Extract Data by 2D Interpolation

Forum|Forum|2 years ago
March 19, 2024
1 reply
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Hello everyone,

I am encountering difficulties setting up a 2D interpolation in Mathcad. My objective is to determine the parameters A, B, C, and D for two given inputs: ratio "r" and delta "δ."

The dataset is categorized into four groups based on Ratios: 0.25, 0.5, 2, and 4. Each group is associated with a specific set of Deltas and corresponding parameters A through D.

While I have managed to interpolate within a single Ratio group, my challenge arises when attempting to interpolate for a ratio value that falls outside these defined groups, such as 3.5. Attached is my Mathcad Prime 7 worksheet for reference. I appreciate any assistance you can provide.

Note: When the delta input "δ" exceeds the highest Delta value in a given Ratio group, the output should correspond to the highest Delta record's values, as extrapolation beyond this point is not allowed.

1_BilinearInterpolation.zip

Best answer by ttokoro

Attach it.

linterp_2D function is made by Werner_E.

L

LucMeekes

23-Emerald IV

Your dataset is somewhat uneven. You don't have values for Ratio=0.5 and Delta=45, nor for Ratio=2 or 4 and Delta=100.

Is that purposely?

Luc

P

Perez

Author

14-Alexandrite

Hello @LucMeekes , I have updated the record for a Ratio of 0.5 with Delta=45 instead of 100. All other data remains accurate. For a Ratio of 0.25 alone, there are 4 Delta rows, while the other Ratios have 3 Delta rows each.

Additionally, I've attached the updated worksheet in the Prime 9 version with a solution that I managed to implement using a brute force method. It is functioning as expected, despite being a brute force approach.