cell_matrix(i,j)
+=
// This first term is
- // ((lambda+mu) d_i u_i, d_j v_j).
+ // (lambda d_i u_i, d_j v_j)
+ // + (mu d_i u_j, d_j v_i).
// Note that
// ``shape_grad(i,q_point)''
// returns the
// gradient of
+ // the only
+ // nonzero
+ // component of
// the i-th shape
// function at
// quadrature
// point
// q_point. The
// component
- // ``comp(i)'',
+ // ``comp(i)'' of
+ // the gradient,
// which is the
// derivative of
+ // this only
+ // nonzero vector
+ // component of
// the i-th shape
// function with
// respect to the
(
(fe_values.shape_grad(i,q_point)[component_i] *
fe_values.shape_grad(j,q_point)[component_j] *
- (lambda_values[q_point] +
- mu_values[q_point]))
+ lambda_values[q_point])
+ +
+ (fe_values.shape_grad(i,q_point)[component_j] *
+ fe_values.shape_grad(j,q_point)[component_i] *
+ mu_values[q_point])
+
// The second term is
// (mu nabla u_i, nabla v_j).