Function lsst::meas::base::makeShapeTransformMatrix¶

Function Documentation¶

ShapeTrMatrix lsst::meas::base::makeShapeTransformMatrix(geom::LinearTransform const &xform)¶

Construct a matrix suitable for transforming second moments.

Given an LinearTransform which maps from positions (x, y) to (a, d), returns a 3-by-3 matrix which transforms (xx, yy, xy) to (aa, dd, ad).

That is, given an input transform described by the matrix

| A11 | A12 | | A21 | A22 |

we return the matrix

| A11*A11 | A12*A12 | 2*A11*A12 | | A21*A21 | A22*A22 | 2*A21*A22 | | A11*A21 | A12*A22 | A11*A22 + A12*A21 |

Return

A 3-by-3 transformation matrix for the second order moments

Parameters