[Numpy-discussion] solving linear equations

Hanno Klemm klemm@phys.ethz...
Fri Mar 9 03:35:18 CST 2012


Hi,

have a look at scipy optimize. For a solution with only positive values you could consider using scipy.optimize.nnls, if you want more general (linear) constraints, have a look at the linear programming functions. 

Another possibility would be looking at openOpt, which has probably more general solvers.




On Mar 9, 2012, at 7:33, salahudeen razac wrote:

> 
> I wrote a script to solve the equation ‘P =Kd .V2 + Kl.VA.BT + C’ . To solve the equation I have used the matrix method.
> 
>  
> Ie, K*X = P          where
> 
> [P] = [             P1
> 
>                                 P2                                           a column matrix with the total powers P1, P2,P3…….PN at (V1,T1),(V2,T2)……(VN.TN) respectively,\
> 
>                         P3
> 
>                                 ..
> 
>                                 PN  ]
> 
>  
> 
>                                     [K] = [            V12      V1A.BT1    1
> 
>                                                             V22      V2A.BT2    1
> 
>                                                             V32      V3A.BT3    1
> 
>                                                             ………………………..
> 
>                                                             VN2      VNA.BTN    1 ]
> 
>  
> 
>                                     [X]= [ Kd                           A column matrix with the unknowns
> 
>                                                                 Kl
> 
>                                                                 C  ]
> 
>  
> Now in order to solve multiply both sides with KT, ie             KT.K.X = KTP or A.X = B where A= KT.K and B= KTP
> 
> 
> 
> Now we will get the matrix X by using linalg.solve(A,B) function which will eventually solve for a set of linear equations of the form Ax=B
> 
> 
> 
> I was able to get the solution. But it is not acceptable since some of the values are negative. SO I want to know is there any way to give some constraints like the solution should contain only positive values and give any range for the solution?
> 
> 
> 
> I also tried with linalg.lstsq and I am getting the same results
> 
> -----
> Salahudeen razak | +917760902602 
> 
> o__
>  _> /__
> (_) \(_)... Burn fat not fuel
> 
> 
> 
> 
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