Atan2 function in awk

Shell Programming and Scripting
1

Hello All,

I need your help in the following situation. I have a 100x100 matrix with angle values ranging from -180 to 180. I would like to calculate the atan2 values for the above mentioned matrix, and the output should be in the same format (100x100 matrix).

I tried the following code:

awk '{for(i=1; i<=NF; i++) {s=s FS atan2($i)} print s;s=""}' input > output

But, I got the following error:

^1 is invalid as number of arguments for atan2

Could anyone help me in this regard? Expecting your replies and thanks in advance.

Warm regards
Fredrick.

2

atan requires two arguments.

atan2(y, x)
  This gives you the arctangent of y / x in radians.
3

Hi Scott,

Thanks for your reply. As I am having my input as angles in the range of -180 to 180 in degrees, how can I convert this angle in to x and y? Since atan2() function will be taken in the form of atan2(y,x) or other forms with x and y.

So could you help me in this regard. Thanks in advance.

Warm regards
Fredrick.

4

You are on the wrong track. atan is the arctangens. For angles, you can calculate tan (alpha). atan is the inverse, yielding an angle as a result.

Go back to high school maths: tan (alpha) = sin (alpha) / cos (alpha).