在VS2010中使用长双精度编译Windows C ++应用程序

Question

At work we have MSVS2010 Ultimate, and I'm writing a program which runs exhaustive simulations using real numbers. I'm getting non-trivial round-off errors and I've already taken reasonable steps to ensure my algorithm is as numerically stable as possible.

I'd like to switch to 128-bit quadruple precision floating point numbers (long double, right?), to see how much of a difference it makes.

I've replaced all relevant instances of double with long double , recompiled, and ran my dummy simulation again but have exactly the same result as before.

These are my (debug) compiler options as per my project property page in C/C++:

/ZI /nologo /W3 /WX- /Od /Oy- /D "_MBCS" /Gm /EHsc /RTC1 /GS /fp:precise /Zc:wchar_t /Zc:forScope /Fp"Debug\\FFTU.pch" /Fa"Debug\\" /Fo"Debug\\" /Fd"Debug\\vc100.pdb" /Gd /analyze- /errorReport:queue

My dev CPU is a Core2 Duo T7300 but the target machine will be an i7. Both installations are Windows 7 64-bit.

Answer 1

You could switch to a non-Microsoft compiler such as gcc , Borland, or Intel. Those all recognize long double as 80-bit extended precision, the native internal format of the 8087.