https://pfspipe.ipmu.jp/jira This file is an XML representation of an issue en-us 8.3.4 803005 13-09-2019 https://pfspipe.ipmu.jp/jira/browse/PIPE2D-799 DRP 2-D Pipeline <p>We need to correct for the Jacobian when resampling the wavelengths.<br/> It would also be helpful to have a function that will provide the dispersion given a position/wavelength.</p> PIPE2D-799

Correct for Jacobian when resampling

Story Normal Done Done price price Fri, 26 Mar 2021 19:24:59 +0000 Wed, 30 Mar 2022 23:45:30 +0000 Mon, 10 Jan 2022 18:02:45 +0000 0 3 <p>At the same time please support vector-valued dispersion values in <tt>DetectorMap</tt> (which will probably be needed anyway). The code can be as simple as this, but it needs to be a method. If we know more about the insides of the map we should be able to do better.</p> <div class="code panel" style="border-width: 1px;"><div class="codeContent panelContent"> <pre class="code-python"> <span class="code-keyword">def</span> getDispersion(detectorMap, fiberId, wavelength, dwavelength=0.1): """Return the dispersion <span class="code-keyword">in</span> nm/pixel detectorMap: DetectorMap fiberId: `<span class="code-object">int</span>` The fiber whose dispersion <span class="code-keyword">is</span> desired wavelength: `<span class="code-object">float</span>` <span class="code-keyword">or</span> iterable <span class="code-keyword">or</span> `<span class="code-object">float</span>` Wavelengths where the dispersion <span class="code-keyword">is</span> desired dwavelength: `<span class="code-object">float</span>` Interval to use <span class="code-keyword">for</span> finite differencing to determine the dispersion """ wavelength = np.atleast_1d(wavelength) l0 = detectorMap.findPoint(fiberId, wavelength - 0.5*dwavelength)[:, 1] l1 = detectorMap.findPoint(fiberId, wavelength + 0.5*dwavelength)[:, 1] dispersion = dwavelength/(l1 - l0) <span class="code-keyword">return</span> dispersion </pre> </div></div> <p>pfsMerged now has units of summed counts per resampled pixel.</p> <p>Before: <span class="image-wrap" style=""><img src="https://pfspipe.ipmu.jp/jira/secure/attachment/15058/15058_noJacobian.png" style="border: 0px solid black" /></span></p> <p>After: <span class="image-wrap" style=""><img src="https://pfspipe.ipmu.jp/jira/secure/attachment/15057/15057_yesJacobian.png" style="border: 0px solid black" /></span></p> <p>A demonstration that the units of the <tt>pfsMerged</tt> is summed counts per resampled pixel:</p> <p>At 637.4 nm:<br/> Blue: 43411.88548364646 counts, dispersion 0.06598235465315838 nm/pixel<br/> Red: 42618.45107528691 counts, dispersion 0.08778364248382786 nm/pixel<br/> Merged: 93027.31531262455 counts, dispersion 0.08087158203125 nm/pixel<br/> Note that (blue flux)/(blue dispersion) + (red flux)/(red dispersion) = (merged flux)/(merged dispersion)<br/> (The error is &lt; 1%. I’m guessing it’s not exact because there’s some variance weighting going on.)</p> <p>Changes look fine to me.</p> <p>Merged.</p> Relates INSTRM-1470 PIPE2D-1008 Development Rank 0|zzs5b5:zzzzzy Reviewers hassan Sprint 2DDRP-2021 A 10 2DDRP-2021 A12 Story Points 2.0