Amplitude and smoothness of the solution is
controlled by two additional blocks. The first block is a diagonal matrix with only one
element in each line and zero in the data vector. Increasing the weight of this block
reduces the amplitude of the derived P or S velocity anomalies. The second block
controls the smoothing of the solution. Each line of this block contains two equal nonzero
elements of opposite sign that correspond to all combinations of neighboring node/cells
in the parameterization grid. The data vector in this block is also zero. Increasing the
weight of this block reduces the difference between solutions in neighboring nodes,
resulting in smoothing of the computed velocity fields.