First, if this variable is to be updated after (nearly) every instruction, the obvious piece of advice is this: don’t Only update it when the subsequent instructions need its value. At any other time, there’s no point in updating it. But anyway, when we update it, what we want is this behavior: R < 0 … Read more
Java floating point is based on the IEEE 754 binary floating point standard Floating Point Standard, the first version of which was issued in about 1985, so it is much older than Java. Given widespread hardware implementation of IEEE 754 by the time Java was being defined, the Java creators had little choice. Each IEEE … Read more
You’d have to write your own implementation of Iterable<Boolean> which took an array of bytes, and then created Iterator<Boolean> values which remembered the current index into the byte array and the current index within the current byte. Then a utility method like this would come in handy: private static Boolean isBitSet(byte b, int bit) { … Read more
In a bit wise XOR operation: a b a^b ———– 0 0 0 0 1 1 1 0 1 1 1 0 XOR sum refers to successive XOR operations on integers. Suppose you have numbers from 1 to N and you have to find their XOR sum then for N = 6, XOR sum will … Read more
As indicated in comments, real*8 isn’t standard Fortran. This FAQ entry has more details. That said, once we’re into the non-standard realm… The 8 refers to the number of bytes that the data type uses. So a 32-bit integer is integer*4 along the same lines. (But is also non-standard.) A quick search found this guide … Read more
from bitarray import bitarray a = bitarray(2**20) You can check out more info about this module at http://pypi.python.org/pypi/bitarray/
I’m not familiar with either of these books, but the second is closer to current reality. The first may be discussing a specific processor. Processors have been made with quite a variety of word sizes, not always a multiple of 8. The 8086 and 8087 processors used 16 bit words, and it’s likely this is … Read more
Something like this: SUM(CASE WHEN ColumnName = 1 THEN 1 ELSE 0 END) AS Pass, SUM(CASE WHEN ColumnName = 0 THEN 1 ELSE 0 END) AS Fail
convert to base 2: var base2 = (yourNumber).toString(2); access the characters (bits): base2[0], base2[1], base2[3], etc…
An integer is represented as a sequence of bits in memory. For interaction with humans, the computer has to display it as decimal digits, but all the calculations are carried out as binary. 123 in decimal is stored as 1111011 in memory. The & operator is a bitwise “And”. The result is the bits that … Read more