Modified jerk planner to use no_std and custom sqrt and cbrt routines. These routines do not seem to work yet

firmware/motion-tester/Cargo.toml

@@ -7,4 +7,6 @@ edition = "2021"
 
 [dependencies]
 jerk_control = { path = "../jerk_control" }
-structopt = { version = "0.3.26" }
+# structopt = { version = "0.3.26" }
+
+rayon = "1.5.2"

firmware/motion-tester/src/bin/math_test.rs

@@ -0,0 +1,47 @@
+use rayon::prelude::*;
+
+fn ulp(f: f32) -> f32 {
+    f32::from_bits((f.to_bits() & 0x7f80_0000) - 0x0b80_0000)
+}
+
+fn fn_err(actual: f32, calc: f32) -> f32 {
+    (calc - actual).abs() / actual
+}
+
+
+fn test_all(fname: &str, actual: fn(f32) -> f32, calc: fn(f32) -> f32) {
+    let mut max_err = 0f32;
+    let mut max_err_value = 0f32;
+    (0x01..=0xfe).into_par_iter()
+        .map(|exp| {
+            (0x0..=0x7f_ffff).map(|mant| f32::from_bits((exp << 23) + mant))
+                .max_by_key(|value| fn_err(actual(*value), calc(*value)).to_bits())
+                .unwrap()
+        })
+        .map(|value| (value,fn_err(actual(value), calc(value))))
+        .collect::<Vec<_>>();
+
+    for i in (0x0400_0000..0x0f7f_ffffu32).map(f32::from_bits) {
+        // range of normalized floats...
+        let err = fn_err(actual(i), calc(i));
+        if err > max_err {
+            max_err = err;
+            max_err_value = i;
+        }
+    }
+
+    let max_err_pct = max_err * 100f32;
+    println!("{}: {}% @ {}", fname, max_err_pct, max_err_value);
+    println!(
+        "Value:      0x{:08x}\n
+        Calculated: 0x{:08x}\n
+        Actual:     0x{:08x}",
+        max_err_value.to_bits(),
+        calc(max_err_value).to_bits(), actual(max_err_value).to_bits())
+}
+
+
+fn main() {
+    // test_all("sqrt", f32::sqrt, jerk_control::math_ext::Roots::sqrt);
+    test_all("cbrt", f32::cbrt, jerk_control::math_ext::Roots::cbrt);
+}