[Scilab-users] Summation query in Scilab

[Lester Anderson]

Hi Serge

A quick question. In the context of the equation, what is the purpose of
the ones(t) part? The help states that this creates a matrix composed of
ones.

g=c*sum((B./(m1.^3*%pi).*sin(m1*%pi/B))*ones(t).*exp(-(m1.^2*t/tau)),1);

Probabaly a very simple answer.

Cheers

Lester

On 12 December 2012 22:46, Lester Anderson <arctica1963 at gmail.com> wrote:

> Many thanks Serge :) That worked great!
> Helps to see how the syntax should work.
>
> Cheers
>
> Lester
>
>
> On 12 December 2012 22:29, Serge Steer <serge.steer at inria.fr> wrote:
>
>> I think the following code fullfil your wish...
>>
>>
>> n = 0:1:20 ;// series in the expansionB = 1.5; //beta factorTm = 1300*274.15; //base-lithosphere temperature [C]tau = 62.8; //lithosphere cooling thermal decay constant [Ma]a = 125000; //equilibrium lithospheric thickness [m]alpha = 3.28e-5 ;//thermal expansion coefficient K^-1// Tm needs to be converted to Kelvin - multiply by 274.15rho = 3300;t = 0:5:150; //lithosphere age [Ma]G = 6.67e-11;
>> // LTGA with increasing age of oceanic lithosphere
>> c=8*G*alpha*rho*a*Tm/%pi;m=(0:20)';m1=2*m+1;g=c*sum((B./(m1.^3*%pi).*sin(m1*%pi/B))*ones(t).*exp(-(m1.^2*t/tau)),1);clf;plot(t,g)
>>
>>
>> Serge Steer
>> ------------------------------
>>
>> *De: *"Lester Anderson" <arctica1963 at gmail.com>
>> *À: *"International users mailing list for Scilab." <
>> users at lists.scilab.org>
>> *Envoyé: *Mardi 11 Décembre 2012 08:16:01
>> *Objet: *[Scilab-users] Summation query in Scilab
>>
>>
>> Hello,
>>
>> I have an equation structured like in the attached, however I am unsure
>> of the correct syntax to compute in Scilab.
>>
>> One can calculate the first term of the expansion but obvioulsy it needs
>> to go to a large number (approximating infinity eg 20).
>> I am sure this is something very straightforward!
>>
>> Any ideas welcome.
>>
>> Thanks for the help
>>
>> Lester
>>
>> att: image of equation, test code
>>
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