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use rhai::plugin::*;
#[export_module]
pub mod int_and_diff {
use crate::if_list_convert_to_vec_float_and_do;
use rhai::{Array, Dynamic, EvalAltResult, Position, FLOAT};
/// Returns the approximate integral of the curve defined by `y` and `x` using the trapezoidal method.
/// ```typescript
/// let y = [1.0, 1.5, 2.0];
/// let x = [1.0, 2.0, 3.0];
/// let A = trapz(x, y);
/// assert_eq(A, 3.0);
/// ```
/// ```typescript
/// let y = [1, 2, 3];
/// let x = [1, 2, 3];
/// let A = trapz(x, y);
/// assert_eq(A, 4.0);
/// ```
#[rhai_fn(name = "trapz", return_raw)]
pub fn trapz(x: Array, y: Array) -> Result<Dynamic, Box<EvalAltResult>> {
if x.len() != y.len() {
Err(EvalAltResult::ErrorArithmetic(
"The arrays must have the same length".to_string(),
Position::NONE,
)
.into())
} else {
if_list_convert_to_vec_float_and_do(&mut y.clone(), |yf| {
if_list_convert_to_vec_float_and_do(&mut x.clone(), |xf| {
let mut trapsum = 0.0;
for i in 1..x.len() {
trapsum += (yf[i] + yf[i - 1]) * (xf[i] - xf[i - 1]) / 2.0;
}
Ok(Dynamic::from_float(trapsum))
})
})
}
}
/// Returns the approximate integral of the curve defined by `y` using the trapezoidal method.
/// Assumes that x-values have unit spacing.
/// ```typescript
/// let y = [1.0, 1.5, 2.0];
/// let A = trapz(y);
/// assert_eq(A, 3.0);
/// ```
/// ```typescript
/// let y = [1, 2, 3];
/// let A = trapz(y);
/// assert_eq(A, 4.0);
/// ```
#[rhai_fn(name = "trapz", return_raw, pure)]
pub fn trapz_unit(arr: &mut Array) -> Result<Dynamic, Box<EvalAltResult>> {
if_list_convert_to_vec_float_and_do(arr, |y| {
let mut trapsum = 0.0 as FLOAT;
for i in 1..y.len() {
trapsum += (y[i] + y[i - 1]) / 2.0;
}
Ok(Dynamic::from_float(trapsum))
})
}
/// Returns the difference between successive elements of a 1-D array.
/// ```typescript
/// let arr = [2, 5, 1, 7, 8];
/// let d = diff(arr);
/// assert_eq(d, [3, -4, 6, 1]);
/// ```
#[rhai_fn(name = "diff", return_raw, pure)]
pub fn diff(arr: &mut Array) -> Result<Array, Box<EvalAltResult>> {
crate::if_list_do_int_or_do_float(
arr,
|arr| {
let mut new_arr = vec![];
for idx in 1..arr.len() {
new_arr.push(Dynamic::from_int(
arr[idx].as_int().unwrap() - arr[idx - 1].as_int().unwrap(),
));
}
Ok(new_arr)
},
|arr| {
let mut new_arr = vec![];
for idx in 1..arr.len() {
new_arr.push(Dynamic::from_float(
arr[idx].as_float().unwrap() - arr[idx - 1].as_float().unwrap(),
));
}
Ok(new_arr)
},
)
}
}