c# - OutOfMemoryException on declaration of Large Array

Question

I have to create a fairly large double array 12000ish x 55000ish. Unfortunately, I get an out of memory exception. I used to develop in Java and could change the memory settings. Is this possible with C# or is it just impossible? I am using VS 2008.

Answer 1

Each double is 8 bytes, so you're trying to allocate a single array with just over 5GB. The CLR has a per-object limit of around 2GB IIRC, even for a 64-bit CLR. In other words, it's not the total amount of memory available that's the problem (although obviously you'll have issues if you don't have enough memory), but the per-object size.

I suggest you split it into smaller arrays, perhaps behind a facade of some description. I don't believe there's any way to workaround that limit for a single array.

EDIT: You could go for an array of arrays - aka a jagged array:

double[][] array = new double[12000][];
for (int i = 0; i < array.Length; i++)
{
    array[i] = new double[55000];
}

Would that be acceptable to you?

(You can't use a rectangular array (double[,]) as that would have the same per-object size problem.)