>From http://en.cppreference.com/w/c/numeric/complex/csqrt :
csqrt(conj(z)) == conj(csqrt(z))
Before patch
csqrt(-4.0 + -0.0i) = 0.0 + 2.0j
but should be
csqrt(-4.0 + -0.0i) = 0.0 - 2.0j
--
Alexandr Shadchin
Index: lib/libm/src/s_csqrt.c
===================================================================
RCS file: /cvs/src/lib/libm/src/s_csqrt.c,v
retrieving revision 1.6
diff -u -p -r1.6 s_csqrt.c
--- lib/libm/src/s_csqrt.c 3 Jul 2013 04:46:36 -0000 1.6
+++ lib/libm/src/s_csqrt.c 24 Nov 2015 08:45:25 -0000
@@ -79,7 +79,7 @@ csqrt(double complex z)
r = fabs (x);
r = sqrt (r);
if (x < 0.0) {
- w = 0.0 + r * I;
+ w = 0.0 + copysign(r, y) * I;
}
else {
w = r + y * I;
Index: lib/libm/src/s_csqrtf.c
===================================================================
RCS file: /cvs/src/lib/libm/src/s_csqrtf.c,v
retrieving revision 1.2
diff -u -p -r1.2 s_csqrtf.c
--- lib/libm/src/s_csqrtf.c 18 Jul 2010 18:42:26 -0000 1.2
+++ lib/libm/src/s_csqrtf.c 24 Nov 2015 08:45:25 -0000
@@ -72,7 +72,7 @@ csqrtf(float complex z)
if(y == 0.0f) {
if (x < 0.0f) {
- w = 0.0f + sqrtf(-x) * I;
+ w = 0.0f + copysign(sqrtf(-x), y) * I;
return (w);
}
else if (x == 0.0f) {
Index: lib/libm/src/s_csqrtl.c
===================================================================
RCS file: /cvs/src/lib/libm/src/s_csqrtl.c,v
retrieving revision 1.2
diff -u -p -r1.2 s_csqrtl.c
--- lib/libm/src/s_csqrtl.c 20 Jul 2011 19:28:33 -0000 1.2
+++ lib/libm/src/s_csqrtl.c 24 Nov 2015 08:45:25 -0000
@@ -72,7 +72,7 @@ csqrtl(long double complex z)
if (y == 0.0L) {
if (x < 0.0L) {
- w = 0.0L + sqrtl(-x) * I;
+ w = 0.0L + copysign(sqrtl(-x), y) * I;
return (w);
}
else {
