igor vs. IDL

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Wed, 08/31/2016 - 01:46 am

I am transiting from IDL ('interactive data language', a data analysis environment common e.g. in astrophysics) to Igor. Two questions:

- Has someone compiled a dictionary of the Igor equivalents of common IDL commands?

- A very common programming technique in IDL is the creation of index arrays to produce subsets of other arrays, that fullfill a certain criterion. Adressing an IDL array with another array produces a new array, that is automatically created. My translation of this into Igor reads clumsy:

•make /i/u/n=1000 list
•list = p    // in IDL, this and the preceding statement could be cast into one
•extract /indx list, mask, list <= 500
•make /i/u/n=( numpnts( mask)) sublist
•sublist = list[ mask[p]]   // again, in IDL sublist would be created automatically
•display sublist


Is there a way to simplify?

Regards, UHe
At least you can simplify to:

make/o/i/u/n=1000 list = p
extract /indx list, mask, list <= 500
make /i/u/n=( numpnts( mask)) sublist  = list[ mask[p]]
display sublist


If you don't necessarily need the index wave, you might get away with MatrixOP depending on your subset criteria. I think the above is equivalent to

make/o/i/u/n=1000 list = p
MatrixOP/O sublist = list / greater(501,list)
WaveTransform zapInfs sublist
display sublist


but it's the same number of lines and the number type of the output changes.

August 31, 2016 at 05:42 am - Permalink

MatrixOP provides other methods for creating subsets of arrays:
MatrixOP WaveMap()
MatrixOP WaveIndexSet()

as well as the more trivial:
MatrixOP subWaveC()
MatrixOP subWaveR()
MatrixOP subRange()


A.G.

August 31, 2016 at 07:32 am - Permalink