4.8.3.4. CUBSPL

Table 4.53 Function Name

Language type	SubRoutine
FORTRAN	call rd_cubspl(xval, zval, identity, order, array, errflg) or cubspl(xval, zval, identity, order, array, errflg)
C/C++	rd_cubspl(xval, zval, identity, order, &array[0], &errflg) or cubspl(xval, zval, identity, order, &array[0], &errflg)

Table 4.54 Parameter information

VariableName	Size	Description
xval	double	An input variable for the CUBSPL function. Generally, this variable is time or a function that returns a real number.
zval	double	An input variable for the CUBSPL function. The second variable is necessary for three dimensional spline functions. This variable must be a function that returns a real number. Otherwise, 0 is applied. \(\begin{aligned} & \begin{matrix} \left\{ \begin{matrix} {{y}_{1}}=f(x,{{z}_{1}}) \\ {{y}_{2}}=f(x,{{z}_{2}}) \\ \end{matrix} \right., & {{z}_{1}}<z<{{z}_{2}} \\ \end{matrix} \\ & y={{y}_{1}}+\frac{(z-{{z}_{1}})({{y}_{2}}-{{y}_{1}})}{{{z}_{2}}-{{z}_{1}}} \\ \end{aligned}\)
identity	double	The identity of Spline.
order	int	The interpolation methods for the functions (return the value if 0, return calculation for 1st order differential equation if 1, and return calculation for 2nd order differential equation if 2) order = 0 \(array=f(x,spline\_data)\) order = 1 \(array=\frac{d}{dx}\left( f(x,spline\_data) \right)\) order = 2 \(array=\frac{{d}^{2}}{d{x}_{2}}\left( f(x,spline\_data) \right)\)
array	double
errflg	int	Error flag. If the result of this argument is zero, there’s no error

Listing 4.40 Fortran code for CUBSPL

 C---- SUB. MOTION_USUB
       SUBROUTINE MOTION_USUB
     &          (TIME,UPAR,NPAR,IORD,IFLAG,RESULT)
 C---- TO EXPORT * SUBROUTINE
       !DEC$ ATTRIBUTES DLLEXPORT,C::MOTION_USUB

 C---- INCLUDE SYSTEM CALL
       INCLUDE 'SYSCAL.F'

 C---- DEFINE VARIABLES
 C     Parameter Information
 C     TIME   : Simulation time of RD/Solver. (Input)
 C     UPAR   : Parameters defined by user. (Input)
 C     NPAR   : Number of user parameters. (Input)
 C     IORD   : Integrator order. (Input)
 C     IFLAG  : When RD/Solver initializes arrays, the flag is true. (Input)
 C     RESULT : Returned value. (Output)

       DOUBLE PRECISION TIME, UPAR(*)
       INTEGER NPAR, IORD
       LOGICAL IFLAG
       DOUBLE PRECISION RESULT[REFERENCE]

 C---- USER STATEMENT
 C---- Local Variable Definition
       double precision result_order(1)
       double precision result_order0(1)
       double precision result_order1(1)
       double precision result_order2(1)
       integer splineID
       integer iorder
       integer iflagRest
       logical ERRFLG
       integer errorID

 C---- Assign Parameter
       splineID = int(UPAR(1))
       iorder = int(UPAR(2))
       iflagTest = int(UPAR(3))

 C---- Call RD_CUBSPL to get the result of spline
       if (iflagTest) then
         call RD_CUBSPL(time,0,splineID,0,result_order0(1),ERRFLG)
         errorID = 1000
         call ERRMES(ERRFLG,'Error : order 0',errorID,'CUBSPL')

         call RD_CUBSPL(time,0,splineID,1,result_order1(1),ERRFLG)
         errorID = 1001
         call ERRMES(ERRFLG,'Error : order 1',errorID,'CUBSPL')

         call RD_CUBSPL(time,0,splineID,2,result_order2(1),ERRFLG)
         errorID = 1002
         call ERRMES(ERRFLG,'Error : order 2',errorID,'CUBSPL')

 C------- Assign the returned value to User Subroutine
         if (iorder .eq. 0) then
             RESULT = result_order0(1)
         else if (iorder .eq. 1) then
             RESULT = result_order1(1)
         else if (ioerder .eq. 2) then
             RESULT = result_order2(1)
         endif
       else
         call RD_CUBSPL(time,0,splineID,iorder,result_order(1),ERRFLG)
         errorID = 2000
         call ERRMES(ERRFLG,'Error : order',errorID,'CUBSPL')

 C------- Assign the returned value to User Subroutine
         RESULT = result_order(1)
       endif

       RETURN
       END

Listing 4.41 C/C++ code for CUBSPL

 #include "stdafx.h"
 #include "DllFunc.h"

 Cubspl_C_API void __cdecl motion_usub
   (double time, double upar[], int npar, int iord, int iflag, double* result)
 {
   using namespace rd_syscall;
   // Parameter Information
   //   time    :  Simulation time of RD/Solver. (Input)
   //   upar    :  Parameters defined by user. (Input)
   //   npar    :  Number of user parameters. (Input)
   //   iord    :  Integrator order. (Input)
   //   iflag   :  When RD/Solver initializes arrays, the flag is true. (Input)
   //   result  :  Returned value. (Output)

   // User Statement
   // Local Variable Definition
   double result_order0 = 0.0;
   double result_order1 = 0.0;
   double result_order2 = 0.0;
   int splineID;
   int iorder = 0;
   int iflagTest = 0;
   int ERRFLG = 0;
   int errorID = 0;

   // Assign Parameters
   splineID = (int)upar[0];
   iorder = (int)upar[1];
   iflagTest = (int)upar[2];

   // Call RD_CUBSPL to collect information for calculations
   if (iflagTest)
   {
       rd_cubspl(time,0,splineID,0,&result_order0,&ERRFLG);
       errorID = 1000;
       errmes(ERRFLG,"Error : order 0",errorID,"CUBSPL");

       rd_cubspl(time,0,splineID,1,&result_order1,&ERRFLG);
       errorID = 1001;
       errmes(ERRFLG,"Error : order 1",errorID,"CUBSPL");

       rd_cubspl(time,0,splineID,2,&result_order2,&ERRFLG);
       errorID = 1002;
       errmes(ERRFLG,"Error : order 2",errorID,"CUBSPL");

       // Assign the returned value to User Subroutine
       if (iorder == 0)
       {
         *result = result_order0;
       }
       else if (iorder == 1)
       {
         *result = result_order1;
       }
       else if (iorder ==2)
       {
         *result = result_order2;
       }
   }
   else
   {
       // Assign the returned value to User Subroutine
       rd_cubspl(time,0,splineID,iorder,result,&ERRFLG);
       errorID = 2000;
       errmes(ERRFLG,"Error : order",errorID,"CUBSPL");
   }

 }