diff --git a/fvn_fnlib/z0lgmc.f b/fvn_fnlib/z0lgmc.f
index 4f0a394..a67e108 100644
--- a/fvn_fnlib/z0lgmc.f
+++ b/fvn_fnlib/z0lgmc.f
@@ -1,4 +1,4 @@
-      complex(8) function z0lgmc (z)
+      complex(kind(1.d0)) function z0lgmc (z)
       implicit none
 c august 1980 edition.  w. fullerton c3, los alamos scientific lab.
 c
@@ -8,8 +8,8 @@ c     (z+0.5)*clog(1+1/z) - 1 = (z+0.5)*(clog(1+q) - q + q*q/2) - q*q/4
 c        = (z+0.5)*q**3*c9ln2r(q) - q**2/4,
 c where  c9ln2r  is (clog(1+q) - q + 0.5*q**2) / q**3.
 c
-      complex(8) z, q, z9ln2r
-      real(8) zabsz
+      complex(kind(1.d0)) z, q, z9ln2r
+      real(kind(1.d0)) zabsz
 
       external z9ln2r
 c
diff --git a/fvn_fnlib/z8lgmc.f b/fvn_fnlib/z8lgmc.f
index f8dbdfd..d429145 100644
--- a/fvn_fnlib/z8lgmc.f
+++ b/fvn_fnlib/z8lgmc.f
@@ -1,4 +1,4 @@
-      complex(8) function z8lgmc (zin)
+      complex(kind(1.d0)) function z8lgmc (zin)
       implicit none
 c may 1978 edition.  w. fullerton, c3, los alamos scientific lab.
 c
@@ -9,9 +9,10 @@ c is small.
 c when real(z) is negative, c8lgmc merely returns a correction which
 c may be wrong by a multiple of 2*pi*i.
 c
-      complex(8) zin, z, corr,  z9lgmc, z0lgmc, zexp, zlnrel
-      real(8) d1mach,pi,bound,sqeps,eps,x,y,absz,test
+      complex(kind(1.d0)) zin, z, corr,  z9lgmc, z0lgmc, zexp, zlnrel
+      real(kind(1.d0)) d1mach,pi,bound,sqeps,eps,x,y,absz,test
       integer nterm,n,i,irold,ir
+c      complex(kind(1.d0)) tmp_arg
       external  z0lgmc, z9lgmc, zlnrel,
      1  d1mach
       data pi / 3.1415926535 8979324d0 /
@@ -55,7 +56,9 @@ c
 c
       z = zin
       if (y.lt.0.0) z = conjg(z)
-      corr = -dcmplx(0.0,pi) + zlnrel(-exp(dcmplx(0.,2.*pi)*z))
+c      tmp_arg = -exp(cmplx(0.,2.*pi,kind(1.d0))*z)
+      corr = -cmplx(0.0,pi,kind(1.d0)) + 
+     1 zlnrel(-exp(cmplx(0.,2.*pi,kind(1.d0))*z))
       if (y.lt.0.0) corr = conjg(corr)
 c
       z8lgmc = corr - z8lgmc
diff --git a/fvn_fnlib/z9lgmc.f b/fvn_fnlib/z9lgmc.f
index 2a6ac58..608a76f 100644
--- a/fvn_fnlib/z9lgmc.f
+++ b/fvn_fnlib/z9lgmc.f
@@ -1,4 +1,4 @@
-      complex(8) function z9lgmc (zin)
+      complex(kind(1.d0)) function z9lgmc (zin)
       implicit none
 c april 1978 edition.  w. fullerton c3, los alamos scientific lab.
 c
@@ -7,8 +7,8 @@ c .ge. 0.0 and for large abs(aimag(y)) when real(z) .lt. 0.0.  we find
 c c9lgmc so that
 c   clog(cgamma(z)) = 0.5*alog(2.*pi) + (z-0.5)*clog(z) - z + c9lgmc(z).
 c
-      complex(8) zin, z, z2inv
-      real(8) d1mach,bern,xbig,xmax,bound,cabsz,x,y
+      complex(kind(1.d0)) zin, z, z2inv
+      real(kind(1.d0)) d1mach,bern,xbig,xmax,bound,cabsz,x,y
       integer nterm,i,ndx
       external d1mach
 c
diff --git a/fvn_fnlib/z9ln2r.f b/fvn_fnlib/z9ln2r.f
index 9521022..ed94a00 100644
--- a/fvn_fnlib/z9ln2r.f
+++ b/fvn_fnlib/z9ln2r.f
@@ -1,4 +1,4 @@
-      complex(8) function z9ln2r (z)
+      complex(kind(1.d0)) function z9ln2r (z)
       implicit none
 c april 1978 edition.  w. fullerton c3, los alamos scientific lab.
 c
@@ -27,8 +27,9 @@ c     c9ln2r(z) = (xz-i*yz)**3 * (-xz - cabs(z)/4
 c        + 0.5*(2*xz+cabs(z))**3 * r9ln2r(2*x+cabs(z)**2)
 c        + i*yz/(1+x) * (xz**2 + (yz/(1+x))**2*r9atn1(y/(1+x)) ))
 c
-      complex(8) z
-      real(8) x,y,xz,yz,cabsz,d9ln2r,d9atn1,arg,rpart,aipart,y1x
+      complex(kind(1.d0)) z
+      real(kind(1.d0)) x,y,xz,yz,cabsz,d9ln2r,d9atn1,arg,rpart,aipart,
+     1 y1x
       
       external d9atn1, d9ln2r
 c
@@ -38,7 +39,7 @@ c
       cabsz = abs(z)
       if (cabsz.gt.0.8125) go to 20
 c
-      z9ln2r = dcmplx (1.0/3.0, 0.0)
+      z9ln2r = cmplx (1.0/3.0, 0.0, kind(1.d0))
       if (cabsz.eq.0.0) return
 c
       xz = x/cabsz
@@ -49,7 +50,8 @@ c
       y1x = yz/(1.0+x)
       aipart = y1x * (xz**2 + y1x**2*d9atn1(cabsz*y1x) )
 c
-      z9ln2r = dcmplx(xz,-yz)**3 * dcmplx(rpart,aipart)
+      z9ln2r = cmplx(xz,-yz,kind(1.d0))**3 *
+     1 cmplx(rpart,aipart,kind(1.d0))
       return
 c
  20   z9ln2r = (log(1.0+z) - z*(1.0-0.5*z)) / z**3
diff --git a/fvn_fnlib/zacos.f b/fvn_fnlib/zacos.f
index 074f181..be9250f 100644
--- a/fvn_fnlib/zacos.f
+++ b/fvn_fnlib/zacos.f
@@ -1,8 +1,8 @@
-      complex(8) function zacos (z)
+      complex(kind(1.d0)) function zacos (z)
       implicit none
 c april 1977 version.  w. fullerton, c3, los alamos scientific lab.
-      complex(8) z, zasin
-      real(8) pi2
+      complex(kind(1.d0)) z, zasin
+      real(kind(1.d0)) pi2
       external zasin
       data pi2 /1.5707963267 9489661923d0/
 c
diff --git a/fvn_fnlib/zacosh.f b/fvn_fnlib/zacosh.f
index 89a0626..62c27ec 100644
--- a/fvn_fnlib/zacosh.f
+++ b/fvn_fnlib/zacosh.f
@@ -1,7 +1,7 @@
-      complex(8) function zacosh (z)
+      complex(kind(1.d0)) function zacosh (z)
       implicit none
 c april 1977 version.  w. fullerton, c3, los alamos scientific lab.
-      complex(8) z, ci, zacos
+      complex(kind(1.d0)) z, ci, zacos
       external zacos
       data ci /(0.d0,1.d0)/
 c
diff --git a/fvn_fnlib/zarg.f b/fvn_fnlib/zarg.f
index 7c3c4ac..8097a5a 100644
--- a/fvn_fnlib/zarg.f
+++ b/fvn_fnlib/zarg.f
@@ -1,7 +1,7 @@
-      real(8) function zarg (z)
+      real(kind(1.d0)) function zarg (z)
       implicit none
 c april 1977 version.  w. fullerton, c3, los alamos scientific lab.
-      complex(8) z
+      complex(kind(1.d0)) z
 
 c
       zarg = 0.0
diff --git a/fvn_fnlib/zasin.f b/fvn_fnlib/zasin.f
index e26e20e..f900a57 100644
--- a/fvn_fnlib/zasin.f
+++ b/fvn_fnlib/zasin.f
@@ -1,12 +1,12 @@
-      complex(8) function zasin (zinp)
+      complex(kind(1.d0)) function zasin (zinp)
       implicit none
 c august 1980 edition.  w. fullerton, c3, los alamos scientific lab.
 c
 c ref -- l. l. pennisi, elements of complex variables,  holt, rinehart
 c and winston, 1963.  page 126.
 c
-      complex(8) zinp, z, z2, sqzp1, ci
-      real(8) d1mach,pi2,pi,rmin,r
+      complex(kind(1.d0)) zinp, z, z2, sqzp1, ci
+      real(kind(1.d0)) d1mach,pi2,pi,rmin,r
       integer nterms,i,twoi
       external d1mach
 
diff --git a/fvn_fnlib/zasinh.f b/fvn_fnlib/zasinh.f
index 92fee17..9cf7660 100644
--- a/fvn_fnlib/zasinh.f
+++ b/fvn_fnlib/zasinh.f
@@ -1,4 +1,4 @@
-      complex(8) function zasinh (z)
+      complex(kind(1.d0)) function zasinh (z)
       implicit none
 c april 1977 version.  w. fullerton, c3, los alamos scientific lab.
       complex z, ci, zasin
diff --git a/fvn_fnlib/zatan.f b/fvn_fnlib/zatan.f
index 8d60b0a..b3c1f10 100644
--- a/fvn_fnlib/zatan.f
+++ b/fvn_fnlib/zatan.f
@@ -1,13 +1,15 @@
-      complex(8) function zatan (z)
+      complex(kind(1.d0)) function zatan (z)
       implicit none
 c jan 1984 edition.  w. fullerton, los alamos scientific lab.
 c
-      complex(8) z, z2
-      real(8) pi2,sqeps,rmin,rmax,r2sml,r,d1mach,x,y,r2,xans,yans
-      external d1mach
+      complex(kind(1.d0)) z, z2
+      real(kind(1.d0)) pi2,sqeps,rmin,rmax,r2sml,r,x,y,r2,xans,yans
+      real(kind(1.d0)) d1mach
       integer nterms,i,twoi
       data pi2 /1.5707963267 9489661923d0 /
-      data nterms, sqeps, rmin, rmax, r2sml / 0, 4*0.0 /
+      data nterms, sqeps, rmin, rmax, r2sml / 0, 4*0.0d0 /
+      external d1mach
+
 c
       if (nterms.ne.0) go to 10
 c nterms = alog(eps)/alog(rbnd) where rbnd = 0.1
@@ -42,16 +44,16 @@ c
      1  seteru (
      2  55hzatan   no precision because z is too close to +i or -i,
      3  55, 2, 2)
-      if (abs(dcmplx(1.0,0.0)+z*z).lt.sqeps) call seteru (
+      if (abs(cmplx(1.0d0,0.0d0,kind(1.d0))+z*z).lt.sqeps) call seteru (
      1 50hzatan   answer lt half precision, z**2 close to -1, 50, 1, 1)
 c
  40   xans = 0.5*atan2 (2.0*x, 1.0-r2)
       yans = 0.25*log((r2+2.0*y+1.0)/(r2-2.0*y+1.0))
-      zatan = dcmplx (xans, yans)
+      zatan = cmplx (xans, yans, kind(1.d0))
       return
 c
- 50   zatan = dcmplx (pi2, 0.0)
-      if (real(z).lt.0.0) zatan = dcmplx (-pi2, 0.0)
+ 50   zatan = cmplx (pi2, 0.0d0, kind(1.d0))
+      if (real(z).lt.0.0) zatan = cmplx (-pi2, 0.0d0, kind(1.d0))
       return
 c
       end
diff --git a/fvn_fnlib/zatan2.f b/fvn_fnlib/zatan2.f
index 34e78ec..2661a98 100644
--- a/fvn_fnlib/zatan2.f
+++ b/fvn_fnlib/zatan2.f
@@ -1,8 +1,8 @@
-      complex(8) function zatan2 (csn, ccs)
+      complex(kind(1.d0)) function zatan2 (csn, ccs)
       implicit none
 c april 1977 version.  w. fullerton, c3, los alamos scientific lab.
-      complex(8) csn, ccs, zatan
-      real(8) pi
+      complex(kind(1.d0)) csn, ccs, zatan
+      real(kind(1.d0)) pi
       external zatan
       data pi / 3.1415926535 8979323846d0 /
 c
@@ -16,7 +16,7 @@ c
  10   if (abs(csn).eq.0.) call seteru (
      1  34hzatan2  called with both args zero, 34, 1, 2)
 c
-      zatan2 = dcmplx (sign(0.5*pi,real(csn)), 0.0)
+      zatan2 = cmplx (sign(0.5*pi,real(csn)), 0.0, kind(1.d0))
 c
       return
       end
diff --git a/fvn_fnlib/zatanh.f b/fvn_fnlib/zatanh.f
index cd97c62..0e61676 100644
--- a/fvn_fnlib/zatanh.f
+++ b/fvn_fnlib/zatanh.f
@@ -1,7 +1,7 @@
-      complex(8) function zatanh (z)
+      complex(kind(1.d0)) function zatanh (z)
       implicit none
 c april 1977 version.  w. fullerton, c3, los alamos scientific lab.
-      complex(8) z, ci, zatan
+      complex(kind(1.d0)) z, ci, zatan
       external zatan
       data ci /(0.,1.)/
 c
diff --git a/fvn_fnlib/zbeta.f b/fvn_fnlib/zbeta.f
index f824624..fc5d8e6 100644
--- a/fvn_fnlib/zbeta.f
+++ b/fvn_fnlib/zbeta.f
@@ -1,8 +1,8 @@
-      complex(8) function zbeta (a, b)
+      complex(kind(1.d0)) function zbeta (a, b)
       implicit none
 c july 1977 edition.  w. fullerton, c3, los alamos scientific lab.
-      complex(8) a, b, zgamma, zlbeta
-      real(8) xmax,xmin
+      complex(kind(1.d0)) a, b, zgamma, zlbeta
+      real(kind(1.d0)) xmax,xmin
       external  zgamma, zlbeta
       data xmax / 0.0 /
 c
diff --git a/fvn_fnlib/zcbrt.f b/fvn_fnlib/zcbrt.f
index 9e27f4e..24c13d2 100644
--- a/fvn_fnlib/zcbrt.f
+++ b/fvn_fnlib/zcbrt.f
@@ -1,14 +1,14 @@
-      complex(8) function zcbrt (z)
+      complex(kind(1.d0)) function zcbrt (z)
       implicit none
 c april 1977 version.  w. fullerton, c3, los alamos scientific lab.
-      complex(8) z
-      real(8) theta,zarg,r,dcbrt
+      complex(kind(1.d0)) z
+      real(kind(1.d0)) theta,zarg,r,dcbrt
       external zarg, dcbrt
 c
       theta = zarg(z) / 3.0
       r = dcbrt (abs(z))
 c
-      zcbrt = dcmplx (r*cos(theta), r*sin(theta))
+      zcbrt = cmplx (r*cos(theta), r*sin(theta), kind(1.d0))
 c
       return
       end
diff --git a/fvn_fnlib/zcosh.f b/fvn_fnlib/zcosh.f
index 6fbf1ee..5c7e7d7 100644
--- a/fvn_fnlib/zcosh.f
+++ b/fvn_fnlib/zcosh.f
@@ -1,7 +1,7 @@
-      complex(8) function zcosh (z)
+      complex(kind(1.d0)) function zcosh (z)
       implicit none
 c april 1977 version.  w. fullerton, c3, los alamos scientific lab.
-      complex(8) z, ci
+      complex(kind(1.d0)) z, ci
       data ci /(0.,1.)/
 c
       zcosh = cos (ci*z)
diff --git a/fvn_fnlib/zcot.f b/fvn_fnlib/zcot.f
index eae9c8b..fe3ee50 100644
--- a/fvn_fnlib/zcot.f
+++ b/fvn_fnlib/zcot.f
@@ -1,10 +1,10 @@
-      complex(8) function zcot (z)
+      complex(kind(1.d0)) function zcot (z)
       implicit none
 c march 1979 edition.  w. fullerton, c3, los alamos scientific lab.
-      complex(8) z
-      real(8) d1mach
-      real(8) eps, xmax, ylarge, ybig, rmin, ymin
-      real(8) x,y,x2,y2,sn2x,den
+      complex(kind(1.d0)) z
+      real(kind(1.d0)) d1mach
+      real(kind(1.d0)) eps, xmax, ylarge, ybig, rmin, ymin
+      real(kind(1.d0)) x,y,x2,y2,sn2x,den
       integer irold,irold2
       external d1mach
       data eps, xmax, ylarge, ybig, rmin, ymin / 5*0.0, 1.5 /
@@ -38,7 +38,7 @@ c
       if (den.lt.x*x2*eps .and. abs(x).gt.0.5) call seteru (65hzcot    a
      1nswer is lt half precision, x is near pi and y is near 0, 65, 1,1)
 c
-      zcot = dcmplx (sn2x/den, -sinh(y2)/den)
+      zcot = cmplx (sn2x/den, -sinh(y2)/den, kind(1.d0))
       return
 c
  20   if (abs(y).lt.ymin) call seteru (75hzcot    answer would have no p
@@ -46,10 +46,10 @@ c
       if (abs(y).lt.ybig) call seteru (69hzcot    answer lt half precisi
      1on, abs(x) is very big and abs(y) small, 69, 2, 1)
 c
-      zcot = dcmplx (0.0, 1.0/tanh(y2))
+      zcot = cmplx (0.0, 1.0/tanh(y2), kind(1.d0))
       return
 c
- 30   zcot = dcmplx (0.0, sign (1.0d0, y))
+ 30   zcot = cmplx (0.0, sign (1.0d0, y), kind(1.d0))
       return
 c
       end
diff --git a/fvn_fnlib/zexprl.f b/fvn_fnlib/zexprl.f
index afe5b2a..dd69c4c 100644
--- a/fvn_fnlib/zexprl.f
+++ b/fvn_fnlib/zexprl.f
@@ -1,4 +1,4 @@
-      complex(8) function zexprl (z)
+      complex(kind(1.d0)) function zexprl (z)
       implicit none
 c august 1980 edition.  w. fullerton, c3, los alamos scientific lab.
 c
@@ -8,8 +8,8 @@ c        cexprl(z) = (exp(x)*exp(i*y)-1)/z
 c                  = (x*exprel(x) * (1 - 2*sin(y/2)**2) - 2*sin(y/2)**2
 c                                    + i*sin(y)*(1+x*exprel(x))) / z
 c
-      complex(8) z
-      real(8) sqeps,r,xn,xln,rbnd,d1mach,alneps
+      complex(kind(1.d0)) z
+      real(kind(1.d0)) sqeps,r,xn,xln,rbnd,d1mach,alneps
       external d1mach
       integer nterms,irold,irold2,i
       data nterms, rbnd, sqeps / 0, 2*0.0 /
diff --git a/fvn_fnlib/zgamma.f b/fvn_fnlib/zgamma.f
index 7c69153..df137e8 100644
--- a/fvn_fnlib/zgamma.f
+++ b/fvn_fnlib/zgamma.f
@@ -1,8 +1,8 @@
-      complex(8) function zgamma (z)
+      complex(kind(1.d0)) function zgamma (z)
       implicit none
 c july 1977 edition.  w. fullerton, c3, los alamos scientific lab.
 c a preliminary version that is portable, but not accurate enough.
-      complex(8) z, zlngam
+      complex(kind(1.d0)) z, zlngam
       external zlngam
 c
       zgamma = exp (zlngam(z))
diff --git a/fvn_fnlib/zgamr.f b/fvn_fnlib/zgamr.f
index b314d6c..26cb677 100644
--- a/fvn_fnlib/zgamr.f
+++ b/fvn_fnlib/zgamr.f
@@ -1,11 +1,11 @@
-      complex(8) function zgamr (z)
+      complex(kind(1.d0)) function zgamr (z)
       implicit none
 c july 1977 edition.  w. fullerton, c3, los alamos scientific lab.
 c this version is an inaccurate preliminary one.  eventually this
 c routine should be a fundamental routine with no dependence on cgamma.
 c
-      complex(8) z, zlngam
-      real(8) x
+      complex(kind(1.d0)) z, zlngam
+      real(kind(1.d0)) x
       integer irold,ir
       external zlngam
 c
diff --git a/fvn_fnlib/zlbeta.f b/fvn_fnlib/zlbeta.f
index 94418e1..0d43762 100644
--- a/fvn_fnlib/zlbeta.f
+++ b/fvn_fnlib/zlbeta.f
@@ -1,8 +1,8 @@
-      complex(8) function zlbeta (a, b)
+      complex(kind(1.d0)) function zlbeta (a, b)
       implicit none
 c july 1977 edition.  w. fullerton, c3, los alamos scientific lab.
 c a preliminary version that is portable, but not accurate enough.
-      complex(8) a, b, zlngam
+      complex(kind(1.d0)) a, b, zlngam
       external zlngam
 c
       if (real(a).le.0.0 .or. real(b).le.0.0) call seteru (
diff --git a/fvn_fnlib/zlngam.f b/fvn_fnlib/zlngam.f
index 08c8e1c..deff484 100644
--- a/fvn_fnlib/zlngam.f
+++ b/fvn_fnlib/zlngam.f
@@ -1,15 +1,15 @@
-      complex(8) function zlngam (zin)
+      complex(kind(1.d0)) function zlngam (zin)
       implicit none
 c august 1980 edition.  w. fullerton c3, los alamos scientific lab.
 c eventually clngam should make use of c8lgmc for all z except for
 c z in the vicinity of 1 and 2.
-      complex(8) zin, z, corr, zlnrel, z9lgmc
-      real(8) d1mach,pi,sq2pil,bound,dxrel,rmax,cabsz
-      real(8) x,y,argsum,zarg
+      complex(kind(1.d0)) zin, z, corr, zlnrel, z9lgmc
+      real(kind(1.d0)) d1mach,pi,sq2pil,bound,dxrel,rmax,cabsz
+      real(kind(1.d0)) x,y,argsum,zarg
       integer irold,ir,i,n
       external z9lgmc, zarg, zlnrel,d1mach
-      data pi / 3.1415926535 8979324e0 /
-      data sq2pil / 0.9189385332 0467274e0 /
+      data pi / 3.1415926535 8979324d0 /
+      data sq2pil / 0.9189385332 0467274d0 /
 c
       data bound, dxrel, rmax / 3*0.0 /
 c
@@ -38,12 +38,12 @@ c abs(aimag(y)) small.
 c
       call entsrc (irold, 1)
       if (y.gt.0.0) z = conjg (z)
-      corr = exp (-dcmplx(0.0,2.0*pi)*z)
+      corr = exp (-cmplx(0.0,2.0*pi,kind(1.d0))*z)
       if (real(corr).eq.1.0 .and. aimag(corr).eq.0.0) call seteru (
      1  31hzlngam  z is a negative integer, 31, 3, 2)
 c
-      zlngam = sq2pil + 1.0 - dcmplx(0.0,pi)*(z-0.5) - zlnrel(-corr)
-     1  + (z-0.5)*log(1.0-z) - z - z9lgmc(1.0-z)
+      zlngam = sq2pil + 1.0 - cmplx(0.0,pi,kind(1.d0))*(z-0.5) - 
+     1 zlnrel(-corr) + (z-0.5)*log(1.0-z) - z - z9lgmc(1.0-z)
       if (y.gt.0.0) zlngam = conjg (zlngam)
 c
       call erroff
@@ -72,7 +72,7 @@ c
 c
       if (real(corr).eq.0.0 .and. aimag(corr).eq.0.0) call seteru (
      1  31hzlngam  z is a negative integer, 31, 3, 2)
-      corr = -dcmplx (log(abs(corr)), argsum)
+      corr = -cmplx (log(abs(corr)), argsum, kind(1.d0))
 c
 c use stirling-s approximation for large z.
 c
diff --git a/fvn_fnlib/zlnrel.f b/fvn_fnlib/zlnrel.f
index b31178f..a838537 100644
--- a/fvn_fnlib/zlnrel.f
+++ b/fvn_fnlib/zlnrel.f
@@ -1,4 +1,4 @@
-      complex(8) function zlnrel (z)
+      complex(kind(1.d0)) function zlnrel (z)
       implicit none
 c april 1977 version.  w. fullerton, c3, los alamos scientific lab.
 c
@@ -10,8 +10,8 @@ c       clog(1+z) = cmplx (alog(r), carg(1+z))
 c                 = cmplx (0.5*alog(r**2), carg(1+z))
 c                 = cmplx (0.5*alnrel(2*x+rho**2), carg(1+z))
 c
-      complex(8) z
-      real(8) dlnrel,d1mach,zarg,sqeps,x,rho
+      complex(kind(1.d0)) z
+      real(kind(1.d0)) dlnrel,d1mach,zarg,sqeps,x,rho
       external dlnrel, zarg, d1mach
       data sqeps /0.0/
 c
@@ -26,7 +26,7 @@ c
       if (rho.gt.0.375) return
 c
       x = real(z)
-      zlnrel = dcmplx (0.5*dlnrel(2.*x+rho**2), zarg(1.0+z))
+      zlnrel = cmplx (0.5*dlnrel(2.*x+rho**2), zarg(1.0+z), kind(1.d0))
 c
       return
       end
diff --git a/fvn_fnlib/zlog10.f b/fvn_fnlib/zlog10.f
index f9dea09..ffafef0 100644
--- a/fvn_fnlib/zlog10.f
+++ b/fvn_fnlib/zlog10.f
@@ -1,8 +1,8 @@
-      complex(8) function zlog10 (z)
+      complex(kind(1.d0)) function zlog10 (z)
       implicit none
 c april 1977 version.  w. fullerton, c3, los alamos scientific lab.
-      complex(8) z
-      real(8) aloge
+      complex(kind(1.d0)) z
+      real(kind(1.d0)) aloge
       data aloge / 0.4342944819 0325182765d0 /
 c
       zlog10 = aloge * log(z)
diff --git a/fvn_fnlib/zpsi.f b/fvn_fnlib/zpsi.f
index d51e0f3..fcb3cd6 100644
--- a/fvn_fnlib/zpsi.f
+++ b/fvn_fnlib/zpsi.f
@@ -1,10 +1,10 @@
-      complex(8) function zpsi (zin)
+      complex(kind(1.d0)) function zpsi (zin)
       implicit none
 c may 1978 edition.  w. fullerton, c3, los alamos scientific lab.
-      complex(8) zin, z, z2inv, corr,  zcot
+      complex(kind(1.d0)) zin, z, z2inv, corr,  zcot
       dimension bern(13)
-      real(8) bern,d1mach,pi,bound, dxrel, rmin, rbig
-      real(8) x,y,cabsz
+      real(kind(1.d0)) bern,d1mach,pi,bound, dxrel, rmin, rbig
+      real(kind(1.d0)) x,y,cabsz
       integer nterm,ndx,n,i
       external zcot, d1mach
 c
diff --git a/fvn_fnlib/zsinh.f b/fvn_fnlib/zsinh.f
index 6ae8f0f..20833a7 100644
--- a/fvn_fnlib/zsinh.f
+++ b/fvn_fnlib/zsinh.f
@@ -1,7 +1,7 @@
-      complex(8) function zsinh (z)
+      complex(kind(1.d0)) function zsinh (z)
       implicit none
 c april 1977 version.  w. fullerton, c3, los alamos scientific lab.
-      complex(8) z, ci
+      complex(kind(1.d0)) z, ci
       data ci /(0.,1.)/
 c
       zsinh = -ci*sin(ci*z)
diff --git a/fvn_fnlib/ztan.f b/fvn_fnlib/ztan.f
index 6da169c..7fb5d02 100644
--- a/fvn_fnlib/ztan.f
+++ b/fvn_fnlib/ztan.f
@@ -1,9 +1,9 @@
-      complex(8) function ztan (z)
+      complex(kind(1.d0)) function ztan (z)
       implicit none
 c march 1979 edition.  w. fullerton, c3, los alamos scientific lab.
-      complex(8) z
-      real(8) d1mach,eps, xmax, ylarge, ybig, ymin,sn2x,den
-      real(8) x,y,x2,y2
+      complex(kind(1.d0)) z
+      real(kind(1.d0)) d1mach,eps, xmax, ylarge, ybig, ymin,sn2x,den
+      real(kind(1.d0)) x,y,x2,y2
       integer irold,irold2
       external d1mach
       data eps, xmax, ylarge, ybig, ymin / 4*0.0, 1.50 /
@@ -34,7 +34,7 @@ c
       if (den.lt.x*x2*eps) call seteru (74hztan    answer lt half precis
      1ion, x is near pi/2 or 3*pi/2 and y is near 0, 74, 1, 1)
 c
-      ztan = dcmplx (sn2x/den, sinh(y2)/den)
+      ztan = cmplx (sn2x/den, sinh(y2)/den, kind(1.d0))
       return
 c
  20   if (abs(y).lt.ymin) call seteru (75hztan    answer would have no p
@@ -42,10 +42,10 @@ c
       if (abs(y).lt.ybig) call seteru (69hztan    answer lt half precisi
      1on, abs(x) is very big and abs(y) small, 69, 2, 1)
 c
-      ztan = dcmplx (0.0, tanh(y2))
+      ztan = cmplx (0.0, tanh(y2), kind(1.d0))
       return
 c
- 30   ztan = dcmplx (0.0, -sign(1.0d0, y))
+ 30   ztan = cmplx (0.0, -sign(1.0d0, y), kind(1.d0))
       return
 c
       end
diff --git a/fvn_fnlib/ztanh.f b/fvn_fnlib/ztanh.f
index 943da05..6cba088 100644
--- a/fvn_fnlib/ztanh.f
+++ b/fvn_fnlib/ztanh.f
@@ -1,6 +1,6 @@
-      complex(8) function ztanh (z)
+      complex(kind(1.d0)) function ztanh (z)
 c april 1977 version.  w. fullerton, c3, los alamos scientific lab.
-      complex(8) z, ci, ztan
+      complex(kind(1.d0)) z, ci, ztan
       external ztan
       data ci /(0.,1.)/
 c