math: doc
R=r
DELTA=173 (74 added, 14 deleted, 85 changed)
OCL=25753
CL=25767
diff --git a/src/lib/math/sqrt.go b/src/lib/math/sqrt.go
index 466b927..79384f6 100644
--- a/src/lib/math/sqrt.go
+++ b/src/lib/math/sqrt.go
@@ -13,29 +13,35 @@
* calls frexp
*/
-func Sqrt(arg float64) float64 {
- if IsInf(arg, 1) {
- return arg;
+// Sqrt returns the square root of x.
+//
+// Special cases are:
+// Sqrt(+Inf) = +Inf
+// Sqrt(0) = 0
+// Sqrt(x < 0) = NaN
+func Sqrt(x float64) float64 {
+ if IsInf(x, 1) {
+ return x;
}
- if arg <= 0 {
- if arg < 0 {
+ if x <= 0 {
+ if x < 0 {
return NaN();
}
return 0;
}
- x,exp := Frexp(arg);
- for x < 0.5 {
- x = x*2;
+ y, exp := Frexp(x);
+ for y < 0.5 {
+ y = y*2;
exp = exp-1;
}
if exp&1 != 0 {
- x = x*2;
+ y = y*2;
exp = exp-1;
}
- temp := 0.5 * (1+x);
+ temp := 0.5 * (1+y);
for exp > 60 {
temp = temp * float64(1<<30);
@@ -54,7 +60,7 @@
}
for i:=0; i<=4; i++ {
- temp = 0.5*(temp + arg/temp);
+ temp = 0.5*(temp + x/temp);
}
return temp;
}
