On Wednesday 24 May 2006 01:42 am, [EMAIL PROTECTED] wrote:
> Hello
>
> Instead of computing 2 times fabs(fn), why not storing it in a
> variable ?
>
> result->val = fn;
> - result->err = GSL_DBL_EPSILON*fabs(fn);
> + result->err = 2.0*GSL_DBL_EPSILON;
> + double factor = fabs(fn);
> + if (factor > 1.0)
> + result->err *= factor;
>
> Have a nice day.
Sure, that sounds fine to me. The cost of the extra fabs() is rather
trivial, but avoiding it will save a few clock cycles.
I've attached a patch to be used in place of the earlier patch.
Thanks.
Lowell
--
Lowell D. Johnson
Linux: Bringing stability, security, and freedom to home and business
computing since 1991. www.linux.org
Free and Open Source Software: Of the people, by the people, for the
people.
Index: mathieu_angfunc.c
===================================================================
RCS file: /cvs/gsl/gsl/specfunc/mathieu_angfunc.c,v
retrieving revision 1.1
diff -u -r1.1 mathieu_angfunc.c
--- mathieu_angfunc.c 18 Apr 2006 17:59:46 -0000 1.1
+++ mathieu_angfunc.c 24 May 2006 22:17:49 -0000
@@ -31,7 +31,7 @@
int gsl_sf_mathieu_c(int order, double qq, double zz, gsl_sf_result *result)
{
int even_odd, ii, status;
- double coeff[NUM_MATHIEU_COEFF], aa, norm, fn;
+ double coeff[NUM_MATHIEU_COEFF], aa, norm, fn, factor;
norm = 0.0;
@@ -54,7 +54,10 @@
fn = cos(order*zz)/norm;
result->val = fn;
- result->err = GSL_DBL_EPSILON*fabs(fn);
+ result->err = 2.0*GSL_DBL_EPSILON;
+ factor = fabs(fn);
+ if (factor > 1.0)
+ result->err *= factor;
return GSL_SUCCESS;
}
@@ -97,7 +100,10 @@
fn /= norm;
result->val = fn;
- result->err = GSL_DBL_EPSILON*fabs(fn);
+ result->err = 2.0*GSL_DBL_EPSILON;
+ factor = fabs(fn);
+ if (factor > 1.0)
+ result->err *= factor;
return GSL_SUCCESS;
}
@@ -106,7 +112,7 @@
int gsl_sf_mathieu_s(int order, double qq, double zz,gsl_sf_result *result)
{
int even_odd, ii, status;
- double coeff[NUM_MATHIEU_COEFF], aa, norm, fn;
+ double coeff[NUM_MATHIEU_COEFF], aa, norm, fn, factor;
norm = 0.0;
@@ -126,7 +132,10 @@
fn = sin(order*zz);
result->val = fn;
- result->err = GSL_DBL_EPSILON*fabs(fn);
+ result->err = 2.0*GSL_DBL_EPSILON;
+ factor = fabs(fn);
+ if (factor > 1.0)
+ result->err *= factor;
return GSL_SUCCESS;
}
@@ -167,7 +176,10 @@
fn /= norm;
result->val = fn;
- result->err = GSL_DBL_EPSILON*fabs(fn);
+ result->err = 2.0*GSL_DBL_EPSILON;
+ factor = fabs(fn);
+ if (factor > 1.0)
+ result->err *= factor;
return GSL_SUCCESS;
}
Index: mathieu_radfunc.c
===================================================================
RCS file: /cvs/gsl/gsl/specfunc/mathieu_radfunc.c,v
retrieving revision 1.1
diff -u -r1.1 mathieu_radfunc.c
--- mathieu_radfunc.c 18 Apr 2006 17:59:46 -0000 1.1
+++ mathieu_radfunc.c 24 May 2006 22:17:49 -0000
@@ -34,7 +34,7 @@
gsl_sf_result *result)
{
int even_odd, kk, mm, status;
- double maxerr = 1e-14, amax, pi = acos(-1.0), fn;
+ double maxerr = 1e-14, amax, pi = acos(-1.0), fn, factor;
double coeff[NUM_MATHIEU_COEFF], aa, fc, fj, fjp;
double j1c, j2c, j1pc, j2pc;
double u1, u2;
@@ -141,7 +141,10 @@
}
result->val = fn;
- result->err = GSL_DBL_EPSILON*fabs(fn);
+ result->err = 2.0*GSL_DBL_EPSILON;
+ factor = fabs(fn);
+ if (factor > 1.0)
+ result->err *= factor;
return GSL_SUCCESS;
}
@@ -151,7 +154,7 @@
gsl_sf_result *result)
{
int even_odd, kk, mm, status;
- double maxerr = 1e-14, amax, pi = acos(-1.0), fn;
+ double maxerr = 1e-14, amax, pi = acos(-1.0), fn, factor;
double coeff[NUM_MATHIEU_COEFF], aa, fc, fj, fjp, fjm;
double j1c, j2c, j1mc, j2mc, j1pc, j2pc;
double u1, u2;
@@ -268,7 +271,10 @@
}
result->val = fn;
- result->err = GSL_DBL_EPSILON*fabs(fn);
+ result->err = 2.0*GSL_DBL_EPSILON;
+ factor = fabs(fn);
+ if (factor > 1.0)
+ result->err *= factor;
return GSL_SUCCESS;
}
