triangle.1.bas_fun.c

来自「主要特点 * Flexible finite element space c」· C语言 代码 · 共 60 行

/*************************************************************************
* 	tirangle.1.bas_fun.c : by R.Lie
*/

#define AREA(p0, p1, p2) \
  ((p1[0] - p0[0])*(p2[1] - p0[1]) - (p1[1] - p0[1])*(p2[0] - p0[0]))
#define NORMAL(normal, p0, p1, vol) \
  { normal[0] = (p0[1] - p1[1])/vol; \
    normal[1] = (p1[0] - p0[0])/vol; \
  }

void lambda_1(const double * p, const double ** v, void * value)
{
	double * val = (double *)value;
	double area = AREA(v[0], v[1], v[2]);
	val[0] = AREA(p, v[1], v[2]);
	val[0] /= area;
};

void lambda_2(const double * p, const double ** v, void * value)
{
	double * val = (double *)value;
	double area = AREA(v[0], v[1], v[2]);
	val[0] = AREA(v[0], p, v[2]);
	val[0] /= area;
};

void lambda_3(const double * p, const double ** v, void * value)
{
	double * val = (double *)value;
	double area = AREA(v[0], v[1], v[2]);
	val[0] = AREA(v[0], v[1], p);
	val[0] /= area;
};

void gradient_lambda_1(const double * p, const double ** v, void * value)
{
	double * val = (double *)value;
	double area = AREA(v[0], v[1], v[2]);
	NORMAL(val, v[1], v[2], area);
};

void gradient_lambda_2(const double * p, const double ** v, void * value)
{
	double * val = (double *)value;
	double area = AREA(v[0], v[1], v[2]);
	NORMAL(val, v[2], v[0], area);
};

void gradient_lambda_3(const double * p, const double ** v, void * value)
{
	double * val = (double *)value;
	double area = AREA(v[0], v[1], v[2]);
	NORMAL(val, v[0], v[1], area);
};

/*
*  end of file
**************************************************************************/