molstar
Version:
A comprehensive macromolecular library.
75 lines (74 loc) • 2.27 kB
JavaScript
/**
* Copyright (c) 2018-2019 mol* contributors, licensed under MIT, See LICENSE file for more info.
*
* @author David Sehnal <david.sehnal@gmail.com>
* @author Alexander Rose <alexander.rose@weirdbyte.de>
*/
/**
* Determine the number of digits in a floating point number
* Find a number M such that round(M * v) - M * v <= delta.
* If no such M exists, return -1.
*/
export function getMantissaMultiplier(v, maxDigits, delta) {
var m = 1, i;
for (i = 0; i < maxDigits; i++) {
var mv = m * v;
if (Math.abs(Math.round(mv) - mv) <= delta)
return i;
m *= 10;
}
return -1;
}
export function integerDigitCount(v, delta) {
var f = Math.abs(v);
if (f < delta)
return 0;
return Math.floor(Math.log10(Math.abs(v))) + 1;
}
/**
* Determine the maximum number of digits in a floating point array.
* Find a number M such that round(M * v) - M * v <= delta.
* If no such M exists, return -1.
*/
export function getArrayDigitCount(xs, maxDigits, delta) {
var mantissaDigits = 1;
var integerDigits = 0;
for (var i = 0, _i = xs.length; i < _i; i++) {
if (mantissaDigits >= 0) {
var t = getMantissaMultiplier(xs[i], maxDigits, delta);
if (t < 0)
mantissaDigits = -1;
else if (t > mantissaDigits)
mantissaDigits = t;
}
var abs = Math.abs(xs[i]);
if (abs > delta) {
var d = Math.floor(Math.log10(Math.abs(abs))) + 1;
if (d > integerDigits)
integerDigits = d;
}
}
return { mantissaDigits: mantissaDigits, integerDigits: integerDigits };
}
export function isInteger(s) {
s = s.trim();
var n = parseInt(s, 10);
return isNaN(n) ? false : n.toString() === s;
}
export function getPrecision(v) {
if (!isFinite(v))
return 0;
var e = 1;
var p = 0;
while (Math.round(v * e) / e !== v) {
e *= 10;
++p;
}
return p;
}
export function toPrecision(v, precision) {
return parseFloat(v.toPrecision(precision));
}
export function toFixed(v, fractionDigits) {
return parseFloat(v.toFixed(fractionDigits));
}