Updating Initial Conditions from last calculated values

I am trying to find a way to update the initial conditions (x0=[y1,y2,y3,y4,y5]) needed for fsolve in Simulink using Matlab Function user-defined block. The initial values are defined inside the block as a numerical vector. I want the last calculated values of the block's output to be considered as its new initial values. I see fsolve solves the problem but for only some starting iterations. Any ideas to update these values? Thanks

Answer 1

[Walter Roberson]

Make the guess a signal (or set of signals) that you input into the function block, and route the outputs back into those. You should be able to initialize them somehow.

I am not sure of the best way to initialize something like this. I know that initialization blocks exist but I have not seen how to use them. I know one way is to use a switch block that would take a constant as one input and the feed-back values as another input and use a compare on the time as the signal to decide which of the two to use. There might be a much better way than this.

[Ismaeel]

There is an Algebraic Loop problem when route back the signals from the output to the block's input.A time comparator switch is a good idea but unfortunately, it did not work for me.

[Walter Roberson]

See http://blogs.mathworks.com/simulink/2015/07/18/why-you-should-never-break-an-algebraic-loop-with-with-a-memory-block/ for how to break the loop.