optimize and if statement

I am running code that runs through a loop millions of times. I am trying to make the loop as effect as possible. The loop cannot be arrayed as future values depend on previous values. I used the profiler to see what was taking the most time in the loop. The line that is taking the the most time is an if statement:

if abs((a-b)/b) <.000001

Is there any way to speed this line up? change in the structure of the if or change in the way the condition is evaluated?

Answer 1

[Walter Roberson]

if b * 0.999999 < a & a < b * 1.000001

better recheck as it is pretty late at night for me.

[Victor]

Thanks for the reply. I tried your suggestion and it appears to take longer.

Answer 2

[David Sanchez]

You can try with different combinations like:

if abs((a-b)/b)*10^6 <1
if -1<(a-b)*10^6/b && (a-b)*10^6/b <1
if -.000001<(a-b)/b && (a-b)/b <.000001
if abs((a-b)/b) <1/1000000
if -b<(a-b)*10^6 && (a-b)*10^6 <b

but the time taken to check the condition is very similar in all of them. I think you can't hardly improve much the speed of that line.