We study the microbunching instability in a bunch compressor by a parallel code with some improved numerical algorithms. The two-dimensional charge/current distribution is represented by a Fourier series. with coefficients determined through Monte Carlo sampling over an ensemble of tracked points. This gives a globally smooth distribution with low noise. https://www.roneverhart.com/Arjo-Sara-Stedy-Stand-Assist-Manual-Patient-Standing-Aid/