lsq.js

/*

input previous system measurements as state (lists)
make predictions for y based on input at x, with lsq. from old data
to expand: accept arrays as inputs, from automatic measurements ?

*/

import {
  Hunkify,
  Input,
  Output,
  State
} from '../hunks.js'

import smallmath from '../../libs/smallmath.js'

export default function LeastSquares() {
  Hunkify(this)

  let loadCellInput = new Input('number', 'reading', this)
  this.inputs.push(loadCellInput)

  let loadReading = new Output('number', 'prediction', this)
  this.outputs.push(loadReading)

  let isOkToCalc = false
  // admit unwillingness to write nice array wrappers,
  // do that locally ..
  let xStateArray = new State('string', 'csv: readings: x', '25, 14854, 29649, 44453, 74061, 103695')
  let yStateArray = new State('string', 'csv: readings: y', '0, -0.100, -0.200, -0.300, -0.500, -0.700')
  // state!
  let m, b = 0
  let writeCalExpression = () => {
    let exes = xStateArray.value.split(',')
    let whys = yStateArray.value.split(',')
    // haha, sorry
    for (let x in exes) {
      exes[x] = parseInt(exes[x])
    }
    for (let y in whys) {
      whys[y] = parseFloat(whys[y])
    }
    if (exes.length === whys.length && exes.length > 2) {
      // we gucc 2 lsq
      let lsqr = smallmath.lsq(exes, whys)
      m = lsqr.m
      b = lsqr.b
      isOkToCalc = true
      console.log(`m, ${m}, b, ${b}`)
      // we round 'em out a bit ... local values are full width;
      if (b >= 0) {
        return `${m.toExponential(2)} x + ${b.toExponential(2)}`
      } else {
        return `${m.toExponential(2)} x ${b.toExponential(2)}`
      }
    } else {
      isOkToCalc = false
      return 'bad inputs ...'
    }
  }
  let result = new State('string', 'calibration result', writeCalExpression())
  this.states.push(xStateArray, yStateArray, result)
  xStateArray.onChange = (value) => {
    xStateArray.set(value)
    result.set(writeCalExpression())
  }
  yStateArray.onChange = (value) => {
    yStateArray.set(value)
    result.set(writeCalExpression())
  }

  this.init = () => {
    result.set(writeCalExpression())
  }

  this.loop = () => {
    if (loadCellInput.io()) {
      if (isOkToCalc) {
        if (!loadReading.io()) {
          loadReading.put(m * loadCellInput.get() + b)
        }
      } else {
        // not ok to calc, clear flow control anyways,
        loadCellInput.get()
      }
    }
  }
}