Subtraction of values from another parameters

[Mystery]

Hello,

I draw some graphs of memory usage and I would like to subtract values from Memory free value.

For example: System.Memory.Physical.Used - System.Memory.Physical.Buffers - System.Memory.Physical.Cached to get real used physical memory.

Is it possible to subtract these values in Transformation? If so, how can I call these values? If not, what is the best way to do that? I am new to NetXMS so I am little confused. Thank you

[Mystery]

Ok, I solved it by script:

sub main()
{
val1 = GetDCIValueByDescription($node, "Used physical memory");
val2 = GetDCIValueByDescription($node, "Physical memory used for buffers");
val3 = GetDCIValueByDescription($node, "Physical memory used for cache");
return val1 - val2 - val3;
}