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sqrt() speed up.

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git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@4444 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
This commit is contained in:
shigek 2003-08-26 12:48:13 +00:00
parent be297cff9b
commit e0a51801f8
1 changed files with 23 additions and 25 deletions
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48
ext/bigdecimal/bigdecimal.c
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@ -215,7 +215,6 @@ BigDecimal_mode(int argc, VALUE *argv, VALUE self)
{ {
VALUE which; VALUE which;
VALUE val; VALUE val;
int na;
unsigned long f,fo; unsigned long f,fo;
if(rb_scan_args(argc,argv,"11",&which,&val)==1) val = Qnil; if(rb_scan_args(argc,argv,"11",&which,&val)==1) val = Qnil;
@ -882,9 +881,8 @@ BigDecimal_sqrt(VALUE self, VALUE nFig)
GUARD_OBJ(a,GetVpValue(self,1)); GUARD_OBJ(a,GetVpValue(self,1));
mx = a->Prec *(VpBaseFig() + 1); mx = a->Prec *(VpBaseFig() + 1);
mx *= 2;
n = GetPositiveInt(nFig) + VpBaseFig() + 1; n = GetPositiveInt(nFig) + VpDblFig() + 1;
if(mx <= n) mx = n; if(mx <= n) mx = n;
GUARD_OBJ(c,VpCreateRbObject(mx, "0")); GUARD_OBJ(c,VpCreateRbObject(mx, "0"));
VpSqrt(c, a); VpSqrt(c, a);
@ -1045,7 +1043,6 @@ BigDecimal_to_s(int argc, VALUE *argv, VALUE self)
int fPlus=0; /* =0:default,=1: set ' ' before digits ,set '+' before digits. */ int fPlus=0; /* =0:default,=1: set ' ' before digits ,set '+' before digits. */
Real *vp; Real *vp;
char *psz; char *psz;
char *psz2;
char ch; char ch;
U_LONG nc; U_LONG nc;
S_INT mc = 0; S_INT mc = 0;
@ -1357,7 +1354,7 @@ static int gfCheckVal = 1; /* Value checking flag in VpNmlz() */
#endif /* _DEBUG */ #endif /* _DEBUG */
static U_LONG gnPrecLimit = 0; /* Global upper limit of the precision newly allocated */ static U_LONG gnPrecLimit = 0; /* Global upper limit of the precision newly allocated */
static short gfRoundMode = VP_ROUND_HALF_UP; /* Mode for general rounding operation */ static U_LONG gfRoundMode = VP_ROUND_HALF_UP; /* Mode for general rounding operation */
static U_LONG BASE_FIG = 4; /* =log10(BASE) */ static U_LONG BASE_FIG = 4; /* =log10(BASE) */
static U_LONG BASE = 10000L; /* Base value(value must be 10**BASE_FIG) */ static U_LONG BASE = 10000L; /* Base value(value must be 10**BASE_FIG) */
@ -3257,7 +3254,7 @@ VpToFString(Real *a,char *psz,int fFmt,int fPlus)
e = a->frac[i]; e = a->frac[i];
while(m) { while(m) {
nn = e / m; nn = e / m;
*psz++ = nn + '0'; *psz++ = (char)(nn + '0');
e = e - nn * m; e = e - nn * m;
m /= 10; m /= 10;
} }
@ -3627,14 +3624,22 @@ VpSqrt(Real *y, Real *x)
S_LONG nr; S_LONG nr;
double val; double val;
/* Negative ? */
if(VpGetSign(x) < 0) {
VpSetNaN(y);
return VpException(VP_EXCEPTION_OP,"(VpSqrt) SQRT(negative value)",0);
}
/* NaN or Infinity ? */
if(!VpHasVal(x)) { if(!VpHasVal(x)) {
VpAsgn(y,x,1); VpAsgn(y,x,1);
goto Exit; goto Exit;
} }
if(VpGetSign(x) < 0) { /* One ? */
VpSetNaN(y); if(VpIsOne(x)) {
return VpException(VP_EXCEPTION_OP,"(VpSqrt) SQRT(negative value)",0); VpSetOne(y);
goto Exit;
} }
n = (S_LONG)y->MaxPrec; n = (S_LONG)y->MaxPrec;
@ -3647,17 +3652,11 @@ VpSqrt(Real *y, Real *x)
y_prec = (S_LONG)y->MaxPrec; y_prec = (S_LONG)y->MaxPrec;
f_prec = (S_LONG)f->MaxPrec; f_prec = (S_LONG)f->MaxPrec;
VpAsgn(y, x, 1); /* assign initial guess. y <= x */
prec = x->exponent; prec = x->exponent;
if(prec > 0) ++prec; if(prec > 0) ++prec;
else --prec; else --prec;
prec = prec / 2 - (S_LONG)y->MaxPrec; prec = prec - (S_LONG)y->MaxPrec;
/* VpVtoD(&val, &e, x); /* val <- x */
* y = 0.yyyy yyyy yyyy YYYY
* BASE_FIG = | |
* prec =(0.YYYY*BASE-4)
*/
VpVtoD(&val, &e, y); /* val <- y */
e /= ((S_LONG)BASE_FIG); e /= ((S_LONG)BASE_FIG);
n = e / 2; n = e / 2;
if(e - n * 2 != 0) { if(e - n * 2 != 0) {
@ -3675,13 +3674,13 @@ VpSqrt(Real *y, Real *x)
y->MaxPrec *= 2; y->MaxPrec *= 2;
if(y->MaxPrec > (U_LONG)y_prec) y->MaxPrec = (U_LONG)y_prec; if(y->MaxPrec > (U_LONG)y_prec) y->MaxPrec = (U_LONG)y_prec;
f->MaxPrec = y->MaxPrec; f->MaxPrec = y->MaxPrec;
VpDivd(f, r, x, y); /* f = x/y */ VpDivd(f, r, x, y); /* f = x/y */
VpAddSub(r, y, f, 1); /* r = y + x/y */ VpAddSub(r, f, y, -1); /* r = f - y */
VpMult(f, VpPt5, r); /* f = 0.5*r */ VpMult(f, VpPt5, r); /* f = 0.5*r */
VpAddSub(r, f, y, -1); if(VpIsZero(f)) goto converge;
if(VpIsZero(r)) goto converge; VpAddSub(r, f, y, 1); /* r = y + f */
if(r->exponent <= prec) goto converge; VpAsgn(y, r, 1); /* y = r */
VpAsgn(y, f, 1); if(f->exponent <= prec) goto converge;
} while(++nr < n); } while(++nr < n);
/* */ /* */
#ifdef _DEBUG #ifdef _DEBUG
@ -3691,7 +3690,6 @@ VpSqrt(Real *y, Real *x)
} }
#endif /* _DEBUG */ #endif /* _DEBUG */
y->MaxPrec = y_prec; y->MaxPrec = y_prec;
goto Exit;
converge: converge:
VpChangeSign(y,(S_INT)1); VpChangeSign(y,(S_INT)1);
@ -3765,7 +3763,7 @@ VpMidRound(Real *y, int f, int nf)
case VP_ROUND_HALF_EVEN: /* Banker's rounding */ case VP_ROUND_HALF_EVEN: /* Banker's rounding */
if(v>5) ++div; if(v>5) ++div;
else if(v==5) { else if(v==5) {
if(i==(BASE_FIG-1)) { if((U_LONG)i==(BASE_FIG-1)) {
if(ix && (y->frac[ix-1]%2)) ++div; if(ix && (y->frac[ix-1]%2)) ++div;
} else { } else {
if(div%2) ++div; if(div%2) ++div;