Method setUp

SRC/element/zeroLength/ZeroLength.cpp:1836–1886

Establish the external nodes and set up the transformation matrix for orientation

// Establish the external nodes and set up the transformation matrix
// for orientation
void
ZeroLength::setUp( int Nd1, int Nd2,
		   const Vector &x,
		   const Vector &yp )
{ 
    // ensure the connectedExternalNode ID is of correct size & set values
    if (connectedExternalNodes.Size() != 2)
      opserr << "FATAL ZeroLength::setUp - failed to create an ID of correct size\n";
    
    connectedExternalNodes(0) = Nd1;
    connectedExternalNodes(1) = Nd2;

	int i;
    for (i=0; i<2; i++)
      theNodes[i] = 0;

    // check that vectors for orientation are correct size
    if ( x.Size() != 3 || yp.Size() != 3 )
	opserr << "FATAL ZeroLength::setUp - incorrect dimension of orientation vectors\n";

    // establish orientation of element for the transformation matrix
    // z = x cross yp
    Vector z(3);
    z(0) = x(1)*yp(2) - x(2)*yp(1);
    z(1) = x(2)*yp(0) - x(0)*yp(2);
    z(2) = x(0)*yp(1) - x(1)*yp(0);

    // y = z cross x
    Vector y(3);
    y(0) = z(1)*x(2) - z(2)*x(1);
    y(1) = z(2)*x(0) - z(0)*x(2);
    y(2) = z(0)*x(1) - z(1)*x(0);

    // compute length(norm) of vectors
    double xn = x.Norm();
    double yn = y.Norm();
    double zn = z.Norm();

    // check valid x and y vectors, i.e. not parallel and of zero length
    if (xn == 0 || yn == 0 || zn == 0) {
      opserr << "FATAL ZeroLength::setUp - invalid vectors to constructor\n";
    }
    
    // create transformation matrix of direction cosines
    for ( i=0; i<3; i++ ) {
	transformation(0,i) = x(i)/xn;
	transformation(1,i) = y(i)/yn;
	transformation(2,i) = z(i)/zn;
     }

}


// Check that direction is in the range of 0 to 5