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CFX Post Expressions number decimals

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Old   November 29, 2013, 15:48
Default CFX Post Expressions number decimals
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Hi, there,

I am creating an expression in CFX post using the trendline created in the Excel as following:

(-798936626.593750*z^6/1[m^6] + 4687121164.076870*z^5/1[m^5] - 11450097996.080200*z^4/1[m^4] + 14908481102.838800*z^3/1[m^3] - 10912008484.852500*z^2/1[m^2] + 4256979247.793130*z/1[m] - 691537634.412929)*1[K]

when I evaluate the expression using 0.91 for z, the CFX gives me wrong number 1536K, while Excel is 762K.

How do I change the decimal setup/precision in CFX?

Thanks.

Nan
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Old   November 30, 2013, 05:40
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Glenn Horrocks
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When you start the solver select double precision. But I vaguely recall that CEL is evaluated in single precision even with the rest of the numerics being double precision. I am not certain of this, but keep it is mind.
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Old   November 30, 2013, 09:29
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Hi, Glenn,

Thanks. I do have double precision turned on for solver.
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Old   December 13, 2013, 05:39
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maybe you can use the "function"-function from cfx pre to overcome the rounding errors if the expression is supposed to be used in the simulation.
Be very careful about the resolution of the points being used in the function, because they will be interpolated piece-wise between two points.
You can also import data (like *.csv) for comparison in post - directly within the graph-tool.
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