Square Root Madness !
John D. McCalpin
mccalpin at MASIG1.OCEAN.FSU.EDU
Sat Jul 9 03:53:13 AEST 1988
And you thought the exp() function had trouble --- look at what happens
when you give a negative argument to sqrt() while using the floating-point
accelerator ! Probably not what you expected! By the way, this gives
reasonable results without the fpa....
-------------------------------------------------------------------------
program test
#include <fortfpe.h>
call setfpe ( 0, 0 )
do 10 i=-9,9
print *, float(i), sqrt(float(i))
10 continue
end
-------------------------------------------------------------------------
-9.000000 -6.159989
-8.000000 -3.464574
-7.000000 +5.890877
-6.000000 +2.086059E+01
-5.000000 -8.948573
-4.000000 -2.449822
-3.000000 +1.475061E+01
-2.000000 -1.732287
-1.000000 -1.224911
+0.000000E+00 +0.000000E+00
+1.000000 +1.000000
+2.000000 +1.414214
+3.000000 +1.732051
+4.000000 +2.000000
+5.000000 +2.236068
+6.000000 +2.449490
+7.000000 +2.645751
+8.000000 +2.828427
+9.000000 +3.000000
-------------------------------------------------------------------------
John D. McCalpin
mccalpin at nu.cs.fsu.edu
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