trigtbl.h

来自「开放源码的编译器open watcom 1.6.0版的源代码」· C头文件 代码 · 共 165 行

/*
** Please only distribute this with it's associated FHT routine.
** This algorithm is apparently patented(!) and the code copyrighted. 
** See the comment with the fht routine for more info.
**  -Thanks,
**   Ron Mayer
*/

#ifdef REAL
#else
#define REAL double
#endif

#ifdef GOOD_TRIG
#else
#define FAST_TRIG
#endif

#if defined(GOOD_TRIG)
#define FHT_SWAP(a,b,t) {(t)=(a);(a)=(b);(b)=(t);}
#define TRIG_VARS                                                \
      int t_lam=0;
#define TRIG_INIT(k,c,s)                                         \
     {                                                           \
      int i;                                                     \
      for (i=2 ; i<=k ; i++)                                     \
	  {coswrk[i]=costab[i];sinwrk[i]=sintab[i];}             \
      t_lam = 0;                                                 \
      c = 1;                                                     \
      s = 0;                                                     \
     }
#define TRIG_NEXT(k,c,s)                                         \
     {                                                           \
	 int i,j;                                                \
	 (t_lam)++;                                              \
	 for (i=0 ; !((1<<i)&t_lam) ; i++);                      \
	 i = k-i;                                                \
	 s = sinwrk[i];                                          \
	 c = coswrk[i];                                          \
	 if (i>1)                                                \
	    {                                                    \
	     for (j=k-i+2 ; (1<<j)&t_lam ; j++);                 \
	     j         = k - j;                                  \
	     sinwrk[i] = halsec[i] * (sinwrk[i-1] + sinwrk[j]);  \
	     coswrk[i] = halsec[i] * (coswrk[i-1] + coswrk[j]);  \
	    }                                                    \
     }
#define TRIG_RESET(k,c,s)
#endif

#if defined(FAST_TRIG)
#define TRIG_VARS                                        \
      REAL t_c,t_s;
#define TRIG_INIT(k,c,s)                                 \
    {                                                    \
     t_c  = costab[k];                                   \
     t_s  = sintab[k];                                   \
     c    = 1;                                           \
     s    = 0;                                           \
    }
#define TRIG_NEXT(k,c,s)                                 \
    {                                                    \
     REAL t = c;                                         \
     c   = t*t_c - s*t_s;                                \
     s   = t*t_s + s*t_c;                                \
    }
#define TRIG_RESET(k,c,s)
#endif

static REAL halsec[20]=
    {
     0,
     0,
     .54119610014619698439972320536638942006107206337801,
     .50979557910415916894193980398784391368261849190893,
     .50241928618815570551167011928012092247859337193963,
     .50060299823519630134550410676638239611758632599591,
     .50015063602065098821477101271097658495974913010340,
     .50003765191554772296778139077905492847503165398345,
     .50000941253588775676512870469186533538523133757983,
     .50000235310628608051401267171204408939326297376426,
     .50000058827484117879868526730916804925780637276181,
     .50000014706860214875463798283871198206179118093251,
     .50000003676714377807315864400643020315103490883972,
     .50000000919178552207366560348853455333939112569380,
     .50000000229794635411562887767906868558991922348920,
     .50000000057448658687873302235147272458812263401372
    };
static REAL costab[20]=
    {
     .00000000000000000000000000000000000000000000000000,
     .70710678118654752440084436210484903928483593768847,
     .92387953251128675612818318939678828682241662586364,
     .98078528040323044912618223613423903697393373089333,
     .99518472667219688624483695310947992157547486872985,
     .99879545620517239271477160475910069444320361470461,
     .99969881869620422011576564966617219685006108125772,
     .99992470183914454092164649119638322435060646880221,
     .99998117528260114265699043772856771617391725094433,
     .99999529380957617151158012570011989955298763362218,
     .99999882345170190992902571017152601904826792288976,
     .99999970586288221916022821773876567711626389934930,
     .99999992646571785114473148070738785694820115568892,
     .99999998161642929380834691540290971450507605124278,
     .99999999540410731289097193313960614895889430318945,
     .99999999885102682756267330779455410840053741619428
    };
static REAL sintab[20]=
    {
     1.0000000000000000000000000000000000000000000000000,
     .70710678118654752440084436210484903928483593768846,
     .38268343236508977172845998403039886676134456248561,
     .19509032201612826784828486847702224092769161775195,
     .09801714032956060199419556388864184586113667316749,
     .04906767432741801425495497694268265831474536302574,
     .02454122852291228803173452945928292506546611923944,
     .01227153828571992607940826195100321214037231959176,
     .00613588464915447535964023459037258091705788631738,
     .00306795676296597627014536549091984251894461021344,
     .00153398018628476561230369715026407907995486457522,
     .00076699031874270452693856835794857664314091945205,
     .00038349518757139558907246168118138126339502603495,
     .00019174759731070330743990956198900093346887403385,
     .00009587379909597734587051721097647635118706561284,
     .00004793689960306688454900399049465887274686668768
    };
static REAL coswrk[20]=
    {
     .00000000000000000000000000000000000000000000000000,
     .70710678118654752440084436210484903928483593768847,
     .92387953251128675612818318939678828682241662586364,
     .98078528040323044912618223613423903697393373089333,
     .99518472667219688624483695310947992157547486872985,
     .99879545620517239271477160475910069444320361470461,
     .99969881869620422011576564966617219685006108125772,
     .99992470183914454092164649119638322435060646880221,
     .99998117528260114265699043772856771617391725094433,
     .99999529380957617151158012570011989955298763362218,
     .99999882345170190992902571017152601904826792288976,
     .99999970586288221916022821773876567711626389934930,
     .99999992646571785114473148070738785694820115568892,
     .99999998161642929380834691540290971450507605124278,
     .99999999540410731289097193313960614895889430318945,
     .99999999885102682756267330779455410840053741619428
    };
static REAL sinwrk[20]=
    {
     1.0000000000000000000000000000000000000000000000000,
     .70710678118654752440084436210484903928483593768846,
     .38268343236508977172845998403039886676134456248561,
     .19509032201612826784828486847702224092769161775195,
     .09801714032956060199419556388864184586113667316749,
     .04906767432741801425495497694268265831474536302574,
     .02454122852291228803173452945928292506546611923944,
     .01227153828571992607940826195100321214037231959176,
     .00613588464915447535964023459037258091705788631738,
     .00306795676296597627014536549091984251894461021344,
     .00153398018628476561230369715026407907995486457522,
     .00076699031874270452693856835794857664314091945205,
     .00038349518757139558907246168118138126339502603495,
     .00019174759731070330743990956198900093346887403385,
     .00009587379909597734587051721097647635118706561284,
     .00004793689960306688454900399049465887274686668768
    };