在Fortran PowerStation 4.0中自带IMSL,可看帮助文件，新建一个工程，加入它的例子bsint_ex.for
（.for为标准fortran语言格式文本）
C
C Compute the spline interpolant, returning the B-spline coefficients.
C
C In this example, a spline interpolant S, to F(X) = SQRT(X), is
C computed. The interpolated values are then compared with the exact
C function values using the IMSL routine BSVAL.
C
C Output:
C
C X S(X) Error
C
C 0.0000 0.0000 0.000000
C 0.1250 0.2918 0.061781
C 0.2500 0.5000 0.000000
C 0.3750 0.6247 -0.012311
C 0.5000 0.7071 0.000000
C 0.6250 0.7886 0.002013
C 0.7500 0.8660 0.000000
C 0.8750 0.9365 -0.001092
C 1.0000 1.0000 0.000000
C
USE MSIMSLMD
C
INTEGER KORDER, NDATA, NKNOT
PARAMETER (KORDER=3, NDATA=5, NKNOT=NDATA+KORDER)
C
INTEGER I, NCOEF, NOUT
DOUBLE PRECISION BSCOEF(NDATA), BT, F, FDATA(NDATA), DBLE,
& DSQRT, X, XDATA(NDATA), XKNOT(NKNOT), XT
INTRINSIC DBLE, DSQRT
C Define function
F(X) = DSQRT(X)
C Set up interpolation points
DO 10 I=1, NDATA
XDATA(I) = DBLE(I-1)/DBLE(NDATA-1)
FDATA(I) = F(XDATA(I))
10 CONTINUE
C Generate knot sequence
CALL DBSNAK (NDATA, XDATA, KORDER, XKNOT)
C Interpolate
CALL DBSINT (NDATA, XDATA, FDATA, KORDER, XKNOT, BSCOEF)
C Get output unit number
CALL UMACH (2, NOUT)
C Write heading
WRITE (NOUT,99999)
C Print on a finer grid
NCOEF = NDATA
XT = XDATA(1)
C Evaluate spline
BT = DBSVAL(XT,KORDER,XKNOT,NCOEF,BSCOEF)
WRITE (NOUT,99998) XT, BT, F(XT) - BT
DO 20 I=2, NDATA
XT = (XDATA(I-1)+XDATA(I))/2.0D0
C Evaluate spline
BT = DBSVAL(XT,KORDER,XKNOT,NCOEF,BSCOEF)
WRITE (NOUT,99998) XT, BT, F(XT) - BT
XT = XDATA(I)
C Evaluate spline
BT = DBSVAL(XT,KORDER,XKNOT,NCOEF,BSCOEF)
WRITE (NOUT,99998) XT, BT, F(XT) - BT
20 CONTINUE
99998 FORMAT (' ', F6.4, 15X, F8.4, 12X, F11.6)
99999 FORMAT (/, 6X, 'X', 19X, 'S(X)', 18X, 'Error', /)
END