Forcing fsolve to be positive

ire = fsolve(@(re) Pgls(P,BV0,FROE,B,re),re0);

is their a way to force fsolve to return a positive ire?

Answer 1

[Torsten]

Insert re^2 instead of re in your equation. When fsolve has finished, take the square root of the value returned.

Best wishes

Torsten.

Answer 2

[Matt J]

Instead of fsolve, use lsqnonlin, which lets you put bounds on the solution,

ire = lsqnonlin(@(re) Pgls(P,BV0,FROE,B,re),re0,0);