factrs 0.3.0

Factor graph optimization for robotics
Documentation 
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
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174

use std::{fmt, ops};

use super::Variable;
use crate::{
    dtype,
    linalg::{Const, DualVector, Numeric, SupersetOf, Vector3, VectorDim},
    residuals::{Accel, Gyro},
};

// TODO: Use newtypes internally as well?
/// IMU bias
///
/// The IMU bias is a 6D vector containing the gyro and accel biases. It is
/// treated as a 6D vector for optimization purposes.
#[derive(Clone)]
#[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
pub struct ImuBias<T: Numeric = dtype> {
    gyro: Vector3<T>,
    accel: Vector3<T>,
}

impl<T: Numeric> ImuBias<T> {
    /// Create a new IMU bias
    pub fn new(gyro: Gyro<T>, accel: Accel<T>) -> Self {
        ImuBias {
            gyro: gyro.0,
            accel: accel.0,
        }
    }

    /// Create an IMU bias of zeros (same as identity)
    pub fn zeros() -> Self {
        ImuBias {
            gyro: Vector3::zeros(),
            accel: Vector3::zeros(),
        }
    }

    /// Get the gyro bias
    pub fn gyro(&self) -> &Vector3<T> {
        &self.gyro
    }

    /// Get the accel bias
    pub fn accel(&self) -> &Vector3<T> {
        &self.accel
    }
}

#[factrs::mark]
impl<T: Numeric> Variable for ImuBias<T> {
    type T = T;
    type Dim = crate::linalg::Const<6>;
    type Alias<TT: Numeric> = ImuBias<TT>;

    fn identity() -> Self {
        ImuBias {
            gyro: Vector3::zeros(),
            accel: Vector3::zeros(),
        }
    }

    fn inverse(&self) -> Self {
        ImuBias {
            gyro: -self.gyro,
            accel: -self.accel,
        }
    }

    fn compose(&self, other: &Self) -> Self {
        ImuBias {
            gyro: self.gyro + other.gyro,
            accel: self.accel + other.accel,
        }
    }

    fn exp(delta: crate::linalg::VectorViewX<T>) -> Self {
        let gyro = Vector3::new(delta[0], delta[1], delta[2]);
        let accel = Vector3::new(delta[3], delta[4], delta[5]);
        ImuBias { gyro, accel }
    }

    fn log(&self) -> crate::linalg::VectorX<T> {
        crate::linalg::vectorx![
            self.gyro.x,
            self.gyro.y,
            self.gyro.z,
            self.accel.x,
            self.accel.y,
            self.accel.z
        ]
    }

    fn cast<TT: Numeric + SupersetOf<Self::T>>(&self) -> Self::Alias<TT> {
        ImuBias {
            gyro: self.gyro.cast(),
            accel: self.accel.cast(),
        }
    }

    fn dual_exp<N: nalgebra::DimName>(idx: usize) -> Self::Alias<crate::linalg::DualVector<N>>
    where
        crate::linalg::AllocatorBuffer<N>: Sync + Send,
        nalgebra::DefaultAllocator: crate::linalg::DualAllocator<N>,
        crate::linalg::DualVector<N>: Copy,
    {
        let n = VectorDim::<N>::zeros().shape_generic().0;

        let mut gyro = Vector3::<DualVector<N>>::zeros();
        for (i, gi) in gyro.iter_mut().enumerate() {
            gi.eps = num_dual::Derivative::derivative_generic(n, Const::<1>, idx + i);
        }

        let mut accel = Vector3::<DualVector<N>>::zeros();
        for (i, ai) in accel.iter_mut().enumerate() {
            ai.eps = num_dual::Derivative::derivative_generic(n, Const::<1>, idx + i + 3);
        }

        ImuBias { gyro, accel }
    }
}

impl<T: Numeric> fmt::Display for ImuBias<T> {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        let precision = f.precision().unwrap_or(3);
        write!(
            f,
            "ImuBias(g: ({:.p$}, {:.p$}, {:.p$}), a: ({:.p$}, {:.p$}, {:.p$}))",
            self.gyro.x,
            self.gyro.y,
            self.gyro.z,
            self.accel.x,
            self.accel.y,
            self.accel.z,
            p = precision
        )
    }
}

impl<T: Numeric> fmt::Debug for ImuBias<T> {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        fmt::Display::fmt(self, f)
    }
}

impl<T: Numeric> ops::Sub for ImuBias<T> {
    type Output = Self;

    fn sub(self, rhs: Self) -> Self {
        ImuBias {
            gyro: self.gyro - rhs.gyro,
            accel: self.accel - rhs.accel,
        }
    }
}

impl<T: Numeric> ops::Sub for &ImuBias<T> {
    type Output = ImuBias<T>;

    fn sub(self, rhs: Self) -> ImuBias<T> {
        ImuBias {
            gyro: self.gyro - rhs.gyro,
            accel: self.accel - rhs.accel,
        }
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use crate::test_variable;

    test_variable!(ImuBias);
}