DLAPY2(3) returns sqrt(x**2+y**2), taking care not to cause unnecessary overflow

SYNOPSIS

DOUBLE PRECISION
FUNCTION DLAPY2( X, Y )

    
DOUBLE PRECISION X, Y

PURPOSE

DLAPY2 returns sqrt(x**2+y**2), taking care not to cause unnecessary overflow.

ARGUMENTS

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