[src/cbrt.c] Description of the algorithm: corrected indentation;

renamed variable r to t in order to avoid confusion with the code
(where r has a different meaning).

git-svn-id: svn://scm.gforge.inria.fr/svn/mpfr/trunk@13769 280ebfd0-de03-0410-8827-d642c229c3f4

1 files changed, 15 insertions, 15 deletions

diff --git a/src/cbrt.c b/src/cbrt.c
index f327a2dea..58a35681a 100644
--- a/src/cbrt.c
+++ b/src/cbrt.c
@@ -23,26 +23,26 @@ https://www.gnu.org/licenses/ or write to the Free Software Foundation, Inc.,
 #define MPFR_NEED_LONGLONG_H
 #include "mpfr-impl.h"
 
- /* The computation of y = x^(1/3) is done as follows:
+/* The computation of y = x^(1/3) is done as follows:
 
-    Let x = sign * m * 2^(3*e) where m is an integer >= 2^(3n-3) with
-    n = PREC(y), i.e. m has at least 3n-2 bits.
+   Let x = sign * m * 2^(3*e) where m is an integer >= 2^(3n-3) with
+   n = PREC(y), i.e. m has at least 3n-2 bits.
 
-    Let s be the integer cube root of m, i.e. the maximum integer such that
-    m = s^3 + r with r >= 0.
+   Let s be the integer cube root of m, i.e. the maximum integer such that
+   m = s^3 + t with t >= 0.
 
-    The constraint m >= 2^(3n-3) allows one to have sufficient precision
-    for s: s >= 2^(n-1), i.e. s has at least n bits.
+   The constraint m >= 2^(3n-3) allows one to have sufficient precision
+   for s: s >= 2^(n-1), i.e. s has at least n bits.
 
-    FIXME: The description below is incorrect if s has more than n bits
-    (since n is the target precision).
+   FIXME: The description below is incorrect if s has more than n bits
+   (since n is the target precision).
 
-    Then x^(1/3) = s * 2^e if r=0
-         x^(1/3) = (s+1) * 2^e if round up
-         x^(1/3) = (s-1) * 2^e if round down
-         x^(1/3) = s * 2^e if nearest and r < 3/2*s^2+3/4*s+1/8
-                   (s+1) * 2^e otherwise
- */
+   Then x^(1/3) = s * 2^e if t = 0
+        x^(1/3) = (s+1) * 2^e if round up
+        x^(1/3) = (s-1) * 2^e if round down
+        x^(1/3) = s * 2^e if nearest and t < 3/2*s^2+3/4*s+1/8
+                  (s+1) * 2^e otherwise
+*/
 
 int
 mpfr_cbrt (mpfr_ptr y, mpfr_srcptr x, mpfr_rnd_t rnd_mode)