Re: Apply Polyval to Array

[Thomas D. Dean]

On 06/12/2016 08:25 PM, Doug Stewart wrote:
> On Sun, Jun 12, 2016 at 10:03 PM, Thomas D. Dean <address@hidden
> <mailto:address@hidden>> wrote:
>
>     I want to vectorize this:
>
>     p1 = [1,2,3;4,5,6;7,8,9];
>     for idx=1:3
>        polyval(p1(idx,:),0)
>     endfor
>
>     cellfun("polyval",{p1},{[0;0;0]}); ## fails
>     arrayfun("polyval",p1,0 "UniformOutput",false)); ## wrong
>     arrayfun("polyval",p1,zeros(3,3), "UniformOutput",false); ## wrong
>
>     Tom Dean
>
>     _______________________________________________
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>     address@hidden <mailto:address@hidden>
>     https://lists.gnu.org/mailman/listinfo/help-octave
>
>
> does this help
>
> p1 = [1,2,3;4,5,6;7,8,9];
> t=[1 2 3]
> f=@(t) polyval(p1(t,:),0)
> arrayfun(f,t)
>
> --
My initial polynomials are (3,14)


octave:693> p1
p1 =
 Columns 1 through 6:
 2.3055e+06 2.3055e+06 2.3056e+06 2.3056e+06 2.3056e+06 2.3056e+06
 2.3059e+06 2.3060e+06 2.3060e+06 2.3060e+06 2.3061e+06 2.3061e+06
 2.3064e+06 2.3064e+06 2.3064e+06 2.3065e+06 2.3065e+06 2.3065e+06
 Columns 7 through 12:
 2.3057e+06 2.3057e+06 2.3057e+06 2.3058e+06 2.3058e+06 2.3058e+06
 2.3061e+06 2.3062e+06 2.3062e+06 2.3062e+06 2.3063e+06 2.3063e+06
 2.3066e+06 2.3066e+06 2.3066e+06 2.3067e+06 2.3067e+06 2.3067e+06
 Columns 13 and 14:
 2.3059e+06 2.3059e+06
 2.3063e+06 2.3064e+06
 2.3068e+06 2.3068e+06

These are the coefficients of the Chebyshev polynomials from the JPL 
DE405.  I need to evaluate them at several points.  And, I will be doing 
this in a loop.
v = an array of values, in the range 0..1
x=polyval(p1(1,:),v(1))
y=polyval(p1(2,:),v(1))
z=polyval(p1(3,:),v(1))

Tom Dean