diff --git a/rp-private.h b/rp-private.h
index b4c7dad..0c7193e 100644
--- a/rp-private.h
+++ b/rp-private.h
@@ -36,7 +36,7 @@
#define LONG_SHIFT ((LONG_LENGTH == 16) ? 4 : \
(LONG_LENGTH == 32) ? 5 : \
(LONG_LENGTH == 64) ? 6 : 0)
-#define LONG_MASK (~(-1L<<LONG_SHIFT))
+#define LONG_MASK (~(-(1L<<LONG_SHIFT)))
/* Check if SSE instructions can be used.
We assume that one SSE word of 128 bit is two long's,
diff --git a/sturm.c b/sturm.c
index c78d7c6..5fd2cf5 100644
--- a/sturm.c
+++ b/sturm.c
@@ -27,7 +27,6 @@
***********************************************************************/
#include "ratpoints.h"
-
/**************************************************************************
* Arguments of _ratpoints_compute_sturm() : (from the args argument) *
* *
@@ -53,7 +52,7 @@
/* A helper function: evaluate the polynomial in cofs[] of given degree
at num/2^denexp and return the sign. */
-static long eval_sign(ratpoints_args *args, mpz_t *cofs, long degree,
+static long eval_sign(const ratpoints_args *args, const mpz_t *cofs, long degree,
long num, long denexp)
{
long n, e, s;
@@ -70,11 +69,80 @@ static long eval_sign(ratpoints_args *args, mpz_t *cofs, long degree,
return(s);
}
+static const long max = (long)(((unsigned long)(-1))>>1);
+static const long min = (long)(-(((unsigned long)(-1))>>1));
+ /* recursive helper function */
+static void iterate(long nl, long nr, long del, long der, long cleft, long cright,
+ long sl, long sr, long depth,
+ ratpoints_interval **iptr, const ratpoints_interval *ivlo,
+ const ratpoints_args *args, const long k, const long sturm_degs[],
+ const mpz_t sturm[][args->degree + 1])
+ { /* nl/2^del, nr/2^der : interval left/right endpoints,
+ cleft, cright: sign change counts at endpoints,
+ sl, sr: signs at endpoints,
+ depth: iteration depth */
+ long iter = args->sturm;
+ if(cleft == cright && sl < 0) { return; }
+ /* here we know the polynomial is negative on the interval */
+ if((cleft == cright && sl > 0) || depth >= iter)
+ /* we have to add/extend an interval if we either know that
+ the polynomial is positive on the interval (first condition)
+ or the maximal iteration depth has been reached (second condition) */
+ { double l = ((double)nl)/((double)(1<<del));
+ double u = ((double)nr)/((double)(1<<der));
+ if(*iptr == ivlo)
+ { (*iptr)->low = l; (*iptr)->up = u; (*iptr)++; }
+ else
+ { if(((*iptr)-1)->up == l) /* extend interval */
+ { ((*iptr)-1)->up = u; }
+ else /* new interval */
+ { (*iptr)->low = l; (*iptr)->up = u; (*iptr)++; }
+ }
+ return;
+ }
+ /* now we must split the interval and evaluate the sturm sequence
+ at the midpoint */
+ { long nm, dem, s0, s1, s2, s, cmid = 0, n;
+ if(nl == min)
+ { if(nr == max) { nm = 0; dem = 0; }
+ else { nm = (nr == 0) ? -1 : 2*nr; dem = 0; }
+ }
+ else
+ { if(nr == max) { nm = (nl == 0) ? 1 : 2*nl; dem = 0; }
+ else /* "normal" case */
+ { if(del == der) /* then both are zero */
+ { if(((nl+nr) & 1) == 0) { nm = (nl+nr)>>1; dem = 0; }
+ else { nm = nl+nr; dem = 1; }
+ }
+ else /* here one de* is greater */
+ { if(del > der) { nm = nl + (nr<<(del-der)); dem = del+1; }
+ else { nm = (nl<<(der-del)) + nr; dem = der+1; }
+ }
+ }
+ }
+ s0 = eval_sign(args, sturm[0], sturm_degs[0], nm, dem);
+ s1 = eval_sign(args, sturm[1], sturm_degs[1], nm, dem);
+ if(s0*s1 == -1) { cmid++; }
+ s = (s1 == 0) ? s0 : s1;
+ for(n = 2; n <= k; n++)
+ { s2 = eval_sign(args, sturm[n], sturm_degs[n], nm, dem);
+ if(s2 == -s) { cmid++; s = s2; }
+ else if(s2 != 0) { s = s2; }
+ }
+ /* now recurse */
+ iterate(nl, nm, del, dem, cleft, (s0==0) ? (cmid+1) : cmid,
+ sl, (s0==0) ? -s1 : s0, depth+1,
+ iptr, ivlo, args, k, sturm_degs, sturm);
+ iterate(nm, nr, dem, der, cmid, cright,
+ (s0==0) ? s1 : s0, sr, depth+1,
+ iptr, ivlo, args, k, sturm_degs, sturm);
+ }
+ } /* end iterate() */
+
long _ratpoints_compute_sturm(ratpoints_args *args)
{
mpz_t *cofs = args->cof;
long degree = args->degree;
- long iter = args->sturm;
ratpoints_interval *ivlist = args->domain;
long num_iv = args->num_inter;
long n, m, k, new_num;
@@ -165,75 +233,12 @@ long _ratpoints_compute_sturm(ratpoints_args *args)
/* recall: typedef struct {double low; double up;} ratpoints_interval; */
{ ratpoints_interval ivlocal[1 + (degree>>1)];
ratpoints_interval *iptr = &ivlocal[0];
- long max = (long)(((unsigned long)(-1))>>1);
- long min = -max;
long num_intervals;
long slcf = mpz_cmp_si(cofs[degree], 0);
- /* recursive helper function */
- void iterate(long nl, long nr, long del, long der, long cleft, long cright,
- long sl, long sr, long depth)
- { /* nl/2^del, nr/2^der : interval left/right endpoints,
- cleft, cright: sign change counts at endpoints,
- sl, sr: signs at endpoints,
- depth: iteration depth */
- if(cleft == cright && sl < 0) { return; }
- /* here we know the polynomial is negative on the interval */
- if((cleft == cright && sl > 0) || depth >= iter)
- /* we have to add/extend an interval if we either know that
- the polynomial is positive on the interval (first condition)
- or the maximal iteration depth has been reached (second condition) */
- { double l = ((double)nl)/((double)(1<<del));
- double u = ((double)nr)/((double)(1<<der));
- if(iptr == &ivlocal[0])
- { iptr->low = l; iptr->up = u; iptr++; }
- else
- { if((iptr-1)->up == l) /* extend interval */
- { (iptr-1)->up = u; }
- else /* new interval */
- { iptr->low = l; iptr->up = u; iptr++; }
- }
- return;
- }
- /* now we must split the interval and evaluate the sturm sequence
- at the midpoint */
- { long nm, dem, s0, s1, s2, s, cmid = 0, n;
- if(nl == min)
- { if(nr == max) { nm = 0; dem = 0; }
- else { nm = (nr == 0) ? -1 : 2*nr; dem = 0; }
- }
- else
- { if(nr == max) { nm = (nl == 0) ? 1 : 2*nl; dem = 0; }
- else /* "normal" case */
- { if(del == der) /* then both are zero */
- { if(((nl+nr) & 1) == 0) { nm = (nl+nr)>>1; dem = 0; }
- else { nm = nl+nr; dem = 1; }
- }
- else /* here one de* is greater */
- { if(del > der) { nm = nl + (nr<<(del-der)); dem = del+1; }
- else { nm = (nl<<(der-del)) + nr; dem = der+1; }
- }
- }
- }
- s0 = eval_sign(args, sturm[0], sturm_degs[0], nm, dem);
- s1 = eval_sign(args, sturm[1], sturm_degs[1], nm, dem);
- if(s0*s1 == -1) { cmid++; }
- s = (s1 == 0) ? s0 : s1;
- for(n = 2; n <= k; n++)
- { s2 = eval_sign(args, sturm[n], sturm_degs[n], nm, dem);
- if(s2 == -s) { cmid++; s = s2; }
- else if(s2 != 0) { s = s2; }
- }
- /* now recurse */
- iterate(nl, nm, del, dem, cleft, (s0==0) ? (cmid+1) : cmid,
- sl, (s0==0) ? -s1 : s0, depth+1);
- iterate(nm, nr, dem, der, cmid, cright,
- (s0==0) ? s1 : s0, sr, depth+1);
- }
- } /* end iterate() */
-
iterate(min, max, 0, 0, count2, count1,
- (degree & 1) ? -slcf : slcf, slcf, 0);
+ (degree & 1) ? -slcf : slcf, slcf, 0,
+ &iptr, &ivlocal[0], args, k, sturm_degs, sturm);
num_intervals = iptr - &ivlocal[0];
/* intersect with given intervals */
{ ratpoints_interval local_copy[num_iv];
