Hi, I am an early twenties woman just moved to London almost a month ago and was walking home after having picked up a parcel from my local Tesco. I live in the Bethnal Green/Cambridge Heath area, so not the best but I don't think it's the worst either(?).

Anyways, a homeless person just approached me and for some reason I didn't walk away like I would usually do, as I was a bit spaced out. He asked me if I could come close by to help pay for his monthly shelter at the church which would have ended up being like 17 gbp.

I considered it, especially knowing there are homeless shelters in the area (and he was following me so it was a bit awkward), but told me it's cash and I don't do cash and was not going to follow a random person to somewhere unknown even though he said it was "just around the corner" so I finally told him off and he simply left, complaining about how he is used to being ignored.

I have very mixed feelings about the encounter and wish it didn't happen. Checked the map, there does seem to be a shelter in the direction he pointed me towards but it was not "just around the corner" as he put it.

This happened on a1209, between the McDonald's and Bethnal Green tube station.

Did I just dodge a huge bullet? I feel bad - I wish I could help people in need but I feel like I would have risked too much for no reason. The entire encounter felt off somehow. I guess I'm just shocked at the possibility of someone literally picking me off the street and trying to trick me so he could hurt me, and looking believable. I must have been very lucky in my life to have never felt this, and I hate having to become cold/heartless/etc to make sure I stay safe.

Thanks for reading, I just needed to tell this to someone I guess.

Hi,

I'm studying for an exam coming up soon and I'm trying to figure out what is the functional difference between these two approaches:

#pragma omp parallel for
	for(unsigned int i = 0; i < G.Out.bucket_count(); i++){
		for(auto itv = G.Out.begin(i); itv != G.Out.end(i); itv++){

			unsigned int v = itv->first;

			#pragma omp parallel for
			for(unsigned int j = 0; j < G.Out[v]._map.bucket_count(); j++){
				for(auto ite = G.Out[v]._map.begin(j); ite != G.Out[v]._map.end(j); ite++){

					unsigned int w = ite->first;

					if(o[v] > o[w])
					 #pragma omp critical
					 p[o[v]] = min(p[o[v]],o[w]);

				}
			}

		}

and

	#pragma omp parallel for
	for(unsigned int i = 0; i < G.Out.bucket_count(); i++){
		for(auto itv = G.Out.begin(i); itv != G.Out.end(i); itv++){

			unsigned int v = itv->first;

			if(p[v] == v){

				unsigned int parent = v; //=p[v]

				#pragma omp parallel for reduction(min : parent)
				for(unsigned int j = 0; j < G.Out[v]._map.bucket_count(); j++){
					for(auto ite = G.Out[v]._map.begin(j); ite != G.Out[v]._map.end(j); ite++){
						unsigned int w = ite->first;
						if(v > w)
						 parent = min(parent,w);
					}
				}

				p[v] = parent;
				if(p[v] != v) changes = 1;

			}

		}
	}

In the first example, the minimum between the two values is calculated using a critical section, while the second one uses a reduction. Both work, and they seem equivalent to me, when would one choose one or the other?

Thanks, and sorry if the question is too niche. Any other info about OpenMP is greatly appreciated :D