SLAPY2(3) returns sqrt(x**2+y**2), taking care not to cause unnecessary overflow

SYNOPSIS

REAL FUNCTION
SLAPY2( X, Y )

    
REAL X, Y

PURPOSE

SLAPY2 returns sqrt(x**2+y**2), taking care not to cause unnecessary overflow.

ARGUMENTS

X (input) REAL
Y (input) REAL X and Y specify the values x and y.