#include "blaswrap.h" #include "f2c.h" doublereal dlapy3_(doublereal *x, doublereal *y, doublereal *z__) { /* -- LAPACK auxiliary routine (version 3.1) -- Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd.. November 2006 Purpose ======= DLAPY3 returns sqrt(x**2+y**2+z**2), taking care not to cause unnecessary overflow. Arguments ========= X (input) DOUBLE PRECISION Y (input) DOUBLE PRECISION Z (input) DOUBLE PRECISION X, Y and Z specify the values x, y and z. ===================================================================== */ /* System generated locals */ doublereal ret_val, d__1, d__2, d__3; /* Builtin functions */ double sqrt(doublereal); /* Local variables */ static doublereal w, xabs, yabs, zabs; xabs = abs(*x); yabs = abs(*y); zabs = abs(*z__); /* Computing MAX */ d__1 = max(xabs,yabs); w = max(d__1,zabs); if (w == 0.) { /* W can be zero for max(0,nan,0) adding all three entries together will make sure NaN will not disappear. */ ret_val = xabs + yabs + zabs; } else { /* Computing 2nd power */ d__1 = xabs / w; /* Computing 2nd power */ d__2 = yabs / w; /* Computing 2nd power */ d__3 = zabs / w; ret_val = w * sqrt(d__1 * d__1 + d__2 * d__2 + d__3 * d__3); } return ret_val; /* End of DLAPY3 */ } /* dlapy3_ */