Each variable that is chosen has to have a range - an upper and lower limit - so that the effect of that variable can be explored in the graphical output.

When an x or y variable is chosen, an upper and lower limit are chosen with the current value at the centre of that range. If a limit is out of a suitable range - such as an angle greater than 90º or less than 5º - then that range is clipped to the limit. If you are not happy with the limits chosen by the model, you can type in your own values.

Note that if you put a value in the lower limit cell that is higher than that in the upper limit cell, this will be accepted as sometimes people want to have graphs this way around for some display purposes.

You can select the number of points on each axis choosing between 1, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25, 27, 29 or 31 points - the number of points selected on one axis need not be the same as the number of points selected on the other axis. This is done using the drop-down combo as shown in the screen shot on the right.

The option of 1 point is included if you want to optimise for one variable only - it not mattering which variable is selected for the axis with only one point. In the case of 1 point, the axis with one point will have its value as the average of the upper and lower limits excepting the above case where one of the limits is beyond a natural limits such as an angle greater than 90º. In this case, make the upper and lower limits the same.

Another point to note is that by selecting a greater number of points, you are making it longer to calculate the entire graphical area (selecting 31 instead of 21 points along both axes will require 961 instead of 441 points - and increase of 118% on the calculation time) although you will get more precise results using a search and only have to perform half as many calculations again (this is because the search function is linear - see more about the search in Optimisations).

Copyright ©2000 Paul Grosse. All Rights Reserved