I’m the author of xlrd. There is so much confusion in other answers and comments to rebut in comments so I’m doing it in an answer. @katriealex: “””precision being lost in the guts of xlrd””” — entirely unfounded and untrue. xlrd reproduces exactly the 64-bit float that’s stored in the XLS file. @katriealex: “””It may … Read more
Try using String.format(Locale.US, “%f”, floatValue) for just setting locale used during formatting.
Yes, -Float.MAX_VALUE is the negative number with largest magnitude. floats are represented the same way as doubles, just with half the storage space (and the accompanying loss of precision.) Since signs in IEEE 754 are represented by a single bit, flipping that bit doesn’t change the overall magnitude attainable by the remaining bits.
The issue with LL m = pow(2, n + 1) – 2; is that pow(2, n + 1) is not a long long. It has the type double (refer to cppreference) and because the value is so large, subtracting 2 from it will not change its value. That means that m will not have the … Read more
Math.Round Method (Decimal, Int32) Example: Math.Round(3.44, 1); //Returns 3.4.
std::atomic<double> is supported in the sense that you can create one in your program and it will work under the rules of C++11. You can perform loads and stores with it and do compare-exchange and the like. The standard specifies that arithmetic operations (+, *, +=, &, etc.) are only provided for atomics of “integral … Read more
There’s no problem using floats as dict keys. Just round(n, 1) them to normalise them to your keyspace. eg. >>> hash(round(6.84, 1)) 3543446220 >>> hash(round(6.75, 1)) 3543446220
The best reference is the Intel Optimization Manual, which provides fairly detailed information on architectural hazards and instruction latencies for all recent Intel cores, as well as a good number of optimization examples. Another excellent reference is Agner Fog’s optimization resources, which have the virtue of also covering AMD cores. Note that specific cost models … Read more