Struct lsst::afw::math::detail::TrapezoidalPacker

struct TrapezoidalPacker

A helper class ChebyshevBoundedField, for mapping trapezoidal matrices to 1-d arrays.

This class is not Swigged, and should not be included by any other .h files (including lsst/afw/math/detail.h); it’s for internal use by ChebyshevBoundedField only, and it’s only in a header file instead of that .cc file only so it can be unit tested.

We characterize the matrices by their number of columns (nx) and rows (ny), and the number of complete rows minus one (m).

This splits up the matrix into a rectangular part, in which the number of columns is the same for each row, and a wide trapezoidal or triangular part, in which the number of columns decreases by one for each row.

Here are some examples of how this class handles different kinds of matrices:

A wide trapezoidal matrix with orderX=4, orderY=3: nx=5, ny=4, m=0

0 1 2 3 4 5 6 7 8 9 10 11 12 13

A tall trapezoidal matrix with orderX=2, orderY=4 nx=3, ny=5, m=2

0 1 2 3 4 5 6 7 8 9 10 11

A triangular matrix with orderX=3, orderY=3 nx=4, ny=5, m=0

0 1 2 3 4 5 6 7 8 9

A wide rectangular matrix with orderX=3, orderY=2 nx=4, ny=3, m=3

0 1 2 3 4 5 6 7 8 9 10 11

A tall rectangular matrix with orderX=2, orderY=3 nx=3, ny=4, m=4

0 1 2 3 4 5 6 7 8 9 10 11