Patch by Nadav Horesh to make acosh and asinh better.
Tim posted a long comment to python-dev (subject: "Controversial patch
(cmath)"; date: 6/29/00). The conclusion is that this whole module
stinks and this patch isn't perfect, but it's better than the acosh
and asinh we had, so let's check it in.
diff --git a/Modules/cmathmodule.c b/Modules/cmathmodule.c
index ab8b5e1..313827b 100644
--- a/Modules/cmathmodule.c
+++ b/Modules/cmathmodule.c
@@ -57,8 +57,11 @@
static Py_complex c_acosh(x)
Py_complex x;
{
- return c_log(c_sum(x,c_prod(c_i,
- c_sqrt(c_diff(c_1,c_prod(x,x))))));
+ Py_complex z;
+ z = c_sqrt(c_half);
+ z = c_log(c_prod(z, c_sum(c_sqrt(c_sum(x,c_1)),
+ c_sqrt(c_diff(x,c_1)))));
+ return c_sum(z, z);
}
static char c_acosh_doc [] =
@@ -70,8 +73,11 @@
static Py_complex c_asin(x)
Py_complex x;
{
- return c_neg(c_prodi(c_log(c_sum(c_prod(c_i,x),
- c_sqrt(c_diff(c_1,c_prod(x,x)))))));
+ Py_complex z;
+ z = c_sqrt(c_half);
+ z = c_log(c_prod(z, c_sum(c_sqrt(c_sum(x,c_i)),
+ c_sqrt(c_diff(x,c_i)))));
+ return c_sum(z, z);
}
static char c_asin_doc [] =
@@ -85,9 +91,8 @@
{
/* Break up long expression for WATCOM */
Py_complex z;
- z = c_sum(c_1,c_prod(x,x));
- z = c_diff(c_sqrt(z),x);
- return c_neg(c_log(z));
+ z = c_sum(c_1,c_prod(x, x));
+ return c_log(c_sum(c_sqrt(z), x));
}
static char c_asinh_doc [] =