Polyfit with three variable

[SGM]

Hi,

I need help with linear regression with three variables.

I was running the following code:

   N_Liner=1; 
    P_Liner=polyfit(G,Temp,I_PV,N_Liner)

getting the following error "error: polyfit: N must be a non-negative integer".

Is there any way out?

Regards,

Swagata

[Doug Stewart-4]

On Sun, Dec 20, 2020 at 7:13 AM swagata Mukherjee <[hidden email]> wrote:

Hi,

I need help with linear regression with three variables.

I was running the following code:

   N_Liner=1; 
    P_Liner=polyfit(G,Temp,I_PV,N_Liner)

getting the following error "error: polyfit: N must be a non-negative integer".

Is there any way out?

Regards,

Swagata

Show us what these values are.

G

Temp

I_PV

N_Liner

--

[SGM]

Hi,

The files are attached.

Regards,

Swagata

On Sun, Dec 20, 2020 at 5:57 PM Doug Stewart <[hidden email]> wrote:

On Sun, Dec 20, 2020 at 7:13 AM swagata Mukherjee <[hidden email]> wrote:

Hi,

I need help with linear regression with three variables.

I was running the following code:

   N_Liner=1; 
    P_Liner=polyfit(G,Temp,I_PV,N_Liner)

getting the following error "error: polyfit: N must be a non-negative integer".

Is there any way out?

Regards,

Swagata

Show us what these values are.

G

Temp

I_PV

N_Liner

--

DAS

[Doug Stewart-4]

On Sun, Dec 20, 2020 at 8:16 AM swagata Mukherjee <[hidden email]> wrote:

Hi,

The files are attached.

Regards,

Swagata

On Sun, Dec 20, 2020 at 5:57 PM Doug Stewart <[hidden email]> wrote:

On Sun, Dec 20, 2020 at 7:13 AM swagata Mukherjee <[hidden email]> wrote:

Hi,

I need help with linear regression with three variables.

I was running the following code:

   N_Liner=1; 
    P_Liner=polyfit(G,Temp,I_PV,N_Liner)

getting the following error "error: polyfit: N must be a non-negative integer".

Is there any way out?

Regards,

Swagata

Show us what these values are.

G

Temp

I_PV

N_Liner

--

DAS

If you look at the help for polyfit:

help polyfit

You will see that your inputs to polyfit are wrong. 

 you should give it the x and y values and the deg. of polynomial that you want.

--

[SGM]

Hi,

My question is whether we have any method by which I can use regression with 3 variables like polyfit(x,y,z,N)?

Regards

On Sun 20 Dec, 2020, 8:24 PM Doug Stewart, <[hidden email]> wrote:

On Sun, Dec 20, 2020 at 8:16 AM swagata Mukherjee <[hidden email]> wrote:

Hi,

The files are attached.

Regards,

Swagata

On Sun, Dec 20, 2020 at 5:57 PM Doug Stewart <[hidden email]> wrote:

On Sun, Dec 20, 2020 at 7:13 AM swagata Mukherjee <[hidden email]> wrote:

Hi,

I need help with linear regression with three variables.

I was running the following code:

   N_Liner=1; 
    P_Liner=polyfit(G,Temp,I_PV,N_Liner)

getting the following error "error: polyfit: N must be a non-negative integer".

Is there any way out?

Regards,

Swagata

Show us what these values are.

G

Temp

I_PV

N_Liner

--

DAS

If you look at the help for polyfit:

help polyfit

You will see that your inputs to polyfit are wrong. 

 you should give it the x and y values and the deg. of polynomial that you want.

--

DAS

[mmuetzel]

Am 20. Dezember 2020 um 15:57 Uhr schrieb "swagata Mukherjee":
> Hi,
> My question is whether we have any method by which I can use regression with 3 variables like polyfit(x,y,z,N)?
> Regards 

This answer on the discourse forum might be helpful:
https://octave.discourse.group/t/execucao-do-codigo/497/8

In principle, that approach also works for multi-dimensional polynomials of higher degree.

HTH,
Markus

[Andreas Stahel]

mmuetzel wrote

> Am 20. Dezember 2020 um 15:57 Uhr schrieb "swagata Mukherjee":
>> Hi,
>> My question is whether we have any method by which I can use regression
>> with 3 variables like polyfit(x,y,z,N)?
>> Regards 
>
> This answer on the discourse forum might be helpful:
> https://octave.discourse.group/t/execucao-do-codigo/497/8
>
> In principle, that approach also works for multi-dimensional polynomials
> of higher degree.
>
> HTH,
> Markus

The linl given by Markus is a good one.

You might have a look at the command LinearRegression() in the optimization
package or the command regress().
To deal with multiple variable have a look at Section 2.2 in
https://web.sha1.bfh.science/Labs/PWF/Documentation/OctaveAtBFH.pdf
Example 2 (p. 162) and Example 4 (p. 168) use multiple variables.

I hope this helps

Andreas




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