Re: Procedure for percent of a value
- From: claird@xxxxxxxxx (Cameron Laird)
- Date: Fri, 29 Feb 2008 17:18:36 +0000
In article <47c8207c$1_4@xxxxxxxxxxxxxxx>,
Simon Bachmann <ssiimmoonnbbaacchhmmaannnn@xxxxxxxxxxxxxxxxxxx> wrote:
Marcos Martinez Sancho wrote:.
Hello,
I need a small procedure for calculate the percent of a value
e.g.
set srate [expr int(($tps_ok / $number_of_total_tps)*100)]
puts "\nTEST RESULT: $number_of_total_tps tps of which $tps_ok PASSED and
$tps_nok FAILED so $srate % succes rate"
doesnt look optimal and is not working except when srate = 100%. Otherwise,
I get 0%.
When both numbers in a division operation are are integer, [expr]
performs an integer division. That means that only the integer part of
the result is calculated, no "comma part":
% expr 10/3
3
%
And since srate < 100% means that tps_ok is less than
number_of_total_tps, the $tps_ok / $number_of_total_tps will always give
0 as result.
The solution is to make one of the values a floating point value, all
other numbers will be "coerced" into floating point numbers too. Usually
it's done like this:
set srate [expr int((1.0 * $tps_ok / $number_of_total_tps)*100)]
.
.
'Everybody understand that floating point calculations are NOT
required? Depending on the domains of the variables, it might
well be advantageous to write
expr (100 * $tps_ok) / $number_of_total_tps
or
expr ((200 * $tps_ok) + 1) / (2 * $number_of_total_tps)
or several other variations.
Computer arithmetic's harder'n it looks--but not impossible.
.
- References:
- Procedure for percent of a value
- From: Marcos Martinez Sancho
- Re: Procedure for percent of a value
- From: Simon Bachmann
- Procedure for percent of a value
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