symplex 0.5.0

Exact symbolic mathematics for Rust: calculus, summation, solving, linear algebra, transforms, compile-time dimensional analysis, and Rust/C code generation
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
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208

//! Quality tests for codegen output: constant propagation, subtraction style,
//! decimal fractions, zero elimination, and structural validity.

use symplex::matrix::jacobian;
use symplex::prelude::*;
use symplex::robotics::fk_position;

/// Build a 2-DOF planar robot Jacobian and verify no trivial constant temps.
#[test]
fn codegen_2dof_no_trivial_temps() {
    let ctx = Context::new();
    let theta1 = ctx.symbol("theta1");
    let theta2 = ctx.symbol("theta2");
    let l1 = ctx.symbol("L1");
    let l2 = ctx.symbol("L2");
    let zero = ctx.int(0);

    let dh: [(&Ex, &Ex, &Ex, &Ex); 2] =
        [(&theta1, &zero, &l1, &zero), (&theta2, &zero, &l2, &zero)];

    let (px, py, _pz) = fk_position(&dh);
    let jac = jacobian(&[&px, &py], &[&theta1, &theta2]);
    let code = jac
        .to_rust_fn("jacobian_2dof", &["theta1", "theta2", "L1", "L2"])
        .expect("codegen should succeed for 2-DOF Jacobian");

    // No trivial constant temporaries should appear
    assert!(
        !code.contains("= 1.0_f64;"),
        "should not emit `let tN = 1.0_f64;` binding in:\n{code}"
    );
    assert!(
        !code.contains("0.0_f64.powi"),
        "should not emit `0.0_f64.powi(...)` in:\n{code}"
    );
    assert!(
        !code.contains("= 0.0_f64;"),
        "should not emit `let tN = 0.0_f64;` binding in:\n{code}"
    );
}

/// Build a 3-DOF planar robot Jacobian and verify no trivial constant temps.
#[test]
fn codegen_3dof_no_trivial_temps() {
    let ctx = Context::new();
    let theta1 = ctx.symbol("theta1");
    let theta2 = ctx.symbol("theta2");
    let theta3 = ctx.symbol("theta3");
    let l1 = ctx.rational(3, 10);
    let l2 = ctx.rational(1, 4);
    let l3 = ctx.rational(1, 5);
    let zero = ctx.int(0);

    let dh: [(&Ex, &Ex, &Ex, &Ex); 3] = [
        (&theta1, &zero, &l1, &zero),
        (&theta2, &zero, &l2, &zero),
        (&theta3, &zero, &l3, &zero),
    ];

    let (px, py, _pz) = fk_position(&dh);
    let jac = jacobian(&[&px, &py], &[&theta1, &theta2, &theta3]);
    let code = jac
        .to_rust_fn("jacobian_3dof", &["theta1", "theta2", "theta3"])
        .expect("codegen should succeed for 3-DOF Jacobian");

    assert!(
        !code.contains("= 1.0_f64;"),
        "should not emit `let tN = 1.0_f64;` binding in:\n{code}"
    );
    assert!(
        !code.contains("0.0_f64.powi"),
        "should not emit `0.0_f64.powi(...)` in:\n{code}"
    );
    assert!(
        !code.contains("= 0.0_f64;"),
        "should not emit `let tN = 0.0_f64;` binding in:\n{code}"
    );
}

/// Subtraction style: `x + Neg(y)` should emit `- y`, not `+ (-y)`.
#[test]
fn codegen_subtraction_style() {
    let ctx = Context::new();
    let x = ctx.symbol("x");
    let y = ctx.symbol("y");

    // Build x + (-y) explicitly
    let neg_y = -&y;
    let expr = &x + &neg_y;

    let code = expr
        .to_rust_fn("sub_test", &["x", "y"])
        .expect("codegen should succeed");

    assert!(
        code.contains("- "),
        "expected subtraction operator `- ` in:\n{code}"
    );
    assert!(
        !code.contains("+ (-"),
        "should not contain `+ (-` pattern in:\n{code}"
    );
}

/// Fractions should be emitted as decimals, not as `N_f64 / M_f64`.
#[test]
fn codegen_fraction_as_decimal() {
    let ctx = Context::new();
    let x = ctx.symbol("x");
    let quarter = ctx.rational(1, 4);
    let expr = &quarter * &x;

    let code = expr
        .to_rust_fn("frac_test", &["x"])
        .expect("codegen should succeed");

    assert!(code.contains("0.25"), "expected decimal `0.25` in:\n{code}");
    assert!(
        !code.contains("1_f64 / 4_f64"),
        "should not contain fraction syntax `1_f64 / 4_f64` in:\n{code}"
    );
}

/// Zero elimination: `0 * sin(x)` should produce `0.0_f64` or similar.
#[test]
fn codegen_zero_elimination() {
    let ctx = Context::new();
    let x = ctx.symbol("x");
    let zero = ctx.int(0);
    let expr = &zero * &x.sin();

    let code = expr
        .to_rust_fn("zero_test", &["x"])
        .expect("codegen should succeed");

    // The expression should simplify or constant-fold to something with 0.0
    // and should NOT contain a .sin() call since the product is zero
    assert!(
        code.contains("0.0") || code.contains("0_f64"),
        "expected zero result in:\n{code}"
    );
    // After canonicalization, 0*sin(x) should become just 0 — no sin call
    assert!(
        !code.contains(".sin()"),
        "should not contain sin() call for zero product in:\n{code}"
    );
}

/// 3-DOF Jacobian code should have balanced braces and valid structure.
#[test]
fn codegen_3dof_compiles() {
    let ctx = Context::new();
    let theta1 = ctx.symbol("theta1");
    let theta2 = ctx.symbol("theta2");
    let theta3 = ctx.symbol("theta3");
    let l1 = ctx.rational(3, 10);
    let l2 = ctx.rational(1, 4);
    let l3 = ctx.rational(1, 5);
    let zero = ctx.int(0);

    let dh: [(&Ex, &Ex, &Ex, &Ex); 3] = [
        (&theta1, &zero, &l1, &zero),
        (&theta2, &zero, &l2, &zero),
        (&theta3, &zero, &l3, &zero),
    ];

    let (px, py, _pz) = fk_position(&dh);
    let jac = jacobian(&[&px, &py], &[&theta1, &theta2, &theta3]);
    let code = jac
        .to_rust_fn("robot_jac", &["theta1", "theta2", "theta3"])
        .expect("codegen should succeed for 3-DOF Jacobian");

    // Balanced braces
    let open_braces = code.chars().filter(|&c| c == '{').count();
    let close_braces = code.chars().filter(|&c| c == '}').count();
    assert_eq!(
        open_braces, close_braces,
        "unbalanced braces ({open_braces} open vs {close_braces} close) in:\n{code}"
    );

    // Balanced parentheses
    let open_parens = code.chars().filter(|&c| c == '(').count();
    let close_parens = code.chars().filter(|&c| c == ')').count();
    assert_eq!(
        open_parens, close_parens,
        "unbalanced parens ({open_parens} open vs {close_parens} close) in:\n{code}"
    );

    // Balanced brackets
    let open_brackets = code.chars().filter(|&c| c == '[').count();
    let close_brackets = code.chars().filter(|&c| c == ']').count();
    assert_eq!(
        open_brackets, close_brackets,
        "unbalanced brackets ({open_brackets} open vs {close_brackets} close) in:\n{code}"
    );

    // Should contain a valid function signature
    assert!(
        code.contains("pub fn robot_jac("),
        "missing function signature in:\n{code}"
    );

    // Should contain a return type with array
    assert!(
        code.contains("[f64;"),
        "missing array return type in:\n{code}"
    );
}