2019-03-13

TESS CPM; inducing points

NASA TESS proposals are due tomorrow! I spent most of my morning writing with Tyler Pritchard (NYU), who has written almost all of our proposal to perform image differencing and produce transient-alert light curves with TESS. I worked on the descriptions of the philosophy and characteristics of the CPM model, which delivers very good performance in TESS-like situations (think K2 and Kepler). Not everything I have written is going to survive, though, because the proposal strict page limit is 4 pages (and a 800-character abstract, which is very hard!).

Late in the day I had a good conversation with Lauren Anderson (NYU) about how inducing points can be used to lower the rank of the linear-algebra operators with Anderson. We talked it out, about how with the control points your matrix can only have a rank as large as the control-point set, and (even better) the control points can be placed in the space to create symmetries that speed computation. But I had an epiphany during the conversation, which is Duh in retrospect: The low-rank approximation is an approximation to the information tensor not the covariance matrix. (These are just inverses of each other.)

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