[SOLVED] Using erf function on shell script

Issue

I am trying to calculate some variables inside awk and most are going well. The single not working is when I try to use erf:

| awk '{print $1, $2, $3, $4, $5, $6, (1365*(erf(6/(2*(1/2)*((1/1250000)*$6*10*10*10*10*10*10*365)))))} ' 

Does someone know how to help in this trouble?

best, Guilherme

Solution

You can do a virtually 1-1 conversion to Perl:

| perl -MPOSIX=erf -ale 'print join " ", @F[0,1,2,3,4,5],
  1365*(erf(6/(2*(1/2)*((1/1250000)*$F[5]*1e6*365)))))'

• -a tells Perl to autosplit lines into array @F
• -l makes Perl add newline after printing
• Perl arrays are indexed from 0 (awk indexes fields from 1) so awk $3 becomes Perl $F[2]
• @F[0,1,2,3,4,5] is a list of $F[0], $F[1], ...
• join converts a list into a string using the separator provided. I used this as it seemed a bit neater than typing: print $F[0], " ", $F[1], " ", $F[2], " ", ...

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Although it has been removed in more recent versions of Perl, older versions have a helper program a2p to help with translation from awk (and a similar s2p for sed).

Answered By - jhnc

Answer Checked By - Katrina (WPSolving Volunteer)