Help on the function

[Henry]

The following c code was a conversion from Fortran. I am not a fluent
C programmer. I do not know if the code section in comments "CAN THE
FOLLOWING CODE EVER BE CALLED ? */" is really called.

Any help is appreciated. Thanks

---------------------------------------------------------------------

static void E0001(int IENTRY,int *status,double *x,double *fx,
double *xlo,double *xhi,unsigned long *qleft,
unsigned long *qhi,double *zabstl,double *zreltl,
double *zxhi,double *zxlo)
{
#define ftol(zx) (0.5e0*fifdmax1 (abstol,reltol* fabs((zx))))
static double a,abstol,b,c,d, fa,fb,fc,fd,fda ,fdb,m,mb,p,q,r eltol,tol,w,xxh i,xxlo;
static int ext,i99999;
static unsigned long first,qrzero;
switch(IENTRY){ case 0: goto DZROR; case 1: goto DSTZR;}
DZROR:
if(*status > 0) goto S280;
*xlo = xxlo;
*xhi = xxhi;
b = *x = *xlo;

i99999 = 1;
goto S270;
/* CAN THE FOLLOWING CODE EVER BE CALLED ? */
S10:
fb = *fx;
*xlo = *xhi;
a = *x = *xlo;
i99999 = 2;
goto S270;
S20:
if(!(fb < 0.0e0)) goto S40;
if(!(*fx < 0.0e0)) goto S30;
*status = -1;
*qleft = *fx < fb;
*qhi = 0;
return;
S40:
S30:
if(!(fb > 0.0e0)) goto S60;
if(!(*fx > 0.0e0)) goto S50;
*status = -1;
*qleft = *fx > fb;
*qhi = 1;
return;
S60:
S50:
fa = *fx;
first = 1;
S70:
c = a;
fc = fa;
ext = 0;
S80:
if(!(fabs(fc) < fabs(fb))) goto S100;
if(!(c != a)) goto S90;
d = a;
fd = fa;
S90:
a = b;
fa = fb;
*xlo = c;
b = *xlo;
fb = fc;
c = a;
fc = fa;
S100:
tol = ftol(*xlo);
m = (c+b)*.5e0;
mb = m-b;
if(!(fabs(mb) > tol)) goto S240;
if(!(ext > 3)) goto S110;
w = mb;
goto S190;
S110:
tol = fifdsign(tol,mb );
p = (b-a)*fb;
if(!first) goto S120;
q = fa-fb;
first = 0;
goto S130;
S120:
fdb = (fd-fb)/(d-b);
fda = (fd-fa)/(d-a);
p = fda*p;
q = fdb*fa-fda*fb;
S130:
if(!(p < 0.0e0)) goto S140;
p = -p;
q = -q;
S140:
if(ext == 3) p *= 2.0e0;
if(!(p*1.0e0 == 0.0e0 || p <= q*tol)) goto S150;
w = tol;
goto S180;
S150:
if(!(p < mb*q)) goto S160;
w = p/q;
goto S170;
S160:
w = mb;
S190:
S180:
S170:
d = a;
fd = fa;
a = b;
fa = fb;
b += w;
*xlo = b;
*x = *xlo;
i99999 = 3;
goto S270;
S200:
fb = *fx;
if(!(fc*fb >= 0.0e0)) goto S210;
goto S70;
S210:
if(!(w == mb)) goto S220;
ext = 0;
goto S230;
S220:
ext += 1;
S230:
goto S80;
S240:
*xhi = c;
qrzero = fc >= 0.0e0 && fb <= 0.0e0 || fc < 0.0e0 && fb >= 0.0e0;
if(!qrzero) goto S250;
*status = 0;
goto S260;
S250:
*status = -1;
S260:
return;
/* END OF CAN THE ABOVE CODES BE CALLED? */


DSTZR:
xxlo = *zxlo;
xxhi = *zxhi;
abstol = *zabstl;
reltol = *zreltl;
return;
S270:
*status = 1;
return;
S280:
switch((int)i99 999){case 1: goto S10;case 2: goto S20;case 3: goto
S200;
default: break;}
#undef ftol
}

[Martin Ambuhl]

Re: Help on the function

Henry wrote:[color=blue]
> The following c code was a conversion from Fortran. I am not a fluent
> C programmer. I do not know if the code section in comments "CAN THE
> FOLLOWING CODE EVER BE CALLED ? */" is really called.[/color]

[...][color=blue]
> goto S270;
> /* CAN THE FOLLOWING CODE EVER BE CALLED ? */
> S10:[/color]
[...][color=blue]
> S280:
> switch((int)i99 999){case 1: goto S10;case 2: goto S20;case 3: goto
> S200;
> default: break;}[/color]

If you can get to S280 with i99999==1, then you can get to S10