Arrays

[vrk]

Hi

I am having a doubt in arrays,

I got a column array around 200 index,of this i got some negative values.for ex: from 0 to 20 the values are positive ,from 21 to 40 the values are positive,it continues likewise positive and negative.

For this i have to change the negative sign and add some common value to each of the negative values. so that i can get all positive values in arrays

thanks

[jon_mcbee]

If I understand you correctly, you could just use the absolute value node on your array (see attached).  It I dont understand you correctly please let me know so that I can help.

Good Luck

[NIquist]

You're not giving us much information to help you.  Take a look at this to get some simple ideas:

[NIquist]

You beat me to the punch.  But mine has graphs! 

[jon_mcbee]

What is the old saying, "A graph in time saves nine..."

[NIquist]

Now that I think about it, I hope the original question wasn't an April Fool's joke!

[vrk]

Thanks evryone, no its not April fool joke. Its a part of my program

I will check it and let u all know the result

thanks

[altenbach]

I think easiest would be to subtract the ArrayMin. This will change the offset so the lowest point of the array is zero. At the same time it is not changing the shape of the curve or introduce discontinuities.

Modify as needed. (You could e.g. add a case so it only subtracts if the ArrayMin is negative.)

Message Edited by altenbach on 04-01-2008 05:54 PM

[vrk]

Hi

Thanks for your codes

Let us consider the code AbsValArray.vi, initially we have the sine wave, with  the absolute block all the negative values are changed to positive values but i need those values to be linearly increase with time(to compensate the negative phase angle we can add 90 deg)

[altenbach]

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vrk wrote:

... but i need those values to be linearly increase with time(to compensate the negative phase angle we can add 90 deg)

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Sorry, I don't understand what you are saying. What "values"? Where is a "negative phase angle"? What exactly "increases linearly"?

Using the "absolute value" you are highly distorting the signal, for example if you would do a Fourier transform before and after, you would see that taking the absolute value doubles the frequency, adds additional harmonics, and (of course) adds a DC component. It seems silly to do all that to a signal unless you're not really interested in the data at all. What good is irreversibly mutilating the data? If this is acceptable, you might as well multiply your array with zero to make sure nothing is negative. 😮 same difference! 😄

Why don't you show us some of your real data and tell us what you want. (e.g. before>>after).