Subroutine Type

Modeling

Definition

Used to specify a user-defined surface element and its derivatives for a reference surface element.  User-defined surfaces are typically used in conjunction with point-to-surface and curve-to-surface constraints.

Use

User-defined surface calling a SURSUB for the calculation of the values:

<Reference_ParamSurface

    id                  = "555"

    is_u_closed         = "TRUE"

    is_v_closed         = "TRUE"

    u_start             = "-1."

    u_end               = "1."

    v_start             = "-1."

    v_end               = "1."

    usrsub_param_string = "USER(1,400,100)"

    usrsub_dll_name     = "NULL"

 />

Calling Syntax

Fortran

SUBROUTINE SURSUB (ID, PAR, NPAR, ALPHA, BETA, IORD, IFLAG, VALUES)

C

void STDCALL SURSUB (int *id, double *par, int *npar, double *alpha, double *beta, int *iord, int *iflag, double *values)

Python

def SURSUB(id, par, npar, alpha, beta, iord, iflag):

    return values

MATLAB

function values = SURSUB(id, par, npar, alpha, beta, iord, iflag)

Input Arguments

[integer] ID

The user-defined parameter surface element identifier.

[double precision] TIME

The current simulation time.

[double precision] PAR

An array that contains the constant arguments from the list provided in the user defined statement.

[integer] NPAR

The number of entries in the PAR array.

[integer] IORD

The order of the time derivative.

0

The surface coordinates.

1

The surface first derivatives with respect to ALPHA and BETA.

2

The surface second derivatives with respect to ALPHA and BETA

[double precision] ALPHA

The value of the first independent parameter whose limits are defined by u_start and u_end.

[double precision] BETA

The value of the second independent parameter whose limits are defined by v_start and v_end.

[logical] IFLAG

The initialization flag.

Output Values

[double precision] VALUE

The output values array that contains the computed surface coordinates and first and second derivatives.  In particular, if IORD is zero, then the VALUE is an array of dimension 3 that contains X, Y, and Z coordinates as a function of u and v.

Example

def SURSUB(id, par, npar, alpha, beta, iord, iflag):

    isurtyp = int(par[0])

    cosa = cos(pi*(alpha))

    cosb = cos(pi*(beta))

    sina = sin(pi*(alpha))

    sinb = sin(pi*(beta))

    values = []

    r = par[1]

    if iord == 0:

        values.append(r*cosa*cosb)

        values.append(r*cosa*sinb)

        values.append(r*sina)

    return values