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| string is not a member of 'std' ... and divide by zero http://forum.alglib.net/viewtopic.php?f=2&t=856 |
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| Author: | Sergey.Bochkanov [ Tue May 28, 2013 8:09 am ] |
| Post subject: | Re: string is not a member of 'std' ... and divide by zero |
Hello! 1. situation with std::string is something specific for C++ Builder. Unfortunately, we have not tested ALGLIB with newer versions of C++ Builder. string class must be part of std, and I think that it can be fixed by including appropriate files - I just do not have a copy of C++ Builder to experiment with. 2. regarding division by zero. It occurs when all Y[] are same, and total sum-of-squares is zero. Most C++ and C# compilers are compliant with IEEE 754 standard and handle it by returning NAN as result (that's why it was not caught), but C++ Builder raises an exception (I think that it is NOT correct behavior) unless you manually mask floating-point exceptions. As I told, IEEE 754 compliant should handle it gracefully, but I decided to regard it as a minor bug. It was added to issues tracker http://bugs.alglib.net/view.php?id=524 and will be fixed in upcoming 3.8.0 As for you, you may: (a) manually mask FP exceptions when your program starts (recommended) (b) replace "rep->r2 = 1.0 - rss/tss;" by "rep->r2 = tss>0 ? 1.0 - rss/tss : 1.0;" |
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