What is the test for remand in a criminal case where a defendant has been found guilty of a sexual assault and remand?

"Generally, when the record shows that the trial court proceeded with sentencing on the erroneous assumption it lacked discretion, remand is necessary so that the trial court may have the opportunity to exercise its sentencing discretion at a new sentencing hearing. [Citations.] Defendants are entitled to 'sentencing decisions made in the exercise of the "informed discretion" of the sentencing court,' and a court that is unaware of its discretionary authority cannot exercise its informed discretion. [Citation.]" (People v. Brown (2007) 147 Cal.App.4th 1213, 1228.)