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authorGuido van Rossum <guido@python.org>2000-06-30 02:29:22 +0000
committerGuido van Rossum <guido@python.org>2000-06-30 02:29:22 +0000
commitf385c5e544bd7e13c6c6714e85828292d6de8b8e (patch)
tree9005e425c82cedd34d11eef1f75e0e7feea18ca4 /Modules/cmathmodule.c
parent730067effc4347809f66add6af3c63bc46be9dd9 (diff)
downloadcpython-git-f385c5e544bd7e13c6c6714e85828292d6de8b8e.tar.gz
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.
Diffstat (limited to 'Modules/cmathmodule.c')
-rw-r--r--Modules/cmathmodule.c19
1 files changed, 12 insertions, 7 deletions
diff --git a/Modules/cmathmodule.c b/Modules/cmathmodule.c
index ab8b5e1271..313827b211 100644
--- a/Modules/cmathmodule.c
+++ b/Modules/cmathmodule.c
@@ -57,8 +57,11 @@ Return the arc cosine of x.";
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 @@ Return the hyperbolic arccosine of x.";
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 @@ static Py_complex c_asinh(x)
{
/* 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 [] =