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smungar1-Visitor
1-Visitor
Aug 28, 2014 2:10 PM UTC
Solved

cannot sum

Hi guys,

I want to calculate spectral moments of a wave spectrum (of ocean waves). This involves the use of the transcendental equation to obtain the wave number k by iteration. I have calculated k for a limited set of wave frequencies, see sheet. However, I would now like to sum these wave numbers, but I am unable to do this. Can anybody help?

I am new to Mathcad so maby Im just being stupid here.

MikeArmstrongAnswer
1-Visitor
Aug 28, 2014 2:49 PM UTC

How about using the summation operator?

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3 replies

MikeArmstrong1-VisitorAnswer
1-Visitor
Aug 28, 2014 2:49 PM UTC

How about using the summation operator?

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MikeArmstrong1-Visitor
1-Visitor
Aug 28, 2014 2:52 PM UTC

I forgot to add that if you are working through a spectral analysis you might be better making wave frequency a function of the wave number and so on. I have been working on exactly the same stuff recently

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Werner_E
Werner_E25-Diamond I
25-Diamond I
Aug 28, 2014 3:03 PM UTC

I see no attempt to calculate a sum in the sheet you attached.

I ssume you'd like to sum up the four results and you already tried the sum symbol and it failed, right?

The reason for this is that you had defined omega as range variable and not as vector. so the result f(omega) is NOT a vector, even if it looks like a vector.

The solution to your problem is to define omega as a vector and use the vectorization operator from the operators menu.

As you simply have just four values of omega I created the vecor manually using stack in the attached sheet. If you need to create a larger vector with equally spaced values you will find a lot of small routines here in the forum posts which will do that for you.

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