* angle and scm_flo0
@ 2003-07-17 23:45 Kevin Ryde
0 siblings, 0 replies; only message in thread
From: Kevin Ryde @ 2003-07-17 23:45 UTC (permalink / raw)
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To save a bit of consing and calls to atan2,
* numbers.c (scm_angle): Use scm_flo0 for non-negative inum, bignum
and real.
I guess the same can be done for negatives, returning pi. Would
scm_sys_protects be the right place to add an scm_flo_pi? I see
abs_most_negative_fixnum uses scm_permanent_object instead.
For the actual pi value, I guess there'd be a choice between M_PI and
the return from atan2(0.0,-1.0). The two ought to be the same of
course. Maybe use the constant and have one of the tests see that
atan2 agrees.
[-- Attachment #2: numbers.c.angle-flo0.diff --]
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--- numbers.c.~1.193.~ 2003-07-08 10:28:38.000000000 +1000
+++ numbers.c 2003-07-17 10:10:52.000000000 +1000
@@ -3947,7 +3947,7 @@
{
if (SCM_INUMP (z)) {
if (SCM_INUM (z) >= 0) {
- return scm_make_real (atan2 (0.0, 1.0));
+ return scm_flo0;
} else {
return scm_make_real (atan2 (0.0, -1.0));
}
@@ -3957,10 +3957,13 @@
if (sgn < 0) {
return scm_make_real (atan2 (0.0, -1.0));
} else {
- return scm_make_real (atan2 (0.0, 1.0));
+ return scm_flo0;
}
} else if (SCM_REALP (z)) {
- return scm_make_real (atan2 (0.0, SCM_REAL_VALUE (z)));
+ if (SCM_REAL_VALUE (z) >= 0)
+ return scm_flo0;
+ else
+ return scm_make_real (atan2 (0.0, -1.0));
} else if (SCM_COMPLEXP (z)) {
return scm_make_real (atan2 (SCM_COMPLEX_IMAG (z), SCM_COMPLEX_REAL (z)));
} else {
[-- Attachment #3: angle.test --]
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(with-test-prefix "angle"
(define pi 3.14159265358979323846)
(define (almost= x y)
(> 0.01 (magnitude (- x y))))
(pass-if "inum +ve" (= 0 (angle 1)))
(pass-if "inum -ve" (almost= pi (angle -1)))
(pass-if "bignum +ve" (= 0 (angle (1+ fixnum-max))))
(pass-if "bignum -ve" (almost= pi (angle (1- fixnum-min))))
(pass-if "flonum +ve" (= 0 (angle 1.5)))
(pass-if "flonum -ve" (almost= pi (angle -1.5))))
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