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/*
* Copyright (C) 1998, 2000-2007, 2010, 2011, 2012, 2013 SINTEF ICT,
* Applied Mathematics, Norway.
*
* Contact information: E-mail: tor.dokken@sintef.no
* SINTEF ICT, Department of Applied Mathematics,
* P.O. Box 124 Blindern,
* 0314 Oslo, Norway.
*
* This file is part of SISL.
*
* SISL is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as
* published by the Free Software Foundation, either version 3 of the
* License, or (at your option) any later version.
*
* SISL is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public
* License along with SISL. If not, see
* <http://www.gnu.org/licenses/>.
*
* In accordance with Section 7(b) of the GNU Affero General Public
* License, a covered work must retain the producer line in every data
* file that is created or manipulated using SISL.
*
* Other Usage
* You can be released from the requirements of the license by purchasing
* a commercial license. Buying such a license is mandatory as soon as you
* develop commercial activities involving the SISL library without
* disclosing the source code of your own applications.
*
* This file may be used in accordance with the terms contained in a
* written agreement between you and SINTEF ICT.
*/
#include "sisl-copyright.h"
/*
*
* $Id: sh1462.c,v 1.1 1994-04-21 12:10:42 boh Exp $
*
*/
#define SH1462
#include "sislP.h"
#if defined(SISLNEEDPROTOTYPES)
typedef void (*fshapeProc)(double [],double [],int,int,int *);
#else
typedef void (*fshapeProc)();
#endif
#if defined(SISLNEEDPROTOTYPES)
void
sh1462(fshapeProc fshape,SISLCurve *vboundc[],int icurv,
double etwist[],double etang[],double eder[],int *jstat)
#else
void sh1462(fshape,vboundc,icurv,etwist,etang,eder,jstat)
fshapeProc fshape;
double etwist[],etang[],eder[];
SISLCurve *vboundc[];
int icurv,*jstat;
#endif
/*
*********************************************************************
*
* PURPOSE : Given a three sided vertex region, evaluate the first
* blending surface in the corner lying in the middle of the
* vertex region. Compute the tangent vectors in the middle
* vertex along the inner boundaries of the region.
*
*
*
* INPUT : fshape - Application driven routine that gives the user an
* ability to change the middle point of the region
* (the vertex at which the blending surfaces meet),
* and the tangent vectors in the middle point along
* the curves which divedes the region.
* vboundc - Position and cross-tangent curves around the vertex
* region. For each edge of the region position and cross-
* tangent curves are given. The curves follow each other
* around the region and are oriented counter-clock-wise.
* The dimension of the array is 6, i.e. 2*icurv.
* icurv - Number of sides. icurv = 3.
* etwist - Twist-vectors of the corners of the vertex region. The
* first element of the array is the twist in the corner
* before the first edge, etc. The dimension of the array
* is 3*kdim.
*
*
* OUTPUT : etang - Tangent vectors at the midpoint of the vertex region.
* The dimension is icurv*idim.
* eder - Value, first and second derivative of the first blending
* surface in the corner at the midpoint. The sequence is the
* following : Value, 1. derivative in 1. parameter direction,
* 1. derivative in the 2. parameter direction, 2. derivative
* in the 1. parameter direction, mixed derivative and 2.
* derivative in the 2. parameter direction. Dimension 6*idim.
* jstat - status messages
* > 0 : warning
* = 0 : ok
* < 0 : error
*
*
* METHOD : Evaluate the Gregory Charrot function in the midpoint of the
* vertex region. Compute the wanted derivatives.
*
* REFERENCES :
*
* USE : 3D geometry only.
*
*-
* CALLS : sh1466 - Evaluate the Gregory Charrot function.
*
* WRITTEN BY : Vibeke Skytt, SI, 03.90.
*
*********************************************************************
*/
{
int kstat = 0; /* Status variable. */
int kder = 2; /* Number of derivatives to evaluate. */
int ki; /* Counter. */
int kdim = 3; /* Dimension of geometry space. */
double tonethird = (double)1.0/(double)3.0; /* 1/3 */
double tonesixth = (double)1.0/(double)6.0; /* 1/6 */
double sbar[3]; /* Barycentric coordinates of point to evaluate. */
double sder[18]; /* Value and derivatives of blending. */
/* Set up the barycentric coordinates of the midpoint of the region. */
sbar[0] = sbar[1] = sbar[2] = tonethird;
/* Evaluate the Gregory Charrot function at the midpoint. */
sh1466(vboundc,etwist,kder,sbar,sder,&kstat);
if (kstat < 0) goto error;
/* Compute tangent vectors. */
for (ki=0; ki<kdim; ki++)
{
etang[ki] = -sder[kdim+ki]*tonethird + sder[2*kdim+ki]*tonesixth;
etang[kdim+ki] = sder[kdim+ki]*tonesixth - sder[2*kdim+ki]*tonethird;
etang[2*kdim+ki] = sder[kdim+ki]*tonesixth + sder[2*kdim+ki]*tonesixth;
}
/* Application driven routine to alter the midpoint and tangents in the
midpoint. */
fshape(sder,etang,kdim,icurv,&kstat);
if (kstat < 0) goto error;
/* Copy value and 1. derivatives of first patch. */
memcopy(eder,sder,kdim,DOUBLE);
memcopy(eder+kdim,etang+2*kdim,kdim,DOUBLE);
memcopy(eder+2*kdim,etang,kdim,DOUBLE);
/* Compute 2. derivatives. */
for (ki=0; ki<kdim; ki++)
{
eder[3*kdim+ki] = sder[3*kdim+ki]*tonesixth*tonesixth
+ (double)2.0*sder[4*kdim+ki]*tonesixth*tonesixth
+ sder[5*kdim+ki]*tonesixth*tonesixth;
eder[4*kdim+ki] = -sder[3*kdim+ki]*tonesixth*tonethird
+ sder[4*kdim+ki]*tonesixth*(tonesixth - tonethird)
+ sder[5*kdim+ki]*tonesixth*tonesixth;
eder[5*kdim+ki] = sder[3*kdim+ki]*tonethird*tonethird
- (double)2.0*sder[4*kdim+ki]*tonethird*tonesixth
+ sder[5*kdim+ki]*tonesixth*tonesixth;
}
*jstat = 0;
goto out;
/* Error in a lower level function. */
error:
*jstat = kstat;
goto out;
out :
return;
}
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