnyVelocityConstraint, DeltaVel, ThreadContext};
use crate::dynamics::solver::generic_velocity_constraint::GenericVelocityConstraint;
use crate::dynamics::solver::ParallelSolverConstraints;
use crate::dynamics::{IntegrationParameters, JointGraphEdge};
use crate::geometry::ContactManifold;
use crate::math::Real;
use na::DVector;
use std::sync::atomic::Ordering;

pub(crate) struct ParallelVelocitySolver {
    pub mj_lambdas: Vec<DeltaVel<Real>>,
    pub generic_mj_lambdas: DVector<Real>,
}

impl ParallelVelocitySolver {
    pub fn new() -> Self {
        Self {
            mj_lambdas: Vec::new(),
            generic_mj_lambdas: DVector::zeros(0),
        }
    }

    pub fn solve(
        &mut self,
        thread: &ThreadContext,
        params: &IntegrationParameters,
        manifolds_all: &mut [&mut ContactManifold],
        joints_all: &mut [JointGraphEdge],
        contact_constraints: &mut ParallelSolverConstraints<
            AnyVelocityConstraint,
            GenericVelocityConstraint,
        >,
        joint_constraints: &mut ParallelSolverConstraints<AnyJointVelocityConstraint, ()>,
    ) {
        if contact_constraints.constraint_descs.is_empty()
            && joint_constraints.constraint_descs.is_empty()
        {
            return;
        }

        /*
         * Solve constraints.
         */
        {
            // Each thread will concurrently grab thread.batch_size constraint desc to
            // solve. If the batch size is large enough for to cross the boundary of
            // a parallel_desc_group, we have to wait util the current group is finished
            // before starting the next one.
            let mut start_index = thread
                .solve_interaction_index
                .fetch_add(thread.batch_size, Ordering::SeqCst);
            let mut batch_size = thread.batch_size;
            let contact_descs = &contact_constraints.constraint_descs[..];
            let joint_descs = &joint_constraints.constraint_descs[..];
            let mut target_num_desc = 0;
            let mut shift = 0;

            for _ in 0..params.max_velocity_iterations {
                macro_rules! solve {
                    ($part: expr, $($solve_args: expr),*) => {
                        // ImpulseJoint groups.
                        for group in $part.parallel_desc_groups.windows(2) {
                            let num_descs_in_group = group[1] - group[0];

                            target_num_desc += num_descs_in_group;

                            while start_index < group[1] {
                                let end_index = (start_index + batch_size).min(group[1]);

                                let constraints = if end_index == $part.constraint_descs.len() {
                                    &mut $part.velocity_constraints
                                        [$part.constraint_descs[start_index].0..]
                                } else {
                                    &mut $part.velocity_constraints[$part.constraint_descs
                                        [start_index]
                                        .0
                                        ..$part.constraint_descs[end_index].0]
                                };

                                for constraint in constraints {
                                    constraint.solve(
                                        $($solve_args),*
                                    );
                                }

                                let num_solved = end_index - start_index;
                                batch_size -= num_solved;

                                thread
                                    .num_solved_interactions
                                    .fetch_add(num_solved, Ordering::SeqCst);

                                if batch_size == 0 {
                                    start_index = thread
                                        .solve_interaction_index
                                        .fetch_add(thread.batch_size, Ordering::SeqCst);
                                    start_index -= shift;
                                    batch_size = thread.batch_size;
                                } else {
                                    start_index += num_solved;
                                }
                            }
                            ThreadContext::lock_until_ge(
                                &thread.num_solved_interactions,
                                target_num_desc,
                            );
                        }
                    };
                }

                solve!(
                    joint_constraints,
                    &joint_constraints.generic_jacobians,
                    &mut self.mj_lambdas,
                    &mut self.generic_mj_lambdas
                );
                shift += joint_descs.len();
                start_index -= joint_descs.len();
                solve!(contact_constraints, &mut self.mj_lambdas, true, true);
                shift += contact_descs.len();
                start_index -= contact_descs.len();
            }
        }

        /*
         * Writeback impulses.
         */
        let joint_constraints = &joint_constraints.velocity_constraints;
        let contact_constraints = &contact_constraints.velocity_constraints;

        crate::concurrent_loop! {
             let batch_size = thread.batch_size;
             for constraint in joint_constraints[thread.joint_writeback_index] {
                 constraint.writeback_impulses(joints_all);
             }
        }
        crate::concurrent_loop! {
             let batch_size = thread.batch_size;
             for constraint in contact_constraints[thread.impulse_writeback_index] {
                 constraint.writeback_impulses(manifolds_all);
             }
        }
    }
}