ADAS Subroutine xxnbbf
SUBROUTINE XXNBBF( NCAP7 , LAMDA , C , X ,S , IFAIL ) C C C----------------------------------------------------------------------- C C PURPOSE: Evaluates a cubic spline from its B-spline representation C C CALLING PROGRAM: VARIOUS C C SUBROUTINE: C C INPUT: (I*4) NCAP7 = NBAR+7, where NBAR is the number of C intervals (one greater than the number C of interior knots, i.e. the knots C strictly in the range LAMDA(4) to C LAMDA(NCAP+4)) over which the spline C is defined. C CONSTRAINT: NCAP7 >= 8 C C INPUT: (R*8) LAMDA() = Values of the complete set of knots C LAMDA(J), J=1,NBAR+7. C CONSTRAINT: Must be in non-decreasing C order with LAMDA(NCAP7-3) > LAMDA(4). C C INPUT: (R*8) C() = The coefficients of the B-spline N_i(x), C for i=1,2,...,nbar+3. The remaining C elements (from NBAR+4 to NBAR+7) are not C used. C C INPUT: (R*8) X = The argument x at which the cubic spline C is to be evaluated. C CONSTRAINT: C LAMDA(4) <= X <= LAMDA(NCAP7-3) C INPUT: (I*8) IFAIL = 0 : stop if any error C = 1 : continue if non-fatal error. C C OUTPUT: (R*8) S = The value of the spline, s(x) C C OUTPUT: (I*4) IFAIL = 0 : no error detected C = 1 : X does not satisfy C LAMDA(4) <= X <= LAMDA(NCAP7-3) C = 2 : NCAP7 < 8 C C C (I*4) KL = GENERAL INDEX C (I*4) KU = GENERAL INDEX C (I*4) K = GENERAL INDEX C (I*4) J = GENERAL INDEX C (R*8) E1 = GENERAL REAL C (R*8) E2 = GENERAL REAL C C ROUTINES: NONE C C AUTHORS: H. P. Summers and A. C. Lanzafame, University of Strathclyde C C DATE: 11 January 1995 C C UNIX-IDL PORT: C C VERSION: 1.1 DATE: 22-1-96 C MODIFIED: TIM HAMMOND (TESSELLA SUPPORT SERVICES PLC) C - PUT UNDER SCCS CONTROL C C VERSION: 1.2 DATE: 06-07-2004 C MODIFIED: Allan Whiteford C - Changed name from dxnbbf to xxnbbf C C----------------------------------------------------------------------- C C----------------------------------------------------------------------- INTEGER IFAIL, NCAP7 REAL*8 C(NCAP7), LAMDA(NCAP7), S REAL*8 X