I have the following head scratcher, demonstrated in jshell 11.0.12 and 17.0.1 here The same thing occurs in a simple compiled class in both versions Although 17 warns that strictfp is no longer required The JLS says this in section 5.1.2 In 14 it contained the following after the bullet list Based on my read…
Tag: floating-point
How can I intentionally create random floating point / decimal precision errors in java?
My goal is to generate random numbers that all have decimal precision errors. Here are some examples of types of numbers I would like to generate: Here are strategies I have tried. parseFloat(“4.01500000000000000001”); BigDecimal.valueOf(ThreadLocalRandom.current().nextFloat()).multiply(BigDecimal…
How likely is BigDecimal to cause memory issues for a POS program?
I understand that BigDecimal is the most accurate way to express currency because treating currency values as a floating-point data type tends to cause rounding errors. However, I also understand that BigDecimal calculations require more memory. That said, is using BigDecimal instead of float or double really…
Generating a random double in an exclusive range
I’m trying to generate a random floating point number between but not including it’s lower and upper bounds (lower, upper). I’ve seen a lot of questions about generating a number from, and including it’s lower bound up to, but not including it’s upper bound [lower, upper), but th…
C compatible printf output for Java
I’d want to convert float/double to string, in Java and C, such that the outputs are both consistent and user friendly. By “user friendly”, I mean the string should be human readable and sound: a maximum number of significant digits, and some automatic switching to scientific notation when a…
How can I handle precision error with float in Java?
I’m wondering what the best way to fix precision errors is in Java. As you can see in the following example, there are precision errors: The result displayed is: loop value: 11 20.789999 loop value: 22 41.579998 loop value: 44 83.159996 loop value: 88 166.31999 loop value: 176 332.63998 loop value: 352 …
How to get the decimal part of a float?
I need to extract the decimal part of a float number, but I get weird results: Why does this happen? Why do I get those values instead of 0.65? Answer float only has a few digit of precision so you should expect to see a round error fairly easily. try double this has more accuracy but still has rounding error…
Prevent round off in String.format(“%.2f”, doubleValue) in Java
How do I prevent String.format(“%.2f”, doubleValue); from rounding off (round half up algorithm) instead of just truncating it? e.g. after formatting, I just want to discard the last digit, I know there are other ways to do this, I just want to know if this is possible using the String.format. Ans…
When should I use the “strictfp” keyword in java?
I’ve looked up what this does, but does anyone actually have an example of when you would use the strictfp keyword in Java? Has anyone actually found a use for this? Would there be any side-effects of just putting it on all my floating point operations? Answer Strictfp ensures that you get exactly the s…