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Double Accuracy [message #29679]

Mon, 11 March 2002 10:46

michaeltcruz
Messages: 4
Registered: March 2002

Junior Member

I am in the process of writing a program to read in exponential data
and plot its relationship to another variable. The trouble I am
having is that the values I am reading in are very small and I am
losing accuracy when I convert from a STRING to DOUBLE. Below is the
procedure I am using with a sample of the input and output. As you
can see, the output for this RATIO value is truncated to eight digits
which makes the value useless. I am fairly new to PVWAVE so I could
be making some fundamental mistakes. Appreciate help anyone can give.

PRO read_scc, file, VTCW, DOY, Year, Time, Ratio

Dummy = STRARR(4)
TempRatio = DOUBLE(1.0)

status = DC_READ_FIXED(file, Dummy, $
Format = "(7X, A33)", Nskip = 1)

VTCW = float(Dummy(0))
Year = STRMID(Dummy(1), 1, 4)
DOY = fix(STRMID(Dummy(1), 6, 3))
Time = float(STRMID(Dummy(1), 10, 33))
Ratio = Dummy(2)
print, 'BRatio', Ratio
Ratio = STRSUBST(Ratio, 'e', 'd');
print, 'ARatio', Ratio
Ratio = DOUBLE(Ratio)
info, Ratio

END

INPUT FILE

xxx ZZZZZ 02 022 07:29:11
VTCW = 5.447425871924000e+13
UTC = 2002 022 2.583419472210000e+04
RATIO = 9.999198181040011e-07

OUTPUT

;BRatio 9.999198181040011e-07
;ARatio 9.999198181040011d-07
RATIO DOUBLE = 9.9991982e-07

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[Message index]

		Double Accuracy By: michaeltcruz on Mon, 11 March 2002 10:46
		Re: Double Accuracy By: michaeltcruz on Thu, 14 March 2002 10:17
		Re: Double Accuracy By: Craig Markwardt on Tue, 12 March 2002 12:38
		Re: Double Accuracy By: michaeltcruz on Tue, 12 March 2002 11:50
		Re: Double Accuracy By: Craig Markwardt on Tue, 12 March 2002 07:55
		Re: Double Accuracy By: michaeltcruz on Tue, 12 March 2002 07:24
		Re: Double Accuracy By: David Burridge on Tue, 12 March 2002 02:01

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