| Re: Replicate array over columns - using transpose? [message #79680] |
Fri, 23 March 2012 05:06 |
Yngvar Larsen
Messages: 134
Registered: January 2010
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Senior Member |
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I don't think this variant is covered yet:
a = reform(float([10,35,60,85,110]), 1, 5, /overwrite)
print, rebin(a, 4, 5)
--
Yngvar
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| Re: Replicate array over columns - using transpose? [message #79693 is a reply to message #79680] |
Thu, 22 March 2012 08:18  |
Russell[1]
Messages: 101
Registered: August 2011
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Senior Member |
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On Mar 22, 8:01 am, Craig Markwardt <craig.markwa...@gmail.com> wrote:
> On Thursday, March 22, 2012 6:11:54 AM UTC-4, robintw wrote:
>> Hi all,
>
>> I've got an array, a, as follows:
>
>> IDL> print, a
>> 10.0000 35.0000 60.0000 85.0000 110.000
>
>> I want to replicate this across 4 columns to produce an array like the
>> following:
>
>> 10 10 10 10
>> 35 35 35 35
>> 60 60 60 60
>> 85 85 85 85
>> 110 110 110 110
>
>> I'm using the CMREPLICATE routine to do this, and get the following:
>
>> IDL> print, CMREPLICATE(a, 4)
>> 10.0000 35.0000 60.0000 85.0000 110.000
>> 10.0000 35.0000 60.0000 85.0000 110.000
>> 10.0000 35.0000 60.0000 85.0000 110.000
>> 10.0000 35.0000 60.0000 85.0000 110.000
>
>> However, I want to replicate it in the columns as in the example above.
>> As far as I can see it there are two ways to deal with this: transpose
>> the array after I've done it (computationally expensive, as I'll be
>> doing it with far larger arrays in the real program) or transpose it
>> before running CMREPLICATE. However, if I do this I get an extra
>> dimension added:
>
>> IDL> help, CMREPLICATE(transpose(a), 4)
>> <Expression> FLOAT = Array[1, 5, 4]
>
>> Is there a way to replicate over the columns without adding this extra
>> dimension? I'm sure I'm missing something simple here.
>
> I'm the CM in CMreplicate, but I wouldn't use CMreplicate. I use this instead.
>
> print, [1,1,1,1,1] # a
>
> Usually I'm matching up X and Y labels to a 2D grid, so I do this,
>
> XX = (X*0 + 1) # Y
> YY = X # (Y*0 + 1)
>
> Now XX and YY are 2D arrays with X running along one axis and Y running along the other axis. It looks crazy, but it works.
>
> Craig
Ha! I should have read on. I didn't see someone posted this answer.
Sorry for the repetition,
Russell
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| Re: Replicate array over columns - using transpose? [message #79694 is a reply to message #79693] |
Thu, 22 March 2012 08:17 |
Russell[1]
Messages: 101
Registered: August 2011
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Senior Member |
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It's way easier than that.
Suppose,
a=[10,35,60,85,110.]
and you want it to have n entries, then all you need is
b=(1+bytarr(n))#a
voila!
Russell
On Mar 22, 6:11 am, Robin Wilson <ro...@rtwilson.com> wrote:
> Hi all,
>
> I've got an array, a, as follows:
>
> IDL> print, a
> 10.0000 35.0000 60.0000 85.0000 110.000
>
> I want to replicate this across 4 columns to produce an array like the
> following:
>
> 10 10 10 10
> 35 35 35 35
> 60 60 60 60
> 85 85 85 85
> 110 110 110 110
>
> I'm using the CMREPLICATE routine to do this, and get the following:
>
> IDL> print, CMREPLICATE(a, 4)
> 10.0000 35.0000 60.0000 85.0000 110.000
> 10.0000 35.0000 60.0000 85.0000 110.000
> 10.0000 35.0000 60.0000 85.0000 110.000
> 10.0000 35.0000 60.0000 85.0000 110.000
>
> However, I want to replicate it in the columns as in the example above.
> As far as I can see it there are two ways to deal with this: transpose
> the array after I've done it (computationally expensive, as I'll be
> doing it with far larger arrays in the real program) or transpose it
> before running CMREPLICATE. However, if I do this I get an extra
> dimension added:
>
> IDL> help, CMREPLICATE(transpose(a), 4)
> <Expression> FLOAT = Array[1, 5, 4]
>
> Is there a way to replicate over the columns without adding this extra
> dimension? I'm sure I'm missing something simple here.
>
> Cheers,
>
> Robin
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| Re: Replicate array over columns - using transpose? [message #79695 is a reply to message #79694] |
Thu, 22 March 2012 05:01 |
Craig Markwardt
Messages: 1869
Registered: November 1996
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Senior Member |
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On Thursday, March 22, 2012 6:11:54 AM UTC-4, robintw wrote:
> Hi all,
>
> I've got an array, a, as follows:
>
> IDL> print, a
> 10.0000 35.0000 60.0000 85.0000 110.000
>
> I want to replicate this across 4 columns to produce an array like the
> following:
>
> 10 10 10 10
> 35 35 35 35
> 60 60 60 60
> 85 85 85 85
> 110 110 110 110
>
> I'm using the CMREPLICATE routine to do this, and get the following:
>
> IDL> print, CMREPLICATE(a, 4)
> 10.0000 35.0000 60.0000 85.0000 110.000
> 10.0000 35.0000 60.0000 85.0000 110.000
> 10.0000 35.0000 60.0000 85.0000 110.000
> 10.0000 35.0000 60.0000 85.0000 110.000
>
> However, I want to replicate it in the columns as in the example above.
> As far as I can see it there are two ways to deal with this: transpose
> the array after I've done it (computationally expensive, as I'll be
> doing it with far larger arrays in the real program) or transpose it
> before running CMREPLICATE. However, if I do this I get an extra
> dimension added:
>
> IDL> help, CMREPLICATE(transpose(a), 4)
> <Expression> FLOAT = Array[1, 5, 4]
>
> Is there a way to replicate over the columns without adding this extra
> dimension? I'm sure I'm missing something simple here.
I'm the CM in CMreplicate, but I wouldn't use CMreplicate. I use this instead.
print, [1,1,1,1,1] # a
Usually I'm matching up X and Y labels to a 2D grid, so I do this,
XX = (X*0 + 1) # Y
YY = X # (Y*0 + 1)
Now XX and YY are 2D arrays with X running along one axis and Y running along the other axis. It looks crazy, but it works.
Craig
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| Re: Replicate array over columns - using transpose? [message #79696 is a reply to message #79695] |
Thu, 22 March 2012 04:42 |
Heinz Stege
Messages: 189
Registered: January 2003
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Senior Member |
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On Thu, 22 Mar 2012 12:25:52 +0100, Heinz Stege wrote:
>
> help,transpose(rebin(a,n_elements(a),4,/sample))
Don't use the above. Lajos' solution without the TRANSPOSE operation
is much more efficient:
On Thu, 22 Mar 2012 03:50:39 -0700 (PDT), Lajos Foldy wrote:
>
> b=rebin(reform(a,1,5), 5,5)
Heinz
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| Re: Replicate array over columns - using transpose? [message #79698 is a reply to message #79697] |
Thu, 22 March 2012 03:57 |
dplatten
Messages: 32
Registered: December 2007
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Member |
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Hi Robin,
You can use a combination of REBIN and TRANSPOSE to do this. The following should work for you:
nElements = 5
nCols = 4
test = INDGEN(nElements)
print, test
0 1 2 3 4
print, REBIN(TRANSPOSE(test), nCols, nElements)
0 0 0 0
1 1 1 1
2 2 2 2
3 3 3 3
4 4 4 4
Regards,
David
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| Re: Replicate array over columns - using transpose? [message #79699 is a reply to message #79698] |
Thu, 22 March 2012 03:50 |
Lajos Foldy
Messages: 176
Registered: December 2011
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Senior Member |
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On Mar 22, 11:11 am, Robin Wilson <ro...@rtwilson.com> wrote:
> Hi all,
>
> I've got an array, a, as follows:
>
> IDL> print, a
> 10.0000 35.0000 60.0000 85.0000 110.000
>
> I want to replicate this across 4 columns to produce an array like the
> following:
>
> 10 10 10 10
> 35 35 35 35
> 60 60 60 60
> 85 85 85 85
> 110 110 110 110
>
> I'm using the CMREPLICATE routine to do this, and get the following:
>
> IDL> print, CMREPLICATE(a, 4)
> 10.0000 35.0000 60.0000 85.0000 110.000
> 10.0000 35.0000 60.0000 85.0000 110.000
> 10.0000 35.0000 60.0000 85.0000 110.000
> 10.0000 35.0000 60.0000 85.0000 110.000
>
> However, I want to replicate it in the columns as in the example above.
> As far as I can see it there are two ways to deal with this: transpose
> the array after I've done it (computationally expensive, as I'll be
> doing it with far larger arrays in the real program) or transpose it
> before running CMREPLICATE. However, if I do this I get an extra
> dimension added:
>
> IDL> help, CMREPLICATE(transpose(a), 4)
> <Expression> FLOAT = Array[1, 5, 4]
>
> Is there a way to replicate over the columns without adding this extra
> dimension? I'm sure I'm missing something simple here.
>
> Cheers,
>
> Robin
b=rebin(reform(a,1,5), 5,5)
regards,
Lajos
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