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3 | <title>Batch processing tutorial</title> |
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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 | quotients.append(scan.auto_quotient()) # add this quotient to the vector |
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91 | </pre></div> |
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92 | Let's have a look at the vector, and subtract a baseline |
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93 | <div class=code><pre> |
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94 | for q in quotients: |
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95 | print q |
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96 | q.auto_poly_baseline(order=1,insitu=True) |
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97 | </pre></div> |
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98 | Now we average the lot together: |
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99 | <div class=code><pre> |
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100 | av = average_time(quotients) |
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101 | </pre></div> |
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102 | |
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103 | </div> |
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104 | <h1 class=custom> |
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105 | Appendix |
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106 | </h1> |
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107 | <div class=main align=center> |
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108 | More info can be found on the ASAP homepage |
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109 | <a href="http://www.atnf.csiro.au/computing/software/asap"> |
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110 | http://www.atnf.csiro.au/computing/software/asap</a> |
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111 | </div> |
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112 | </body> |
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113 | </html> |
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