GriddedInterpolant performance, meshgrid vs ndgrid formats

I have been using griddedInterpolant for a long time now. But, starting today, I got the following warning:

Warning: Query data is in MESHGRID format, NDGRID format will yield better performance.
Convert your query data (Xq, Yq) as follows:
   F = griddedInterpolant(. . .);
   Xq = Xq'; Yq = Yq';
   Vq = F(Xq,Yq);

I searched but have not found any discussion about this performance issue. I am hoping that someone out there can help.

Note that I am fully aware of the difference between MESHGRID and NDGRID formats. I am curious about why the NDGRID format provides an advantage.

My guess is that it has to do with column vs row operations.

Best,

Mark

[Mark Brandon]

Darova, thanks for the edit.

[Bruno Luong]

Oddly to me, this transposition

Xq = Xq'; Yq = Yq';
Vq = F(Xq,Yq)

could be done internaly by griddedInterpolant. Why throwing a warning instead of implementing the recommended fix?

Answer 1

[Matt J]

Presumably because ndgridded query data will result in the data being looped through with better memory locality.