+++ /dev/null
-C Output from Public domain Ratfor, version 1.0
- subroutine sslvrg(penalt,dofoff,x,y,w,ssw, n, knot,nk,coef,
- * sz,lev, crit,icrit, lambda, xwy, hs0,hs1,hs2,hs3,
- * sg0,sg1,sg2,sg3, abd,p1ip,p2ip,ld4,ldnk,info)
-
-C Purpose :
-C Compute smoothing spline for smoothing parameter lambda
-C and compute one of three `criteria' (OCV , GCV , "df match").
-C See comments in ./sbart.f from which this is called
-
- integer n,nk,icrit,ld4,ldnk,info
- DOUBLE precision penalt,dofoff,x(n),y(n),w(n),ssw,
- & knot(nk+4), coef(nk),sz(n),lev(n), crit, lambda,
- * xwy(nk), hs0(nk),hs1(nk),hs2(nk),hs3(nk),
- * sg0(nk),sg1(nk),sg2(nk),sg3(nk), abd(ld4,nk),
- & p1ip(ld4,nk),p2ip(ldnk,nk)
-
- EXTERNAL bvalue
- double precision bvalue
-C local variables
- double precision vnikx(4,1),work(16)
- integer i,ileft,j,mflag, lenkno, ilo
- double precision b0,b1,b2,b3,eps, xv,rss,df, sumw
-c
-c integer interv
-c external interv
-
- lenkno = nk+4
- ileft = 1
- eps = 1d-11
- ilo = 1
-
-C compute the coefficients coef() of estimated smooth
-
- do 1 i=1,nk
- coef(i) = xwy(i)
- abd(4,i) = hs0(i)+lambda*sg0(i)
- 1 continue
-
- do 4 i=1,(nk-1)
- abd(3,i+1) = hs1(i)+lambda*sg1(i)
- 4 continue
-
- do 6 i=1,(nk-2)
- 6 abd(2,i+2) = hs2(i)+lambda*sg2(i)
-
- do 8 i=1,(nk-3)
- 8 abd(1,i+3) = hs3(i)+lambda*sg3(i)
-
-c factorize banded matrix abd:
- call dpbfa(abd,ld4,nk,3,info)
- if(info.ne.0) then
-C matrix could not be factorized -> ier := info
- return
- endif
-c solve linear system (from factorize abd):
- call dpbsl(abd,ld4,nk,3,coef)
-
-C Value of smooth at the data points
- do 12 i=1,n
- xv = x(i)
- 12 sz(i) = bvalue(knot,coef,nk,4,xv,0)
-
-C Compute the criterion function if requested
-
- if(icrit .eq. 0)then
- return
- else
-C --- Ordinary or Generalized CV or "df match" ---
-
-C Get Leverages First
- call sinerp(abd,ld4,nk,p1ip,p2ip,ldnk,0)
- do 16 i=1,n
- xv = x(i)
- call interv(knot(1), nk+1, xv, ileft, mflag)
- if(mflag .eq. -1) then
- ileft = 4
- xv = knot(4)+eps
- else if(mflag .eq. 1) then
- ileft = nk
- xv = knot(nk+1) - eps
- endif
- j=ileft-3
-C call bspvd(knot,4,1,xv,ileft,4,vnikx,work)
- call bsplvd(knot,lenkno,4,xv,ileft,work,vnikx,1)
- b0=vnikx(1,1)
- b1=vnikx(2,1)
- b2=vnikx(3,1)
- b3=vnikx(4,1)
- lev(i) = (
- & p1ip(4,j)*b0**2 + 2.d0*p1ip(3,j)*b0*b1 +
- * 2.d0*p1ip(2,j)*b0*b2 + 2.d0*p1ip(1,j)*b0*b3 +
- * p1ip(4,j+1)*b1**2 + 2.d0*p1ip(3,j+1)*b1*b2 +
- * 2.d0*p1ip(2,j+1)*b1*b3 + p1ip(4,j+2)*b2**2 +
- & 2.d0*p1ip(3,j+2)*b2*b3 + p1ip(4,j+3)*b3**2
- & )*w(i)**2
- 16 continue
-
-C Evaluate Criterion
-
- if(icrit .eq. 1)then
-C Generalized CV
- rss = ssw
- df = 0d0
- sumw = 0d0
-c w(i) are sqrt( wt[i] ) weights scaled in ../R/smspline.R such
-c that sumw = number of observations with w(i) > 0
- do 24 i=1,n
- rss = rss + ((y(i)-sz(i))*w(i))**2
- df = df + lev(i)
- sumw = sumw + w(i)**2
- 24 continue
-
- crit = (rss/sumw)/((1d0-(dofoff + penalt*df)/sumw)**2)
-c call dblepr("spar", 4, spar, 1)
-c call dblepr("crit", 4, crit, 1)
-
- else if(icrit .eq. 2) then
-C Ordinary CV
- crit = 0d0
- do 30 i = 1,n
- 30 crit = crit + (((y(i)-sz(i))*w(i))/(1-lev(i)))**2
- crit = crit/n
-c call dblepr("spar", 4, spar, 1)
-c call dblepr("crit", 4, crit, 1)
- else
-C df matching
- crit = 0d0
- do 32 i=1,n
- 32 crit = crit+lev(i)
- crit = 3 + (dofoff-crit)**2
- endif
- return
- endif
-C Criterion evaluation
- end