block solver fails for BaseFixedSizeEdge with 3 vertices

[atuldivekar]

I implemented a BaseTernaryEdge derived from BaseFixedSizeEdge with 3 vertices instead of 2. (Similar to BaseBinaryEdge implementation, just 3 vertices)

I tried to solve it with block_solver.hpp, get an error in buildStructure():

schurMatrixLookup->addBlock(i1, i2); assert(c < (int)_blockCols.size() && "accessing column which is not available");

The error is because the 2nd and 3rd kinds of vertices are all treated as landmarks. but the loop that calls schurMatrixLookup->addBlock(i1, i2) does not recognize this.

For each marginalized v consider attached vertex pairs v1,v2 (could be on same or different edges attached to v) with binary edge, v1,v2 will be non-marginalized i.e. hessianIndex will be < numPoses with ternary edge, v1,v2 could be marginalized i.e. hessianIndex could be >= numPoses -- this causes the error..

Or is the block_solver not the correct way to use the Ternary Edge?

I see the example sclam_odom_laser.cpp which uses BaseFixedSizeEdge but I am not sure how that optimizer works.

[RainerKuemmerle]

Did you try with a variable sized solver instead? Which vertices of your edge are landmarks?

[RainerKuemmerle]

Duplicates #597