Utils.h

00001 /*
00002     File:           Utils.h
00003 
00004     Function:       Various math definitions for VL
00005 
00006     Author(s):      Andrew Willmott
00007 
00008     Copyright:      (c) 1995-2001, Andrew Willmott
00009  */
00010 
00011 #ifndef __VL_MATH__
00012 #define __VL_MATH__
00013 
00014 //#include <cstdlib>
00015 
00016 // --- Inlines ----------------------------------------------------------------
00017 
00018 // additions to arithmetic functions
00019 
00020 #ifdef VL_HAS_IEEEFP
00021 #include <ieeefp.h>
00022 #define vl_is_finite(X) finite(X)
00023 #elif defined (__GNUC__) && defined(__USE_MISC)
00024 #define vl_is_finite(X) finite(X)
00025 #else
00026 #define vl_is_finite(X) (1)
00027 #endif
00028 
00029 #ifdef VL_HAS_DRAND
00030 inline Double vl_rand()
00031 { return(drand48()); }
00032 #else
00033 #ifndef RAND_MAX
00034 // we're on something totally sucky, like SunOS
00035 #define RAND_MAX (Double(1 << 30) * 4.0 - 1.0)
00036 #endif
00037 inline Double vl_rand()
00038 { return(rand() / (RAND_MAX + 1.0)); }
00039 #endif
00040 
00041 #ifndef __CMATH__
00042 // GNU's complex.h defines its own abs(double)
00043 #ifdef VL_HAS_ABSF
00044 inline Float abs(Float x)
00045 { return (fabsf(x)); }
00046 #endif
00047 // jmc ......... 7/19
00048 //inline Double abs(Double x)
00049 //{ return (fabs(x)); }
00050 #endif
00051 #ifdef VL_HAS_ABSF
00052 inline Float len(Float x)
00053 { return (fabsf(x)); }
00054 #endif
00055 inline Double len(Double x)
00056 { return (fabs(x)); }
00057 
00058 inline Float sqrlen(Float r)
00059 { return(sqr(r)); }
00060 inline Double sqrlen(Double r)
00061 { return(sqr(r)); }
00062 
00063 inline Float mix(Float a, Float b, Float s)
00064 { return((1.0f - s) * a + s * b); }
00065 inline Double mix(Double a, Double b, Double s)
00066 { return((1.0 - s) * a + s * b); }
00067 
00068 inline Double sign(Double d)
00069 {
00070     if (d < 0)
00071         return(-1.0);
00072     else
00073         return(1.0);
00074 }
00075 
00076 // useful routines
00077 
00078 inline Bool IsPowerOfTwo(Int a)
00079 { return((a & -a) == a); };
00080 
00081 inline Void SetReal(Float &a, Double b)
00082 { a = Float(b); }
00083 inline Void SetReal(Double &a, Double b)
00084 { a = b; }
00085 
00086 #endif