math-interpolate

Install

``
$ yarn add math-interpolate
`

Interpolation cases usage

_So, you can use methods below_

- linear by ({ x, x1, y1, x2, y2 })
- bilinear by ({ x, y, x1, y1, x2, y2, q11, q12, q21, q22 })
- byInternalTable by ({ x, y, tableAsDoubleArray } _TODO: external cases_
- getKB for condition like y = (k * x) + b by { x1, y1, x2, y2 }
- getCommonPointByBisectionMethod by ({ fn1, fn2, xMin = -1000, xMax = 1000, eps = 0.001 })

$3

`js
import { linear } from 'math-interpolate'

console.log(linear({ x: 0.5, x1: 0, y1: 1, x2: 1, y2: 2 }))
// 1.5
`

_This example description_

`
|
y2= 2 | o
|
y= ? | o
(1.5 will be found)
y1= 1 o
|
------------------------------------
x1= 0 x= 0.5 x2= 1
`

$3

`js
import { bilinear } from 'math-interpolate'

console.log(
bilinear({
x1: 1,
q11: 400,
q12: 410,
y1: 1,
x2: 6,
q21: 210,
q22: 590,
y2: 5,
x: 3,
y: 3.5,
}),
)
// 377.75
`

_This example description_

`
| q12= 410 q22= 590
y2= 5 | o o
|
| q= ? (377.75 will be found)
y= 3.5 | o
|
| q11= 400 q21= 210
y1= 1 | o o
------------------------------------
x1= 1 x= 3 x2= 6
`

And also, you can read more about bilinear interpolation on wiki.

$3

_Interpolate by table (only internal table values gives correct result) for example_

`js
import { byInternalTable } from 'math-interpolate'

const temperature = -21.0
const percentage = 20.0
/*
About table below:
1st horizontal line (highest row as x axis) - temperature conditions template
1st vertical column (first left column as y axis) - percentage conditions template
*/
const tableAsDoubleArray = [
[0.0, -30, -20.0, -10.0, 0.0, 20.0, 40.0, 60.0, 80.0, 100.0],
[0.0, 4.19, 4.19, 4.19, 4.19, 4.19, 4.19, 4.19, 4.19, 4.19],
[25.0, 3.93, 3.93, 3.93, 3.95, 3.98, 4.0, 4.03, 4.05, 4.08],
[37.0, 3.68, 3.68, 3.7, 3.72, 3.77, 3.82, 3.88, 3.94, 4.0],
[45.0, 3.49, 3.49, 3.52, 3.56, 3.62, 3.69, 3.76, 3.82, 3.89],
]

console.log(
byInternalTable({
x: temperature,
y: percentage,
tableAsDoubleArray,
}),
)
// 3.982
`

$3

`js
import { getKB } from 'math-interpolate'

console.log(
getKB({
x1: 1,
y1: 1,
x2: 6,
y2: 5,
}),
)
// { k: -0.8,
// b: 1.8 }
`

$3

`js
import { getCommonPointByBisectionMethod } from 'math-interpolate'

console.log(
getCommonPointByBisectionMethod({
fn1: (x) => x,
fn2: (x) => -x,
xMin: -200, // -1000 by default
xMax: 200, // 1000 by default
eps: 0.001, // 0.001 by default (accuracy)
iMax: 1000, // 1000 by default (max iterations number)
}),
)
// { error: false,
// x: ~0,
// y: ~0 }
`

_This example description_

`
|
y2= 2 o o
|
y= ? | o
(~1.5 will be found)
y1= 1 o o
|
------------------------------------
x1= 0 x= ? x2= 1
(~0.5 will be found)
`

`js
import { getKB, getCommonPointByBisectionMethod } from 'math-interpolate'

const { k: k1, b: b1 } = getKB({ x1: 0, y1: 1, x2: 1, y2: 2 })
const { k: k2, b: b2 } = getKB({ x1: 0, y1: 2, x2: 1, y2: 1 })
const fn1 = (x) => k1 * x + b1
const fn2 = (x) => k2 * x + b2

console.log(
getCommonPointByBisectionMethod({
fn1,
fn2,
}),
)
// { error: false, // & description field if true
// x: 0.5002021789550781,
// y: 1.5002021789550781 }
`

Commands

- npm run clean - Remove lib/ directory
- npm test - Run tests with linting and coverage results.
- npm test:only - Run tests without linting or coverage.
- npm test:watch - You can even re-run tests on file changes!
- npm test:prod - Run tests with minified code.
- npm run test:examples - Test written examples on pure JS for better understanding module usage.
- npm run lint - Run ESlint with airbnb-config
- npm run cover - Get coverage report for your code.
- npm run build - Babel will transpile ES6 => ES5 and minify the code.
- npm run prepublish` - Hook for npm. Do all the checks before publishing your module.

License

MIT © Den Pol