add M_SQRT1_2 (1/sqrt(2))

diff --git a/include/mathconst.h b/include/mathconst.h
index ee11bcc3055118bf6d2b888f181d3f320ba96181..56fef8cdf9dbc991be3bbff2b8342d0924446f5d 100755 (executable)
--- a/include/mathconst.h
+++ b/include/mathconst.h
@@ -25,5 +25,6 @@
 #define        M_SQRT2         1.41421356237309504880168872420969808
 #define        M_1_SQRT2       0.70710678118654752440084436210484904
 #define        M_EULER         0.57721566490153286060651209008240243
+#define        M_SQRT1_2       0.70710678118654752440084436210484904
 
 #endif /* _MATHCONST_H */