Xu is a solid professor. His lecture notes are well done, although with some typos on very important concepts/thms I had to email him to correct. Homework is very light and not a huge time commitment. Exams are very fair, all questions either coming from the lecture notes/practice questions or slight deviations of them. He answers emails very fast. Overall, good professor.

I took this class F'23 and the professor announced it was his first time teaching. Homework is super easy/light, so no stress there. Tests were difficult and harshly graded, however it is a difficult class no matter what. I would say the class is like 7/10 difficult and his exams were 7.5/10 difficult. Main complaint was that he did not prepare us for exam (easy hw, no practice exam, then you show up and he asks difficult ass shit), but other reviews seem to show he has improved.

He is helpful in OH and because he is young he is more engaged, not jaded like 60yrs old professors. His lectures are ok, he just does not do much to explain the confusing parts. However, he does post notes online so you can review them yourself. So not great, but not bad either.

The problem with the reviews from F'23 are that he gave a harsh overall grade distribution. People complained, and I guess the office reviewed the grades and changed them. I got a B+ and months later a note in my transcript appeared saying my grade was changed to A-. My overall grade was 85%.

Professor Xu at the beginning of the quarter had a bit of a weird passive-aggressive attitude toward students that tried to ask questions. However, in the latter half of the course, he became chill actually and he was pretty helpful in office hours. Professor Xu's board work is not the best though. His handwriting is a bit messy at times and he occasionally makes mistakes (on his online notes too) that I and other students have caught out. Moreover, the proofs that he writes are not usually spelled out so if you zone out for a second you're not really going to understand what you wrote in your notes since it's usually the bare bones of the proof. Also, he doesn't give out that much homework (which can be a good or bad thing depending on if you care about learning analysis). On the homework too (I think he writes them up himself?), Professor Xu tries to phrase questions in an intuitive way, but I thought it ended up being more confusing (maybe that's just me though). On the other hand, Professor Xu accommodated for the fact that we got behind in lectures and allowed us to turn in homework whenever we could. He also hosted an additional office hour (for a total of 3 office hours per week) during like week 7 and was pretty transparent about what was going to be on the final. Overall, this class felt weird since it was in between intuitive and rigorous. Professor Xu's also not as bad as that other review says, but I wouldn't say he's going to be the best professor you'll ever have either.

Having known people who took this class with him last quarter, it is clear that Xu has made some solid improvements to the course, including having much more organized lecture notes, a more fair curve, and more straightforward communication as to what we will be tested on (everything tested is something from homeworks/lectures/extra practice). Some other changes include having one midterm instead of two, and a sympathetic grading policy ("comeback mechanic", final drops midterm score and becomes worth 85%). I was warned against taking this class with him, and his current 1.0 rating is probably reflective of his teaching/testing methods last quarter, however I think this class has improved significantly since then as I've definitely had worse professors here and there is nothing about my experience this quarter that stands out as particularly bad. He also ended up making the last 3 homeworks completion based since he fell behind the class schedule, which was greatly appreciated since they can take a while and it took some stress off of the last few weeks of the quarter.

Real analysis is hard in general but Peter seems like he genuinely wants to help and is really good at explaining concepts that weren't clear the first time around. Super nice guy and OH are extremely helpful. Offers alternative grading so if you bomb the midterm, it can get dropped which is huge.

There are numerous errors in both his lectures and notes. Most of my time is spent trying to decipher his mistakes and comprehend what seems impossible to understand. Often, when he couldn't prove a theorem in class, he would either alter the theorem itself (yes, seriously) or abruptly end the session. His midterm grading rubric is absurd, deducting more than half the points for minor mistakes on all tests. Consequently, he failed at least 5 out of 30 students in the class (placing the median in the C range). Instead of taking responsibility, he blames these students, suggesting they drop the course to salvage the class median. His arrogance and lack of concern for student learning are evident in his attitude. Frankly, I fail to comprehend why he chose to teach at UCLA; it feels like he's more interested in tormenting students than educating them. Ultimately, I struggle to identify any meaningful gain from this class, except for learning to steer clear of such individuals for personal well-being. See you never Peter :)