Mark Bell's profile - activity

I want to perform some statistical sampling and to do this I need to uniformly randomly choose an integer from [0, N) where $N \approx 10^{50}$. It appears that there are several plausible ways to do this in Sage:

1) randint(0, N-1)

However, the standard Python random library appears to have some non-uniformity, for example see this ticket.

2) import numpy; numpy.random.randint(0, N)

However, since N is so large, this raises

ValueError: high is out of bounds for int64

3) ZZ.random_element(0, N)

Do either of the issues that methods 1) and 2) suffer from apply to method 3)? That is, is 3) the correct way to integers uniformly at random?

Sage allows me to get the representation of a Graph, G, in the dot language by using the method

G.graphviz_string()

I can even have this string written directly to a file by using:

G.graphviz_to_file_named('my_graph_file.dot')

Is there a way of reloading G from such a file? I tried doing

G = Graph('my_graph_file.dot')

G = Graph(open('my_graph_file.dot'))

G = Graph(open('my_graph_file.dot').read())

Where the contents of 'my_graph_file.dot' are:

graph MyGraph{

foo -- {bar}

bar -- {foo; bas}

bas -- {bar}

}

But none of these worked.