implement WFA algorithm

This commit is contained in:
Arthur Lu 2024-03-25 21:29:30 +00:00
commit 685f43c19b
5 changed files with 401 additions and 0 deletions

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.eslintrc.json Normal file
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{
"env": {
"es2021": true,
"node": true
},
"extends": "standard",
"parserOptions": {
"ecmaVersion": "latest",
"sourceType": "module"
},
"rules": {
"no-tabs": [
"error",
{
"allowIndentationTabs": true
}
],
"indent": [
"error",
"tab"
],
"linebreak-style": [
"error",
"unix"
],
"quotes": [
"error",
"double"
],
"semi": [
"error",
"always"
],
"brace-style": [
"error",
"stroustrup",
{
"allowSingleLine": false
}
],
"camelcase": 0
}
}

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.gitignore vendored Normal file
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**/package-lock.json
**/node_modules

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package.json Normal file
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{
"name": "wfa-js",
"version": "0.0.1",
"description": "Wavefront alignment algorithm in JS",
"main": "src/main.js",
"type": "module",
"dependencies": {},
"devDependencies": {
"eslint": "^8.43.0",
"eslint-config-standard": "^17.1.0",
"eslint-plugin-import": "^2.27.5",
"eslint-plugin-n": "^16.0.1",
"eslint-plugin-promise": "^6.1.1"
},
"scripts": {
"lint": "DEBUG=eslint:cli-engine eslint --fix ."
}
}

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src/main.js Normal file
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import wf_align from "./wfa.js";
const p = {
x: 4,
o: 6,
e: 2
};
// this should be score=24, Alignment=XDIX
console.time("time")
const {CIGAR, score} = wf_align("TCTTTACTCGCGCGTTGGAGAAATACAATAGT", "TCTATACTGCGCGTTTGGAGAAATAAAATAGT", p)
console.timeEnd("time")
console.log(`score: ${score}`);
console.log(`CIGAR: ${CIGAR}`);

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src/wfa.js Normal file
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class WavefrontComponent {
constructor () {
this.lo = [0]; // lo for each wavefront
this.hi = [0]; // hi for each wavefront
this.W = []; // wavefront diag distance for each wavefront
this.A = []; // compact CIGAR for backtrace
}
// get value for wavefront=score, diag=k
get_val (score, k) {
if (this.W[score] !== undefined && this.W[score][k] !== undefined) {
return this.W[score][k];
}
else {
return NaN;
}
}
// set value for wavefront=score, diag=k
set_val (score, k, val) {
if (this.W[score]) {
this.W[score][k] = val;
}
else {
this.W[score] = [];
this.W[score][k] = val;
}
}
// get alignment traceback
get_traceback (score, k) {
if (this.A[score] !== undefined && this.A[score][k] !== undefined) {
return this.A[score][k];
}
else {
return undefined;
}
}
// set alignment traceback
set_traceback (score, k, traceback) {
if (this.A[score]) {
this.A[score][k] = traceback;
}
else {
this.A[score] = [];
this.A[score][k] = traceback;
}
}
// get hi for wavefront=score
get_hi (score) {
const hi = this.hi[score];
return isNaN(hi) ? 0 : hi;
}
// set hi for wavefront=score
set_hi (score, hi) {
this.hi[score] = hi;
}
// get lo for wavefront=score
get_lo (score) {
const lo = this.lo[score];
return isNaN(lo) ? 0 : lo;
}
// set lo for wavefront=score
set_lo (score, lo) {
this.lo[score] = lo;
}
// string representation of all wavefronts
toString () {
const traceback_str = ["OI", "EI", "OD", "ED", "SB", "IN", "DL", "EN"];
let s = "<";
let min_lo = Infinity;
let max_hi = -Infinity;
// get the min lo and max hi values across all wavefronts
for (let i = 0; i < this.W.length; i++) {
const lo = this.lo[i];
const hi = this.hi[i];
if (lo < min_lo) {
min_lo = lo;
}
if (hi > max_hi) {
max_hi = hi;
}
}
// print out two headers, one for wavefront and one for traceback
for (let k = min_lo; k <= max_hi; k++) {
s += FormatNumberLength(k, 2);
if (k < max_hi) {
s += "|";
}
}
s += ">\t<"
for (let k = min_lo; k <= max_hi; k++) {
s += FormatNumberLength(k, 2);
if (k < max_hi) {
s += "|";
}
}
s += ">\n";
// for each wavefront
for (let i = 0; i < this.W.length; i++) {
s += "[";
const lo = this.lo[i];
const hi = this.hi[i];
// print out the wavefront matrix
for (let k = min_lo; k <= max_hi; k++) {
if (this.W[i] !== undefined && this.W[i][k] !== undefined && !isNaN(this.W[i][k])) {
s += FormatNumberLength(this.W[i][k], 2);
}
else if (k < lo || k > hi) {
s += "--";
}
else {
s += " ";
}
if (k < max_hi) {
s += "|";
}
}
s += "]\t[";
// print out the traceback matrix
for (let k = min_lo; k <= max_hi; k++) {
if (this.A[i] !== undefined && this.A[i][k] !== undefined) {
s += traceback_str[this.A[i][k].toString()];
}
else if (k < lo || k > hi) {
s += "--";
}
else {
s += " ";
}
if (k < max_hi) {
s += "|";
}
}
s += "]\n";
}
return s;
}
}
const traceback = {
OpenIns: 0,
ExtdIns: 1,
OpenDel: 2,
ExtdDel: 3,
Sub: 4,
Ins: 5,
Del: 6,
End: 7,
}
function FormatNumberLength (num, length) {
let r = "" + num;
while (r.length < length) {
r = " " + r;
}
return r;
}
function min (args) {
args.forEach((el, idx, arr) => {
arr[idx] = isNaN(el) ? Infinity : el;
});
const min = Math.min.apply(Math, args);
return min === Infinity ? NaN : min;
}
function max (args) {
args.forEach((el, idx, arr) => {
arr[idx] = isNaN(el) ? -Infinity : el;
});
const max = Math.max.apply(Math, args);
return max === -Infinity ? NaN : max;
}
function argmin (args) {
const val = min(args)
return args.indexOf(val);
}
function argmax (args) {
const val = max(args)
return args.indexOf(val);
}
export default function wf_align (s1, s2, penalties) {
const n = s1.length;
const m = s2.length;
const A_k = m - n;
const A_offset = m;
let score = 0;
const M = new WavefrontComponent();
M.set_val(0, 0, 0);
M.set_hi(0, 0);
M.set_lo(0, 0);
M.set_traceback(0, 0, traceback.End)
const I = new WavefrontComponent();
const D = new WavefrontComponent();
while (true) {
wf_extend(M, s1, n, s2, m, score);
if (M.get_val(score, A_k) >= A_offset) {
break;
}
score++;
wf_next(M, I, D, score, penalties);
}
return wf_backtrace(M, I, D, score, penalties, A_k, A_offset);
}
function wf_extend (M, s1, n, s2, m, score) {
const lo = M.get_lo(score);
const hi = M.get_hi(score);
for (let k = lo; k <= hi; k++) {
let v = M.get_val(score, k) - k;
let h = M.get_val(score, k);
if (isNaN(v) || isNaN(h)) {
continue;
}
while (s1[v] === s2[h]) {
M.set_val(score, k, M.get_val(score, k) + 1);
v++;
h++;
if (v > n || h > m) {
break;
}
}
}
}
function wf_next (M, I, D, score, penalties) {
const x = penalties.x;
const o = penalties.o;
const e = penalties.e;
const lo = min([M.get_lo(score - x), M.get_lo(score - o - e), I.get_lo(score - e), D.get_lo(score - e)]) - 1;
const hi = max([M.get_hi(score - x), M.get_hi(score - o - e), I.get_hi(score - e), D.get_hi(score - e)]) + 1;
M.set_hi(score, hi);
I.set_hi(score, hi);
D.set_hi(score, hi);
M.set_lo(score, lo);
I.set_lo(score, lo);
D.set_lo(score, lo);
for (let k = lo; k <= hi; k++) {
I.set_val(score, k, max([
M.get_val(score - o - e, k - 1),
I.get_val(score - e, k - 1)
]) + 1);
I.set_traceback(score, k, [traceback.OpenIns, traceback.ExtdIns][argmax([
M.get_val(score - o - e, k - 1),
I.get_val(score - e, k - 1)
])])
D.set_val(score, k, max([
M.get_val(score - o - e, k + 1),
D.get_val(score - e, k + 1)
]));
D.set_traceback(score, k, [traceback.OpenDel, traceback.ExtdDel][argmax([
M.get_val(score - o - e, k + 1),
D.get_val(score - e, k + 1)
])])
M.set_val(score, k, max([
M.get_val(score - x, k) + 1,
I.get_val(score, k),
D.get_val(score, k)
]));
M.set_traceback(score, k, [traceback.Sub, traceback.Ins, traceback.Del][argmax([
M.get_val(score - x, k) + 1,
I.get_val(score, k),
D.get_val(score, k)
])]);
}
}
function wf_backtrace (M, I, D, score, penalties, A_k) {
const traceback_CIGAR = ["I", "I", "D", "D", "X", "", "", ""];
const x = penalties.x;
const o = penalties.o;
const e = penalties.e;
let CIGAR_rev = ""; // reversed CIGAR
let tb_s = score; // traceback score
let tb_k = A_k; // traceback diag k
let current_traceback = M.get_traceback(tb_s, tb_k);
let done = false;
while (!done) {
CIGAR_rev += traceback_CIGAR[current_traceback];
switch (current_traceback) {
case traceback.OpenIns:
tb_s = tb_s - o - e;
tb_k = tb_k - 1;
current_traceback = M.get_traceback(tb_s, tb_k);
break;
case traceback.ExtdIns:
tb_s = tb_s - e;
tb_k = tb_k - 1;
current_traceback = I.get_traceback(tb_s, tb_k);
break;
case traceback.OpenDel:
tb_s = tb_s - o - e;
tb_k = tb_k + 1;
current_traceback = M.get_traceback(tb_s, tb_k);
break;
case traceback.ExtdDel:
tb_s = tb_s - e;
tb_k = tb_k + 1;
current_traceback = D.get_traceback(tb_s, tb_k);
break;
case traceback.Sub:
tb_s = tb_s - x;
tb_k = tb_k;
current_traceback = M.get_traceback(tb_s, tb_k);
break;
case traceback.Ins:
tb_s = tb_s;
tb_k = tb_k;
current_traceback = I.get_traceback(tb_s, tb_k);
break;
case traceback.Del:
tb_s = tb_s;
tb_k = tb_k;
current_traceback = D.get_traceback(tb_s, tb_k)
break;
case traceback.End:
done = true
break;
}
}
const CIGAR = Array.from(CIGAR_rev).reverse().join("");
return {CIGAR, score};
}