You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
43 lines
1.3 KiB
43 lines
1.3 KiB
3 years ago
|
/* frac.js (C) 2012-present SheetJS -- http://sheetjs.com */
|
||
|
|
var frac = function frac(x, D, mixed) {
|
||
|
|
var n1 = Math.floor(x), d1 = 1;
|
||
|
|
var n2 = n1+1, d2 = 1;
|
||
|
|
if(x !== n1) while(d1 <= D && d2 <= D) {
|
||
|
|
var m = (n1 + n2) / (d1 + d2);
|
||
|
|
if(x === m) {
|
||
|
|
if(d1 + d2 <= D) { d1+=d2; n1+=n2; d2=D+1; }
|
||
|
|
else if(d1 > d2) d2=D+1;
|
||
|
|
else d1=D+1;
|
||
|
|
break;
|
||
|
|
}
|
||
|
|
else if(x < m) { n2 = n1+n2; d2 = d1+d2; }
|
||
|
|
else { n1 = n1+n2; d1 = d1+d2; }
|
||
|
|
}
|
||
|
|
if(d1 > D) { d1 = d2; n1 = n2; }
|
||
|
|
if(!mixed) return [0, n1, d1];
|
||
|
|
var q = Math.floor(n1/d1);
|
||
|
|
return [q, n1 - q*d1, d1];
|
||
|
|
};
|
||
|
|
frac.cont = function cont(x, D, mixed) {
|
||
|
|
var sgn = x < 0 ? -1 : 1;
|
||
|
|
var B = x * sgn;
|
||
|
|
var P_2 = 0, P_1 = 1, P = 0;
|
||
|
|
var Q_2 = 1, Q_1 = 0, Q = 0;
|
||
|
|
var A = Math.floor(B);
|
||
|
|
while(Q_1 < D) {
|
||
|
|
A = Math.floor(B);
|
||
|
|
P = A * P_1 + P_2;
|
||
|
|
Q = A * Q_1 + Q_2;
|
||
|
|
if((B - A) < 0.00000005) break;
|
||
|
|
B = 1 / (B - A);
|
||
|
|
P_2 = P_1; P_1 = P;
|
||
|
|
Q_2 = Q_1; Q_1 = Q;
|
||
|
|
}
|
||
|
|
if(Q > D) { if(Q_1 > D) { Q = Q_2; P = P_2; } else { Q = Q_1; P = P_1; } }
|
||
|
|
if(!mixed) return [0, sgn * P, Q];
|
||
|
|
var q = Math.floor(sgn * P/Q);
|
||
|
|
return [q, sgn*P - q*Q, Q];
|
||
|
|
};
|
||
|
|
// eslint-disable-next-line no-undef
|
||
|
|
if(typeof module !== 'undefined' && typeof DO_NOT_EXPORT_FRAC === 'undefined') module.exports = frac;
|