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| 2 | <head> |
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| 3 | <title>Batch processing tutorial</title> |
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| 6 | background-color: #dbfff9; |
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| 26 | </style> |
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| 27 | </head> |
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| 28 | <body> |
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| 29 | <div> |
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| 30 | <h1 class=custom> |
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| 31 | Introduction |
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| 32 | </h1> |
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| 33 | <div class=main align=center> |
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| 34 | This tutorial is aimed at observers who want to "batch reduce" their |
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| 35 | data, i.e. process multiple files the same way. |
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| 36 | </div> |
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| 37 | <h1 class=custom> |
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| 38 | Part I - Need to knows |
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| 39 | </h1> |
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| 40 | <div class=main align=center> |
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| 41 | As ASAP is python based, we need to know a few commands and expression. |
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| 42 | Python has "lists", which are basically vectors. We will use |
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| 43 | these extensively.<br> |
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| 44 | <div class=code><pre> |
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| 45 | x = range(5) # creates a vector of length 5, x = [0,1,2,3,4] |
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| 46 | len(x) # gives the length of the vector |
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| 47 | x[0] # gets the first element of the vector |
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| 48 | x[-1] # gets the last element of the vector |
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| 49 | </pre></div> |
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| 50 | "for" loops are very useful. The code which should be run in the loop |
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| 51 | has to be indented. The end of the loop is indicated by the fact that |
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| 52 | the next command is aligned with the for.<br> |
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| 53 | The following code prints out the numbers [0..4] |
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| 54 | <div class=code><pre> |
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| 55 | for i in range(5): |
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| 56 | print i |
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| 57 | </pre></div> |
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| 58 | Vectors can also be filled: |
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| 59 | <div class=code><pre> |
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| 60 | x = [] # empty |
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| 61 | for i in range(5): |
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| 62 | x.append(i*5) |
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| 63 | </pre></div> |
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| 64 | The output is x = [0,5,10,15,20]<br> |
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| 65 | Now we can access those elements like we did above (by index), or directly: |
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| 66 | <div class=code><pre> |
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| 67 | for i in x: |
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| 68 | print i |
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| 69 | </pre></div> |
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| 70 | That's all we need to know! |
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| 71 | |
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| 72 | </div> |
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| 73 | <h1 class=custom> |
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| 74 | Part II - the code |
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| 75 | </h1> |
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| 76 | <div class=main align=center> |
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| 77 | This shows example code to process multiple files.<p> |
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| 78 | Let's say we have three files (a.rpf, b.rpf, c.rpf) which contain |
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| 79 | on/off pairs and we want to get the quotients<br> |
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| 80 | <div class=code><pre> |
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| 81 | fnames = ["a.rpf","b.rpf","c.rpf"] # First we set up a vector of filenames |
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| 82 | vec = [] # a vector to hold the scantables |
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| 83 | for f in fnames: |
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| 84 | vec.append(scantable(f)) # fill the vector with scantables |
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| 85 | </pre></div> |
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| 86 | Then we can loop over all scantables: |
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| 87 | <div class=code><pre> |
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| 88 | quotients = [] # to hold the quotient scantables |
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| 89 | for scan in vec: # loop over input scantables |
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| 90 | on = scan.get_source("*_S") |
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| 91 | off = scan.get_source("*_R") |
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| 92 | quotients.append(quotient(on,off)) # add this quotient to the vector |
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| 93 | </pre></div> |
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| 94 | Let's have a look at the vector, and subtract a baseline |
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| 95 | <div class=code><pre> |
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| 96 | for q in quotients: |
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| 97 | print q |
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| 98 | q.auto_poly_baseline(order=1,insitu=True) |
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| 99 | </pre></div> |
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| 100 | Now we average the lot together: |
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| 101 | <div class=code><pre> |
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| 102 | av = average_time(quotients) |
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| 103 | </pre></div> |
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| 104 | |
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| 105 | </div> |
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| 106 | <h1 class=custom> |
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| 107 | Appendix |
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| 108 | </h1> |
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| 109 | <div class=main align=center> |
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| 110 | More info can be found on the ASAP homepage |
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| 111 | <a href="http://www.atnf.csiro.au/computing/software/asap"> |
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| 112 | http://www.atnf.csiro.au/computing/software/asap</a> |
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| 113 | </div> |
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| 114 | </body> |
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| 115 | </html> |
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