Weblog

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

Still Testing

I finished some tests, ran them, and reported the results. I went back to coding the polynomial interpolator.

Posted on 24 Oct 2014

More Tests

I backed out the polynomial interpolation code and wrote some new tests where the input image is a grid. I've had some successful results, but still need to get some tests to run and write other tests.

Posted on 23 Oct 2014

Not Quite Yet

I wrote the first version of the code to replace linear interpolation with polynomial interpolation in map_value. I did a comparison of the old regression tests to the results from the new code. The results are not quite good enough, so I will have to do more testing.

Posted on 22 Oct 2014

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

Backtracking

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