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mcc/bsplines/fpgivs.f

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+      recursive subroutine fpgivs(piv,ww,cos,sin)
+      implicit none
+c  subroutine fpgivs calculates the parameters of a givens
+c  transformation .
+c  ..
+c  ..scalar arguments..
+      real*8 piv,ww,cos,sin
+c  ..local scalars..
+      real*8 dd,one,store
+c  ..function references..
+      real*8 abs,sqrt
+c  ..
+      one = 0.1e+01
+      store = abs(piv)
+      if(store.ge.ww) dd = store*sqrt(one+(ww/piv)**2)
+      if(store.lt.ww) dd = ww*sqrt(one+(piv/ww)**2)
+      cos = ww/dd
+      sin = piv/dd
+      ww = dd
+      return
+      end