Plotting contour of two functions of multiple variables

[ochristensen]

Hi

I have two functions, f1(x1,x2,x3,x4,x5) and f2(x1,x2,x3,x4,x5), which I'd like to plot with one function on each axis in a X-Y plot. The variables are limited to certain ranges, and I've been able to make scatter plots, by using nested for-statements of the variables (see fig. 1), and creating vectors of the results. This doesn't give the best result, since the use of discrete values for the variables is very obvious.

Fig. 1: Nested for-statments used to create vector

Fig. 2: Scatter plots of the two functions (for the green plot f1 is only dependent on two of the variables, making the discrete values use for calculation more obvious). The pink dots are the data points used to create the functions.

Is it possible to get the contour of the two functions with the given boundaries of the variables? I would be very nice, if I was able to just show the region of all possible values.

Sorry for my bad english, but I hope I've made myself understood.

Thanks in advance.

[RichardJ]

I'm not sure what you are showing. If you create two vectors as shown, y1f and y2f, and plot them against each other then the graph would only have one color. When you say "the contour of the two functions with the given boundaries of the variables" do you mean the envelope of the points in the scatter plot, like this:

[ochristensen]

I'm sorry, I was not clear about the plot. I've made three version of my regression. The red dots are a full quadratic and the blue and green are simplifications (the green only using two of the five variables). That's why there are more colors.

I think what you show is exactly what I'd like to do. I've tried to make a search online, but haven't been able to find out how to do it. Could you please explain?

[RichardJ]

See the attached worksheet. I didn't write this. It was posted to the forums many years ago by one "Paul W", and I just added it to my library.