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authorTaru Karttunen <taruti@taruti.net>2011-03-30 15:46:40 +0300
committerTaru Karttunen <taruti@taruti.net>2011-03-30 15:46:40 +0300
commite5888a1ffdae813d7575f5fb02275c6bb07e5199 (patch)
treed8d51eac403f07814b9e936eed0c9a79195e2450 /sys/src/libc/port/sinh.c
Import sources from 2011-03-30 iso image
Diffstat (limited to 'sys/src/libc/port/sinh.c')
-rwxr-xr-xsys/src/libc/port/sinh.c62
1 files changed, 62 insertions, 0 deletions
diff --git a/sys/src/libc/port/sinh.c b/sys/src/libc/port/sinh.c
new file mode 100755
index 000000000..115d42c0e
--- /dev/null
+++ b/sys/src/libc/port/sinh.c
@@ -0,0 +1,62 @@
+#include <u.h>
+#include <libc.h>
+
+/*
+ * sinh(arg) returns the hyperbolic sine of its floating-
+ * point argument.
+ *
+ * The exponential function is called for arguments
+ * greater in magnitude than 0.5.
+ *
+ * A series is used for arguments smaller in magnitude than 0.5.
+ * The coefficients are #2029 from Hart & Cheney. (20.36D)
+ *
+ * cosh(arg) is computed from the exponential function for
+ * all arguments.
+ */
+
+static double p0 = -0.6307673640497716991184787251e+6;
+static double p1 = -0.8991272022039509355398013511e+5;
+static double p2 = -0.2894211355989563807284660366e+4;
+static double p3 = -0.2630563213397497062819489e+2;
+static double q0 = -0.6307673640497716991212077277e+6;
+static double q1 = 0.1521517378790019070696485176e+5;
+static double q2 = -0.173678953558233699533450911e+3;
+
+double
+sinh(double arg)
+{
+ double temp, argsq;
+ int sign;
+
+ sign = 0;
+ if(arg < 0) {
+ arg = -arg;
+ sign++;
+ }
+ if(arg > 21) {
+ temp = exp(arg)/2;
+ goto out;
+ }
+ if(arg > 0.5) {
+ temp = (exp(arg) - exp(-arg))/2;
+ goto out;
+ }
+ argsq = arg*arg;
+ temp = (((p3*argsq+p2)*argsq+p1)*argsq+p0)*arg;
+ temp /= (((argsq+q2)*argsq+q1)*argsq+q0);
+out:
+ if(sign)
+ temp = -temp;
+ return temp;
+}
+
+double
+cosh(double arg)
+{
+ if(arg < 0)
+ arg = - arg;
+ if(arg > 21)
+ return exp(arg)/2;
+ return (exp(arg) + exp(-arg))/2;
+}