| Re: how read a file of complex? [message #10628] |
Sat, 03 January 1998 00:00 |
davidf
Messages: 2866
Registered: September 1996
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Senior Member |
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Nando Iavarone (iavarone@axpba0.ba.infn.it) writes:
> David Fanning ha scritto:
>
>> OpenR, lun, filename, /Get_Lun
>> ReadU, lun, data
>> Free_Lun, data
> Free_Lun, data ??
> Free_Lun, lun
I took a few days off to ski and try to forget that I had
ever heard of IDL. I was apparently successful. :-)
Cheers,
David
-----------------------------------------------------------
David Fanning, Ph.D.
Fanning Software Consulting
E-Mail: davidf@dfanning.com
Phone: 970-221-0438
Coyote's Guide to IDL Programming: http://www.dfanning.com/
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| Re: how read a file of complex? [message #10629 is a reply to message #10628] |
Sat, 03 January 1998 00:00  |
Ferdinando Iavarone
Messages: 10
Registered: October 1997
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Junior Member |
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David Fanning ha scritto:
> OpenR, lun, filename, /Get_Lun
> ReadU, lun, data
> Free_Lun, data
>
Thank's David.
Free_Lun, data ??
Free_Lun, lun
Cheers,
Nando
--
Nando Iavarone
Laureando Gruppo Telerilevamento
Dipartimento Interateneo di Fisica
Via Amendola, 173
70126 BARI
ITALY
Tel.: +39 80 5443166
Fax.: +39 80 5443165
e_mail: iavarone@axpba0.ba.infn.it
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| Re: how read a file of complex? [message #10630 is a reply to message #10628] |
Fri, 02 January 1998 00:00 |
davidf
Messages: 2866
Registered: September 1996
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Senior Member |
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Nando Iavarone (iavarone@axpba0.ba.infn.it) provides the
first interesting problem of the New Year when he writes:
> I have a data-file containing a matrix. Each element of matrix has the
> form(real part, imaginary part)[1] with each one LONG.
>
> 1) How create a matrix with structure [1] to read in a single pass the
> file?
> [Slow code clipped.]
For an m-by-n matrix of real-imaginary pairs of long integers,
how about something like this:
FUNCTION Read_It, filename, m, n
; Read the data all at once.
data = LonArr(m*n*2)
OpenR, lun, filename, /Get_Lun
ReadU, lun, data
Free_Lun, data
; Reform to align real data in column next to imaginary data.
colData = Reform(data, 2, m*n)
; Create vectors of real and imaginary values.
real = Reform(colData[0,*])
imag = Reform(colData[1,*])
; Make complex numbers out of real and imaginary parts.
complexData = Complex(real, imag)
; Reformat the complex data into a matrix and return.
RETURN, Reform(complexData, m, n)
END
Call this function like this:
myData = Read_It('mydata.dat', 300, 500)
I've taken more steps then necessary here (as someone is
sure to point out), but I tried to give you the sense of
how this might be done by taking advantage of IDL's array
operations instead of loops.
Cheers,
David
-----------------------------------------------------------
David Fanning, Ph.D.
Fanning Software Consulting
E-Mail: davidf@dfanning.com
Phone: 970-221-0438
Coyote's Guide to IDL Programming: http://www.dfanning.com/
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