Hide keyboard shortcuts

Hot-keys on this page

r m x p   toggle line displays

j k   next/prev highlighted chunk

0   (zero) top of page

1   (one) first highlighted chunk

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

32

33

34

35

36

37

38

39

40

41

42

43

44

45

46

47

48

49

50

51

52

53

54

55

56

57

58

59

60

61

62

63

# LSST Data Management System 

# Copyright 2016 AURA/LSST. 

# 

# This product includes software developed by the 

# LSST Project (http://www.lsst.org/). 

# 

# This program is free software: you can redistribute it and/or modify 

# it under the terms of the GNU General Public License as published by 

# the Free Software Foundation, either version 3 of the License, or 

# (at your option) any later version. 

# 

# This program is distributed in the hope that it will be useful, 

# but WITHOUT ANY WARRANTY; without even the implied warranty of 

# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 

# GNU General Public License for more details. 

# 

# You should have received a copy of the LSST License Statement and 

# the GNU General Public License along with this program. If not, 

# see <https://www.lsstcorp.org/LegalNotices/>. 

 

 

import numpy as np 

import astropy.units as u 

 

from lsst.verify import Measurement, Datum 

 

 

def measurePA2(metric, pa1, pf1_thresh): 

"""Measurement of PA2: millimag from median RMS (see PA1) of which 

PF1 of the samples can be found. 

 

Parameters 

---------- 

metric : `lsst.verify.Metric` 

A PA2 `~lsst.verify.Metric` instance. 

pa1 : `lsst.verify.Measurement` 

A PA1 measurement instance. 

pf1_thresh : `astropy.units.Quantity` 

Quantity specifying the threshold at which to calculate PA2 

 

Returns 

------- 

measurement : `lsst.verify.Measurement` 

Measurement of PA2 and associated metadata. 

 

Notes 

----- 

The LSST Science Requirements Document (LPM-17) is commonly referred 

to as the SRD. The SRD puts a limit that no more than PF1 % of difference 

will vary by more than PA2 millimag. The design, minimum, and stretch 

goals are PF1 = (10, 20, 5) % at PA2 = (15, 15, 10) millimag following 

LPM-17 as of 2011-07-06, available at http://ls.st/LPM-17. 

""" 

 

datums = {} 

datums['pf1_thresh'] = Datum(quantity=pf1_thresh, description="Threshold from the PF1 specification") 

 

# Use first random sample from original PA1 measurement 

magDiffs = pa1.extras['magDiff'].quantity[0, :] 

 

pf1Percentile = 100.*u.percent - pf1_thresh 

return Measurement(metric, np.percentile(np.abs(magDiffs.value), pf1Percentile.value) * magDiffs.unit, 

extras=datums)