I have a part of code that operates on large arrays of double (containing about 6000 elements at least) and executes several hundred times (usually 800) .

When I use standard loop, like that:

double[] singleRow = new double[6000];
int maxI = 800;
for(int i=0; i<maxI; i++)
{
singleRow = someObject.producesOutput();
//...
// do something with singleRow
// ...
}

The memory usage rises for about 40MB (from 40MB at the beggining of the loop, to the 80MB at the end).

When I force to use the garbage collector to execute at every iteration, the memory usage stays at the level of 40MB (the rise is unsignificant).

double[] singleRow = new double[6000];
int maxI = 800;
for(int i=0; i<maxI; i++)
{
singleRow = someObject.producesOutput();
//...
// do something with singleRow
// ...
GC.Collect()
}

But the execution time is 3 times longer! (it is crucial)

How can I force the C# to use the same area of memory instead of allocating new ones? Note: I have the access to the code of someObject class, so if it would be needed, I can change it.