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add support for derivatives

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This commit is contained in:
Simon Gardling
2022-03-04 09:19:04 -05:00
parent 7efd523436
commit 3e6e0e5adb
2 changed files with 84 additions and 12 deletions
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64
src/function.rs
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@@ -30,8 +30,10 @@ pub struct Function {
back_cache: Option<Vec<Value>>,
front_cache: Option<(Vec<Bar>, f64)>,
derivative_cache: Option<Vec<Value>>,
pub(crate) integral: bool,
pub(crate) derivative: bool,
integral_min_x: f64,
integral_max_x: f64,
integral_num: usize,
@@ -41,6 +43,8 @@ pub struct Function {
// x^2 function, set here so we don't have to regenerate it every time a new function is made
fn default_function(x: f64) -> f64 { x.powi(2) }
const EPSILON: f64 = 5.0e-7;
impl Function {
// Creates Empty Function instance
pub fn empty() -> Self {
@@ -52,7 +56,9 @@ impl Function {
pixel_width: 100,
back_cache: None,
front_cache: None,
derivative_cache: None,
integral: false,
derivative: false,
integral_min_x: f64::NAN,
integral_max_x: f64::NAN,
integral_num: 0,
@@ -64,7 +70,7 @@ impl Function {
fn run_func(&self, x: f64) -> f64 { (self.function)(x) }
pub fn update(
&mut self, func_str: String, integral: bool, integral_min_x: Option<f64>,
&mut self, func_str: String, integral: bool, derivative: bool, integral_min_x: Option<f64>,
integral_max_x: Option<f64>, integral_num: Option<usize>, sum: Option<RiemannSum>,
) {
// If the function string changes, just wipe and restart from scratch
@@ -76,8 +82,10 @@ impl Function {
});
self.back_cache = None;
self.front_cache = None;
self.derivative_cache = None;
}
self.derivative = derivative;
self.integral = integral;
// Makes sure proper arguments are passed when integral is enabled
@@ -98,6 +106,7 @@ impl Function {
pub fn update_bounds(&mut self, min_x: f64, max_x: f64, pixel_width: usize) {
if pixel_width != self.pixel_width {
self.back_cache = None;
self.derivative_cache = None;
self.min_x = min_x;
self.max_x = max_x;
self.pixel_width = pixel_width;
@@ -123,15 +132,17 @@ impl Function {
})
.collect(),
);
self.derivative_cache = None; // TODO: setup this caching system for derivatives
} else {
self.back_cache = None;
self.derivative_cache = None;
self.min_x = min_x;
self.max_x = max_x;
self.pixel_width = pixel_width;
}
}
pub fn run_back(&mut self) -> (Vec<Value>, Option<(Vec<Bar>, f64)>) {
pub fn run_back(&mut self) -> (Vec<Value>, Option<(Vec<Bar>, f64)>, Option<Vec<Value>>) {
let back_values: Vec<Value> = {
if self.back_cache.is_none() {
let resolution: f64 =
@@ -147,6 +158,28 @@ impl Function {
self.back_cache.as_ref().unwrap().clone()
};
let derivative_values: Option<Vec<Value>> = match self.derivative {
true => {
if self.derivative_cache.is_none() {
let back_cache = self.back_cache.as_ref().unwrap().clone();
self.derivative_cache = Some(
back_cache
.iter()
.map(|ele| {
let x = ele.x;
let (x1, x2) = (x - EPSILON, x + EPSILON);
let (y1, y2) = (self.run_func(x1), self.run_func(x2));
let slope = (y2 - y1) / (EPSILON * 2.0);
Value::new(x, slope)
})
.collect(),
);
}
Some(self.derivative_cache.as_ref().unwrap().clone())
}
false => None,
};
let front_bars = match self.integral {
true => {
if self.front_cache.is_none() {
@@ -160,11 +193,11 @@ impl Function {
false => None,
};
(back_values, front_bars)
(back_values, front_bars, derivative_values)
}
pub fn run(&mut self) -> (Line, Option<(BarChart, f64)>) {
let (back_values, front_data_option) = self.run_back();
pub fn run(&mut self) -> (Line, Option<(BarChart, f64)>, Option<Line>) {
let (back_values, front_data_option, derivative_option) = self.run_back();
(
Line::new(Values::from_values(back_values)),
@@ -173,6 +206,11 @@ impl Function {
} else {
None
},
if let Some(derivative_data) = derivative_option {
Some(Line::new(Values::from_values(derivative_data)))
} else {
None
},
)
}
@@ -243,7 +281,9 @@ fn left_function_test() {
pixel_width: 10,
back_cache: None,
front_cache: None,
derivative_cache: None,
integral: false,
derivative: false,
integral_min_x: -1.0,
integral_max_x: 1.0,
integral_num: 10,
@@ -251,7 +291,7 @@ fn left_function_test() {
};
{
let (back_values, bars) = function.run_back();
let (back_values, bars, _) = function.run_back();
assert!(bars.is_none());
assert_eq!(back_values.len(), 10);
let back_values_tuple: Vec<(f64, f64)> =
@@ -275,7 +315,7 @@ fn left_function_test() {
{
function = function.integral(true);
let (back_values, bars) = function.run_back();
let (back_values, bars, _) = function.run_back();
assert!(bars.is_some());
assert_eq!(back_values.len(), 10);
assert_eq!(bars.clone().unwrap().1, 0.8720000000000001);
@@ -294,7 +334,9 @@ fn middle_function_test() {
pixel_width: 10,
back_cache: None,
front_cache: None,
derivative_cache: None,
integral: false,
derivative: false,
integral_min_x: -1.0,
integral_max_x: 1.0,
integral_num: 10,
@@ -302,7 +344,7 @@ fn middle_function_test() {
};
{
let (back_values, bars) = function.run_back();
let (back_values, bars, _) = function.run_back();
assert!(bars.is_none());
assert_eq!(back_values.len(), 10);
let back_values_tuple: Vec<(f64, f64)> =
@@ -326,7 +368,7 @@ fn middle_function_test() {
{
function = function.integral(true);
let (back_values, bars) = function.run_back();
let (back_values, bars, _) = function.run_back();
assert!(bars.is_some());
assert_eq!(back_values.len(), 10);
assert_eq!(bars.clone().unwrap().1, 0.9200000000000002);
@@ -345,7 +387,9 @@ fn right_function_test() {
pixel_width: 10,
back_cache: None,
front_cache: None,
derivative_cache: None,
integral: false,
derivative: false,
integral_min_x: -1.0,
integral_max_x: 1.0,
integral_num: 10,
@@ -377,7 +421,7 @@ fn right_function_test() {
{
function = function.integral(true);
let (back_values, bars) = function.run_back();
let (back_values, bars, _) = function.run_back();
assert!(bars.is_some());
assert_eq!(back_values.len(), 10);
assert_eq!(bars.clone().unwrap().1, 0.9680000000000002);