I am testing a model in which I need to simulate closing, high and low prices (i.e. 3 dimensions of prices) of any given stock. Using the simple Geometric Brownion Motion equation I can easily simulate the closing stock price (i.e single dimension) at each step. However I am totally confused how to simulate the other 2 dimensions i.e high and low in such a manner that they dipict the possible price movement of the stock?
Thanks in advance!!