Check if BigInteger is not a perfect square has code to compute the integer square root of a Java BigInteger. Here it is translated into C#, as an extension method. public static BigInteger Sqrt(this BigInteger n) { if (n == 0) return 0; if (n > 0) { int bitLength = Convert.ToInt32(Math.Ceiling(BigInteger.Log(n, 2))); BigInteger root … Read more
The GNU Multiple Precision Arithmetic Library does what you want http://gmplib.org/ Gnu MP is a C library but it has a C++ class Interface and if you are interested only in big integers, you may just deal with mpz_class. Look at the sample below which I took from the page C++ Interface General int main … Read more
In case you don’t want to return a BigInt, then the following might work for you too: function log10(bigint) { if (bigint < 0) return NaN; const s = bigint.toString(10); return s.length + Math.log10(“0.” + s.substring(0, 15)) } function log(bigint) { return log10(bigint) * Math.log(10); } function natlog(bigint) { if (bigint < 0) return NaN; … Read more
You can use the NSDecimalNumber class from Cocoa. It is not infinite precision, but it can represent 38 decimal digits of precision, which may be enough for what you need.
You have a parameterized constructor for that. BigDecimal(BigInteger val)
I can see four basic ways that double can screw you when dealing with currency calculations. Mantissa Too Small With ~15 decimal digits of precision in the mantissa, you are you going to get the wrong result any time you deal with amounts larger than that. If you are tracking cents, problems would start to … Read more
I recently ran into this and found the most reasonable solution to simply cast any UNSIGNED ints as SIGNED. SELECT *, ((1 / log(1301980250 – cast(date as signed)) * 175) as weight FROM news_articles ORDER BY weight
The value is actually not exceeding the maximum numeric value in JavaScript (which is “only” 1.7308 or so). However, the value is exceeding the range of “integral precision”. It is not that the wrong number is sent: rather, it is that the literal 12000000000002539 can only be represented as precisely as 12000000000002540, and thus there … Read more
Just for fun: public static BigInteger sqrt(BigInteger x) { BigInteger div = BigInteger.ZERO.setBit(x.bitLength()/2); BigInteger div2 = div; // Loop until we hit the same value twice in a row, or wind // up alternating. for(;;) { BigInteger y = div.add(x.divide(div)).shiftRight(1); if (y.equals(div) || y.equals(div2)) return y; div2 = div; div = y; } }
The difference is purely in the maximum value which can be stored (18,446,744,073,709,551,615 for the bigint(20) and 4,294,967,295 for the int(10), I believe), as per the details on the MySQL Numeric Types manual page. Incidentally, the use of (20) and (10) is largely irrelevant unless you’re using ZEROFILL. (i.e.: It doesn’t actually change the size … Read more