Question about vpasolve to solve a nonlinear equation with mutliple... (2024)

Hello John,

Thanks for your answer. I'm afraid that I didn't give a clear explanation about my problem. In fact, the final goal is to get the five solution of infinite solutions. For example, a problem like det(A(x1,x2...,xn))==0, where A is a matrix, x1 to xn are parameters. And N is the number of parameters, which is changeable.To me, numerical solution is enough, I don't need analytical ones.

Best,

Xiao

is fine, as is vpasolve(sin(x + y),[x,y]) or vpasolve() with any list of variables that includes all variables present in the equation works.

Yes, but if I don't the number of variables, how could I achieve this? I means if the variables is stored in a symbolic vector.

An easy example, thanks for all of your help.

If you simply do not mention any variable names to solve for, then it will solve for all of the mentioned variables. With the single output form of vpasolve() the result will be a struct with one field for each variable.

If you have a complete list of all of the variables that might potentially be present, then you can mention the complete list as the second parameter of vpasolve(). With the single output form of vpasolve() the result will be a struct with one field for each of those variables. Even the "unused" ones will have numeric values (that could be just about anything.) This is not as efficient as not mentioning any of them, or using symvar() to determine the list of variables and mentioning only those, but mentioning the complete list can make some interfaces easier since it can reduce the amount of post-processing you need to do.

Instead of that loop you have, the better approach would probably be