On Jul 30, 1:55 pm, mbwel...@gmail.com wrote:
> On Jul 30, 3:57 am, Jeremy Bailin <astroco...@gmail.com> wrote:
>
>
>
>> On Jul 30, 4:33 am, Wox <nom...@hotmail.com> wrote:
>
>>> On Tue, 29 Jul 2008 23:19:19 -0700 (PDT), mbwel...@gmail.com wrote:
>>>> On Jul 29, 7:27 pm, Chris <beaum...@ifa.hawaii.edu> wrote:
>>>> > On Jul 29, 1:12 pm, mbwel...@gmail.com wrote:
>
>>>> > > Hello,
>
>>>> > > I have need of some experienced users with sort of a newbie question.
>
>>>> > > I am writing a code that needs a summation in it, this is what I have
>>>> > > thus far:
>
>>>> > > v= ; volume of region
>>>> > > a= ; area of region
>>>> > > o= 60*!pi/180 ; fault dip angle
>>>> > > g= ; scaling factor
>>>> > > t= 150 ; elastic lithosphere thickness
>>>> > > h= ; depth of faulting
>
>>>> > > ind_small = where(thaext[1,*] lt t)
>>>> > > ind_large = where(thaext[1,*] ge t)
>>>> > > thaext_small = thaext[*,ind_small]
>>>> > > thaext_large = thaext[*,ind_large]
>
>>>> > > ens=(sin(o)*cos(o)/v)* ; horizonatal normal strain for small faults
>>>> > > enl=(cos(o)/a)* ; horizonatal normal strain for
>>>> > > large faults
>>>> > > evs=(-sin(o)*cos(o)/v)* ; vertical normal strain for small faults
>>>> > > evl=(-cos(o)/a)* ; vertical normal strain for large faults
>
>>>> > > The summation needs to be after * in the ens, enl, evs and evl
>>>> > > fields.
>>>> > > It must be of the form:
>>>> > > summation N, i=0 [Di Li Hi] for small faults, where N = ind_small, Hi=
>>>> > > T/sin(o) and
>>>> > > summation N, i=0 [Di Li] for large faults, where N=ind_large
>
>>>> > > Could anyone provide any insight/guidance?
>
>>>> > > Thanks,
>>>> > > ~Matt
>
>>>> > I don't know what some of your variables are (Li? Di?), but you might
>>>> > want to look at TOTAL() to start- you can use that to do most
>>>> > summation tasks.
>
>>>> L and D are data from a ascii table that is already ready in, while i
>>>> is the indice of the summation. I've looked at total, but the examples
>>>> were sorely lacking. I was hoping that perhaps a useful example, given
>>>> my code and desire, could be supplied.
>
>>>> ~Matt
>
>>> I'm not sure what you mean with "summation N, i=0 [Di Li Hi] ... where
>>> N=ind_small". The index i goes from 0 to what? And what are you
>>> summing? D[i]*L[i]*H[i]?
>
>> Okay, if I understand it correctly, then what you're saying is that in
>> ind_small you multiply by an extra factor of t/sin(o) inside the sum,
>> but not in ind_large?
>
>> H = replicate(1., n_elements(D))
>> H[ind_small] = t/sin(o)
>> summation = total(D*L*H)
>
>> Is that what you're looking for?
>
>> (by the way, look up !RADEG).
>
>> -Jeremy.
>
> Thanks for the responses.
> I think that I did not adequately explain what I needed to do, Let me
> be more specific now. (this might be a little complicated)
>
> I have a .sav file which is a FLOAT array[2,7923] but may go as high
> as [2,18000] and the forms are as such: [id, Length].
>
> ind_small and ind_large are where I select the lengths to be smaller
> or larger, respectively, than t. Then place them back into the new
> matrices thaext_small and thaext_large. (not completely sure if this
> is necessary.)
>
> Now comes the part that I am a little confused on how to program.
>
> ens, enl, evs and evl fields are going to be a constant * a summation
> (which will be different for all four).
>
> The number of sums or (N) needs to be equal to the number of the
> faults down selected by Ind_small (or since ind_small =
> where(thaext[1,*] lt t), it needs to sum the number of the second
> column in the array). This number will be different for bot the large
> and small cases (eg. ind_large = where(thaext[1,*] ge t)). So, i then
> should be # of points in column 2 of ind_small/ind_large - 1 (I would
> think).
>
> The summation is [D[i]*L[i]*H[i]] for small faults and the summation
> is [D[i]*L[i]] for large faults, where:
> D[i]=C[i]*L[i] for small faults and
> D[i]=C[i]*H[i] for large faults,
> L[i]= length (from column 2 of thaext_small/thaext_large) and
> H[i]=(1/2 or 1/3)*L[i] for small faults and
> H[i] = t/sin(o) for large faults and
> C[i] may or may not be a constant
>
> This should now read as constant * summation[C[i]*L[i]*L[i]*L[i]] for
> small faults and constant * summation [C[i]*L[i]] for large
> faults.
>
> I think that's everything I need to be able to do, hopefully it's a
> bit clearer now.
>
> Thanks,
> ~Matt
Its still a bit confusing to me, but let me guess at what you're
trying to do (sorry if I'm still off)
You have some vector of ID's and lengths. You want to select out
certain rows of this array based on the value of lengths. You then
want to use these row numbers as reference to other arrays (like C and
L, which i assume are the same length as the ID/Length array). You
want to multiply the selected tables together and sum up the rows
which pass this criteria (some test on the length, like gt t). Is that
close? If so, do something like this
id ; [id, length] vector
a ; random vector 1
b ; random vector 2
want to sum the product of a and b for the rows for which the
corresponding id length is greater than, say 5
test=where(id[1,*] gt 5, count)
if count ge 0 then result=total(a[test]*b[test]) else print, 'No good
rows!'
return, result
am i getting close yet?
chris
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