[xuegy]

Hello all,

I have encountered a memory trouble. My workstation has 128GB memory and my case will occupy about 80GB memory while running. I need to save 2 surfaces instead of the whole result so I added functions in my controlDict. However everytime this sampling code leads to an out of memory problem.

functions
{
	mysurfaces
	{
		type            surfaces;
		functionObjectLibs
		(
			"libsampling.so"
		);
		writeControl    adjustableRunTime;
		writeInterval   0.005;
		surfaceFormat   vtk;
		interpolationScheme cellPoint;
		fields
		(
			p
			U
		);
		surfaces
		(
			surfaceXZ
			{
				type plane;
				basePoint (0.1001 0.1001 0);
				normalVector (0 1 0);
			}
			surfaceYZ
			{
				type plane;
				basePoint (0.1001 0.1001 0);
				normalVector (1 0 0);
			}
		);
	}
	myline
	{
		type            sets;
		functionObjectLibs
		(
			"libsampling.so"
		);
		writeControl    adjustableRunTime;
		writeInterval   0.005;
		setFormat   raw;
		interpolationScheme cellPoint;
		fields
		(
			U
		);
		sets
		(
			lineZ
			{
				type        uniform;
				axis        z;
       				start       (0.1001 0.1001 0);
        			end         (0.1001 0.1001 0.8);
        			nPoints     401;
			}
		);
	}
}

So it is incredible that sampling a surface will occupy more that 40GB memory. I don't want to modify the mesh or the solver. So is there any method to reduce the memory usage when sampling these surfaces?

Thanks

[blais.bruno]

That is indeed a very troubling amount of memory.

Does the same error occur if you try to save only P instead of U and P or it does not change? Are you using the latest version? This seems very anormal, so there might be an underlying bug that manifest itself only for very large cases...

Originally Posted by xuegy

Hello all,

I have encountered a memory trouble. My workstation has 128GB memory and my case will occupy about 80GB memory while running. I need to save 2 surfaces instead of the whole result so I added functions in my controlDict. However everytime this sampling code leads to an out of memory problem.

functions
{
    mysurfaces
    {
        type            surfaces;
        functionObjectLibs
        (
            "libsampling.so"
        );
        writeControl    adjustableRunTime;
        writeInterval   0.005;
        surfaceFormat   vtk;
        interpolationScheme cellPoint;
        fields
        (
            p
            U
        );
        surfaces
        (
            surfaceXZ
            {
                type plane;
                basePoint (0.1001 0.1001 0);
                normalVector (0 1 0);
            }
            surfaceYZ
            {
                type plane;
                basePoint (0.1001 0.1001 0);
                normalVector (1 0 0);
            }
        );
    }
    myline
    {
        type            sets;
        functionObjectLibs
        (
            "libsampling.so"
        );
        writeControl    adjustableRunTime;
        writeInterval   0.005;
        setFormat   raw;
        interpolationScheme cellPoint;
        fields
        (
            U
        );
        sets
        (
            lineZ
            {
                type        uniform;
                axis        z;
                       start       (0.1001 0.1001 0);
                    end         (0.1001 0.1001 0.8);
                    nPoints     401;
            }
        );
    }
}

So it is incredible that sampling a surface will occupy more that 40GB memory. I don't want to modify the mesh or the solver. So is there any method to reduce the memory usage when sampling these surfaces?

Thanks

[xuegy]

I'm using the latest version of deb pack. I've tested this case on a half-size mesh(1/8) and everything runs smoothly.

If I only save one surface of U it's safe. About 15GB will be occupied when writing. But if I add the line sampling it will crash again. I should go back and test each value separately so that I can know where is the problem.

Originally Posted by blais.bruno

That is indeed a very troubling amount of memory.

Does the same error occur if you try to save only P instead of U and P or it does not change? Are you using the latest version? This seems very anormal, so there might be an underlying bug that manifest itself only for very large cases...