Decimal(0).next_plus() # smallest denorm Decimal('1E-1000026') with default settingsĭecimal(0).next_plus()/2 # underflows to zeroĭecimal instances also use more than four times the memory of a float: sys.getsizeof(Decimal(0))/sys.getsizeof(0.0)Īlso many float operations are performed directly by the CPU, and are very fast, while Decimal has to be emulated in software. It is fixed to the precision of C doubles.īut both Decimal and float have the same overflow and underflow issues. The built-in float type is an object-oriented wrapper on the platform C double type, a 64 bit floating point number. For example, trying to print a string of 999999999999999999 digits would require more than 888 petabytes of memory just for the string. There are still hard limits: the maximum precision is 425000000 digits on 32-bit platforms, and 999999999999999999 digits on 64-bit platforms.Īlthough I imagine you might run out of memory long before you can work with that many digits. So it is limited only by the amount of memory available.ĭecimal is a floating point number like float, the big differences are that it uses base-10 and it has user-configurable arbitrary precision. If I remember correctly, int uses an array of bytes as a base-256 number. If you need more than one myPow, you can give them a suffix or prefix: def mypow_using_exponentiation(x, n): So instead of making myPow a method of some class, you should consider just making it a function. In another language, we might use a record or a struct for these method-less values.) (Classes which only provide state with no, or minimal, behaviour are probably more common. If a class has no state (like your Solution50 class), or no methods, then chances are very good that the class isn’t pulling its weight and should be removed. The general guideline is that every class should have both state (data) and behaviour (one or more methods).

The classes often don’t do anything except hold that method. In Java, every function has to be put into a method of some class. It reads like you are trying to program Java in Python. Its probably just a case of somebody thought it was a good idea at the time.īy the way, each of the builtin exponent operator **, the pow() builtin function, and math.pow function round 2.0 to the power of (negative huge number) to 0.0.īy the way, you have two classes which do nothing and exist for no reason other than to hold a function. There’s probably no real logic behind the difference. Floating point multiplication in Python must follow the rules set up by the IEEE-754 standard, which has multiplication overflow to the special value float(‘inf’).īut for reasons now lost, whoever designed Python’s exponent operator, and the pow() function, made a different decision to raise OverflowError instead. That is probably buried deep, deep in the mists of history, when Python was first written. Why the difference between multiplication and exponentiation? Which rounds to zero, so you get the final result of 0.0. For brevity I won’t write them all down in full: While the second computes the similar sequence, but using multiplication. Your first method tries to compute the sequence of powers: The two methods behave differently because they are written differently, one uses the exponentiation operator ** and the other just uses multiplication.

Integer overflow error java