A summary of work I've done at the Space Telescope Institute.

Approximately Right

All the results from the regression tests approximately match the previous results. However, it is an open question whether the match is good enough. Warren suggests using tweakreg as a test and I am waiting on instructions on how to do this. I did another merge from subversion to get the latest version of the code. And I started work on a higher order polynomial interpolation to get possibly more accurate results.

Posted on 21 Oct 2014

More Fixed

I found the other half of the bug I've been hunting for. All the unit tests pass. I ran the regression tests. Some things seem to work ok, but there are some issues I will need to look at more closely.

Posted on 20 Oct 2014

Half Fixed

I figured out last night that the problems with drizzlepac were caused by an off by one problem. I fixed the magnitude of the result by shifting the input pixel map, but the result is also shifted. I need to find where there needs to be a compensatory shift in the output.I also fixed a bug in the stsci.sphere documentation.

Posted on 17 Oct 2014

Test and Fail

I got the unit tests for do_driz and do_blot to run. They are close to, but do not match the old results. It looks like there is a subpixel difference in the coordinate mapping. I have edited the old C source so it produces a pixmap and I can compare the two.

Posted on 16 Oct 2014

Sturm und Drang

I got the old drizzlepac test code to run to completion and produce an output file. Naturally it did not match the result I got from the new drizzlepac code. Tomorrow I will try to figure out why.

Posted on 15 Oct 2014

A New Hope

I spent the day writing a test case that runs do_driz in the old version of drizzlepac. I am now trying to get it to run to completion -- it throws a segmentation error.

Posted on 14 Oct 2014


I spent the morning solving a link problem with the old version of drizzlepac linking with the unit tests. I spent some time trying to work with the unit tests in old drizzlepac. I came to the conclusion that the python callback object made writing true unit tests impossible. What I will have to do instead is write new tests which call tdriz and tblot for both the new and old code and reconcile the versions.

Posted on 13 Oct 2014

A New Plan

My new plan is to compare the results from the current version of drizzlepac to my new version. I spent the day modifying the code and my unit tests so they would work together. Still have got a successful link.

Posted on 10 Oct 2014

Overlap Fixed

The no overlap problem in doblot turned out to be a mixup in the x-y coordinate order plus a typo in calc_pixmap.py. So now there are no obvious errors in the output, but the output still does not match the results of the previous version of the code and I am going to have to figure out why.

Posted on 09 Oct 2014