Related to my other question, I have now modified the sparse matrix solver to use the SOR (Successive Over-Relaxation) method. The code is now as follows: void SORSolver::step() { float const omega = 1.0f; float const *b = &d_b(1, 1), *w = &d_w(1, 1), *e = &d_e(1, 1), *s = &d_s(1, 1), *n = &d_n(1, 1), *xw...
double d; scanf("%f", &d); printf("%f", d); result: input: 10.3 output: 0.00000 Why? i think output should be 10.3 visual studio 2008. ...
How would I go about manually changing a decimal (base 10) number into IEEE 754 single-precision floating-point format? I understand that there is three parts to it, a sign, a exponential, and a mantissa. I just don't completely understand what the last two parts actually represent. Thanks, Rob ...
I have some software written in VB.NET that performs a lot of calculations, mostly extracting jpegs to bitmaps and computing calculations on the pixels like convolutions and matrix multiplication. Different computers are giving me different results despite having identical inputs. What might be the reason? Edit: I can't provide the al...
(int)(33.46639 * 1000000) returns 33466389 Why does this happen? ...
I am doing some input/output between a c++ and a python program (only floating point values) python has a nice feature of converting floating point values to hex-numbers and back as you can see in this link: http://docs.python.org/library/stdtypes.html#additional-methods-on-float Is there an easy way in C++ to to something similar? and...
Say you have 100000000 32-bit floating point values in an array, and each of these floats has a value between 0.0 and 1.0. If you tried to sum them all up like this result = 0.0; for (i = 0; i < 100000000; i++) { result += array[i]; } you'd run into problems as result gets much larger than 1.0. So what are some of the ways to mor...
Is there a fast method for taking the modulus of a floating point number? With integers, there are tricks for Mersenne primes, so that its possible to calculate y = x MOD 2^31-1 without needing division. integer trick Can any similar tricks be applied for floating point numbers? Preferably, in a way that can be converted into vect...
The default floating point type in Java is the double. If you hard code a constant like 2.5 into your program, Java makes it a double automatically. When you do an operation on floats or ints that could potentially benefit from more precision, the type is 'promoted' to a double. But in the Android API, everything seems to be a float f...
There is some problem, i can't understand anyway. look at this code please <script type="text/javascript"> function math(x) { var y; y = x*10; alert(y); } </script> <input type="button" onclick="math(0.011)"> What must be alerted after i click on button? i think 0.11, but no, it alerts 0.10999999999999999 explain please this...
I need to represent an IEEE 754-1985 double (64-bit) floating point number in a human-readable textual form, with the condition that the textual form can be parsed back into exactly the same (bit-wise) number. Is this possible/practical to do without just printing the raw bytes? If yes, code to do this would be much appreciated. ...
What's the best heuristic I can use to identify whether a chunk of X 4-bytes are integers or floats? A human can do this easily, but I wanted to do it programmatically. I realize that since every combination of bits will result in a valid integer and (almost?) all of them will also result in a valid float, there is no way to know for su...
Hi, After searching a long time for a performance bug, I read about denormal floating point values. I have an Intel Core 2 Duo and I am compiling with gcc, using "-O2". So what do I do? Can I somehow instruct g++ to avoid denormal values? If not, can I somehow test if a float is denormal? Thanks! Nathan ...
try it out: volatile float bob = -344.0f; unsigned int fred = (unsigned int)bob; printf("%d\n",fred); output will be 0. obviously I am expecting it to wrap around just as if I had cast from a signed int to an unsgined int (which does wrap and act as expected on the iphone) we assume it is something to do with the floating point set...
I am aware of how floating point precision works in the regular cases, but I stumbled on an odd situation in my C# code. Why aren't result1 and result2 the exact same floating point value here? const float A; // Arbitrary value const float B; // Arbitrary value float result1 = (A*B)*dt; float result2 = (A*B); result2 *= dt; F...
Here's a piece of code that takes most time in my program, according to timeit statistics. It's a dirty function to convert floats in [-1.0, 1.0] interval into unsigned integer [0, 2**32]. How can I accelerate floatToInt? piece = [] rng = range(32) for i in rng: piece.append(1.0/2**i) def floatToInt(x): n = x + 1.0 res = 0 ...
I am storing a list of numbers (as Double) in a text file, then reading them out again. When I read them out of the text file however, the numbers are placed into the text box as 1.59993499 for example, instead of 1.6. AssignFile(Pipe, 'EconomicData.data'); Reset(Pipe); For i := 1 to 15 Do ReadLn(Pipe, SavedValue[i]); Close...
I read the JVM specification for the fpstrict modifier but still don't fully understand what it means. Can anyone enlighten me? ...
Searching online, I have found the following routine for calculating the sign of a float in IEEE format. This could easily be extended to a double, too. // returns 1.0f for positive floats, -1.0f for negative floats, 0.0f for zero inline float fast_sign(float f) { if (((int&)f & 0x7FFFFFFF)==0) return 0.f; // test exponent & mantis...
Hi, guys. Here is the example with comments: class Program { // first version of structure public struct D1 { public double d; public int f; } // during some changes in code then we got D2 from D1 // Field f type became double while it was int before public struct D2 { public dou...