GNU Octave  4.2.1 A high-level interpreted language, primarily intended for numerical computations, mostly compatible with Matlab
zuchk.f
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1  SUBROUTINE zuchk(YR, YI, NZ, ASCLE, TOL)
2 C***BEGIN PROLOGUE ZUCHK
3 C***REFER TO ZSERI,ZUOIK,ZUNK1,ZUNK2,ZUNI1,ZUNI2,ZKSCL
4 C
5 C Y ENTERS AS A SCALED QUANTITY WHOSE MAGNITUDE IS GREATER THAN
6 C EXP(-ALIM)=ASCLE=1.0E+3*D1MACH(1)/TOL. THE TEST IS MADE TO SEE
7 C IF THE MAGNITUDE OF THE REAL OR IMAGINARY PART WOULD UNDERFLOW
8 C WHEN Y IS SCALED (BY TOL) TO ITS PROPER VALUE. Y IS ACCEPTED
9 C IF THE UNDERFLOW IS AT LEAST ONE PRECISION BELOW THE MAGNITUDE
10 C OF THE LARGEST COMPONENT; OTHERWISE THE PHASE ANGLE DOES NOT HAVE
11 C ABSOLUTE ACCURACY AND AN UNDERFLOW IS ASSUMED.
12 C
13 C***ROUTINES CALLED (NONE)
14 C***END PROLOGUE ZUCHK
15 C
16 C COMPLEX Y
17  DOUBLE PRECISION ASCLE, SS, ST, TOL, WR, WI, YR, YI
18  INTEGER NZ
19  nz = 0
20  wr = dabs(yr)
21  wi = dabs(yi)
22  st = dmin1(wr,wi)
23  IF (st.GT.ascle) RETURN
24  ss = dmax1(wr,wi)
25  st = st/tol
26  IF (ss.LT.st) nz = 1
27  RETURN
28  END
subroutine zuchk(YR, YI, NZ, ASCLE, TOL)
Definition: zuchk.f:1