Bug in search_indices on Moi curvilinear Grid

[erikvansebille]

Somewhere in the last few weeks, we introduced a bug into the index searching for Parcels v4. This is apparent in the https://github.com/OceanParcels/parcels-benchmarks/pull/7 script, which used to give correct results at the assert statement at the end, but not anymore...

I explored this further by setting the runtime to 1 hour and printing out the xi, xis, yi, and eta`

I get on Parcels v3:

X: 3324, 0.5, Y: 1115, 0.8248433741309578 at 0.0
X: 3324, 0.5, Y: 1115, 0.8248433741309578 at 0.0
X: 3324, 0.5006179762422467, Y: 1115, 0.8396468317957123 at 900.0
X: 3324, 0.5006179762422467, Y: 1115, 0.8396468317957123 at 900.0
X: 3324, 0.5006179762422467, Y: 1115, 0.8396468317957123 at 900.0
X: 3324, 0.5006179762422467, Y: 1115, 0.8396468317957123 at 900.0
X: 3324, 0.501144400448605, Y: 1115, 0.8545824631896164 at 1800.0
X: 3324, 0.501144400448605, Y: 1115, 0.8545824631896164 at 1800.0
X: 3324, 0.501144400448605, Y: 1115, 0.8545824631896164 at 1800.0
X: 3324, 0.501144400448605, Y: 1115, 0.8545824631896164 at 1800.0
X: 3324, 0.5015907166235609, Y: 1115, 0.8696238335668403 at 2700.0
X: 3324, 0.5015907166235609, Y: 1115, 0.8696238335668403 at 2700.0
X: 3324, 0.5015907166235609, Y: 1115, 0.8696238335668403 at 2700.0
X: 3324, 0.5015907166235609, Y: 1115, 0.8696238335668403 at 2700.0

But I get on Parcels v4:

X: 3324, 0.5, Y: 1115, 0.8248433470726013 at 2010-01-01T12:00:00.000000000
X: 3324, 0.5, Y: 1115, 0.8248433470726013 at 2010-01-01T12:00:00.000000000
X: 3324, 0.5006179809570312, Y: 1115, 0.8396468162536621 at 2010-01-01T12:15:00.000000000
X: 3324, 0.5006179809570312, Y: 1115, 0.8396468162536621 at 2010-01-01T12:15:00.000000000
X: 1284, 0.5277839303016663, Y: 1115, 0.8545824885368347 at 2010-01-01T12:30:00.000000000  # <- This is unexpected
X: 1284, 0.5277839303016663, Y: 1115, 0.8545824885368347 at 2010-01-01T12:30:00.000000000
X: 3324, 0.48893365263938904, Y: 1115, 0.8279098272323608 at 2010-01-01T12:45:00.000000000
X: 3324, 0.48893365263938904, Y: 1115, 0.8279098272323608 at 2010-01-01T12:45:00.000000000

Check the sudden jump to X: 1284 on the 5th line of the Parcels v4 output. This is clearly wrong. I'll have to find out what's happening here

[fluidnumerics-joe]

That's odd. It even goes back to 3324 index later on

[erikvansebille]

OK, turned out not to be a bug; but instead a missing mesh="spherical" in the grid creation