| Re: Newbie question concerning summations/loops in IDL [message #61732] |
Wed, 30 July 2008 03:57  |
Jeremy Bailin
Messages: 618
Registered: April 2008
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Senior Member |
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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.
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| Re: Newbie question concerning summations/loops in IDL [message #61734 is a reply to message #61732] |
Wed, 30 July 2008 01:33  |
Wox
Messages: 184
Registered: August 2006
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Senior Member |
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On Tue, 29 Jul 2008 23:19:19 -0700 (PDT), mbweller@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]?
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| Re: Newbie question concerning summations/loops in IDL [message #61735 is a reply to message #61734] |
Tue, 29 July 2008 23:19 |
mbweller
Messages: 24
Registered: July 2008
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Junior Member |
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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
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| Re: Newbie question concerning summations/loops in IDL [message #61736 is a reply to message #61735] |
Tue, 29 July 2008 19:27 |
Chris[6]
Messages: 84
Registered: July 2008
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Member |
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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.
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| Re: Newbie question concerning summations/loops in IDL [message #61812 is a reply to message #61732] |
Wed, 30 July 2008 16:55 |
mbweller
Messages: 24
Registered: July 2008
|
Junior Member |
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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
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