[bug-gawk] GAWK 4.1 SQRT() bug

[Katherine Wasserman]

In version 4.1.60 of GAWK the sqrt() function does not work correctly on 
bignums.
Here's a demo of the problem along with, a function that does work correctly.

Running this program (sqrt-bug.awk):
--------------------------------------------------------------------
BEGIN {
a=11111111111111111111111111111111111111111111111111111111111
print sqrt(a^2)
print sq_root(a^2)
}


function sq_root(x, temp,r,z)
{  temp=substr(x,1,length(x)/2) + 0 # a good first guess
   z=0
   while (abs(z-temp)>1)
    { z=temp
      div(x,temp,r)
      temp=r["quotient"] + temp
      div(temp,2,r)
      temp=r["quotient"]
    }
   return temp
}

function abs(x)
{ return (x<0 ? -x : x)
}

--------------------------------------------------------------------
gawk -M -f sqrt-bug.awk

results in:
11111111111111111261130863809439559987542611609749437808640
11111111111111111111111111111111111111111111111111111111111

Thanks,
Katie