How do I make LinearModelFit flexible to number of parameters using FromLetterNumber?

Clash Royale CLAN TAG#URR8PPP

up vote
4
down vote

favorite

I want to run LinearModelFit where the number of parameters is not fixed. For example, the following

i = 2;
data = RandomReal[20,10,3+i];
lm1 = LinearModelFit[data,FromLetterNumber[Range[2+i]],FromLetterNumber[Range[2+i]];

doesn't work, whereas

lm1 = LinearModelFit[data,a,b,c,d,a,b,c,d]

works as per described, despite FromLetterNumber[Range[2+i]] == a,b,c,d

Can this be made to work using some kind of Hold or do I need to resort to a design matrix, response vector format?

fitting hold

share|improve this question

asked Aug 6 at 7:54

Thadeu Freitas Filho

866

add a comment | 

up vote
4
down vote

favorite

I want to run LinearModelFit where the number of parameters is not fixed. For example, the following

i = 2;
data = RandomReal[20,10,3+i];
lm1 = LinearModelFit[data,FromLetterNumber[Range[2+i]],FromLetterNumber[Range[2+i]];

doesn't work, whereas

lm1 = LinearModelFit[data,a,b,c,d,a,b,c,d]

works as per described, despite FromLetterNumber[Range[2+i]] == a,b,c,d

Can this be made to work using some kind of Hold or do I need to resort to a design matrix, response vector format?

fitting hold

share|improve this question

asked Aug 6 at 7:54

Thadeu Freitas Filho

866

add a comment | 

up vote
4
down vote

favorite

up vote
4
down vote

favorite

I want to run LinearModelFit where the number of parameters is not fixed. For example, the following

i = 2;
data = RandomReal[20,10,3+i];
lm1 = LinearModelFit[data,FromLetterNumber[Range[2+i]],FromLetterNumber[Range[2+i]];

doesn't work, whereas

lm1 = LinearModelFit[data,a,b,c,d,a,b,c,d]

works as per described, despite FromLetterNumber[Range[2+i]] == a,b,c,d

Can this be made to work using some kind of Hold or do I need to resort to a design matrix, response vector format?

fitting hold

share|improve this question

asked Aug 6 at 7:54

Thadeu Freitas Filho

866

I want to run LinearModelFit where the number of parameters is not fixed. For example, the following

i = 2;
data = RandomReal[20,10,3+i];
lm1 = LinearModelFit[data,FromLetterNumber[Range[2+i]],FromLetterNumber[Range[2+i]];

doesn't work, whereas

lm1 = LinearModelFit[data,a,b,c,d,a,b,c,d]

works as per described, despite FromLetterNumber[Range[2+i]] == a,b,c,d

Can this be made to work using some kind of Hold or do I need to resort to a design matrix, response vector format?

fitting hold

share|improve this question

asked Aug 6 at 7:54

Thadeu Freitas Filho

866

share|improve this question

share|improve this question

asked Aug 6 at 7:54

Thadeu Freitas Filho

866

asked Aug 6 at 7:54

Thadeu Freitas Filho

866

asked Aug 6 at 7:54

Thadeu Freitas Filho

866

866

add a comment | 

add a comment | 

1 Answer
1

active

oldest

votes

up vote
5
down vote



accepted

FromLetterNumber returns a String:

Head @ FromLetterNumber @ 3

String

You can wrap the strings returned by FromLetterNumber with Symbol or ToExpression to get Symbols:

lm1 = LinearModelFit[data, Symbol /@ FromLetterNumber[Range[2+i]], 
 Symbol /@ FromLetterNumber[Range[2+i]]];
Normal @ lm1

9.60642 + 0.175108 a - 0.723711 b + 0.850788 c - 0.198777 d

Alternatively,

lm2 = LinearModelFit[data, Array[a, 2 + i], Array[a, 2 + i] ] ;
Normal @ lm2

9.60642 + 0.175108 a[1] - 0.723711 a[2] + 0.850788 a[3] - 0.198777 a[4]

share|improve this answer

edited Aug 7 at 0:00

answered Aug 6 at 8:06

kglr

154k8179374

• 
  
  
  

  
  2
  

  
  
  
  
  
  

  
  The Array version should be the canonical choice, IMHO. +1
  – Marius Ladegård Meyer
  Aug 6 at 9:34
  

  
  
  
  

add a comment | 

Your Answer

StackExchange.ifUsing("editor", function ()
return StackExchange.using("mathjaxEditing", function ()
StackExchange.MarkdownEditor.creationCallbacks.add(function (editor, postfix)
StackExchange.mathjaxEditing.prepareWmdForMathJax(editor, postfix, [["$", "$"], ["\\(","\\)"]]);
);
);
, "mathjax-editing");

StackExchange.ready(function()
var channelOptions =
tags: "".split(" "),
id: "387"
;
initTagRenderer("".split(" "), "".split(" "), channelOptions);

StackExchange.using("externalEditor", function()
// Have to fire editor after snippets, if snippets enabled
if (StackExchange.settings.snippets.snippetsEnabled)
StackExchange.using("snippets", function()
createEditor();
);

else
createEditor();

);

function createEditor()
StackExchange.prepareEditor(
heartbeatType: 'answer',
convertImagesToLinks: false,
noModals: false,
showLowRepImageUploadWarning: true,
reputationToPostImages: null,
bindNavPrevention: true,
postfix: "",
onDemand: true,
discardSelector: ".discard-answer"
,immediatelyShowMarkdownHelp:true
);



);

 

draft saved

draft discarded

Sign up or log in

StackExchange.ready(function ()
StackExchange.helpers.onClickDraftSave('#login-link');
);

Sign up using Google

Sign up using Facebook

Sign up using Email and Password

Post as a guest

Name Email

StackExchange.ready(
function ()
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fmathematica.stackexchange.com%2fquestions%2f179557%2fhow-do-i-make-linearmodelfit-flexible-to-number-of-parameters-using-fromletternu%23new-answer', 'question_page');

);

Post as a guest

Name Email

1 Answer
1

active

oldest

votes

1 Answer
1

active

oldest

votes

active

oldest

votes

active

oldest

votes

up vote
5
down vote



accepted

FromLetterNumber returns a String:

Head @ FromLetterNumber @ 3

String

You can wrap the strings returned by FromLetterNumber with Symbol or ToExpression to get Symbols:

lm1 = LinearModelFit[data, Symbol /@ FromLetterNumber[Range[2+i]], 
 Symbol /@ FromLetterNumber[Range[2+i]]];
Normal @ lm1

9.60642 + 0.175108 a - 0.723711 b + 0.850788 c - 0.198777 d

Alternatively,

lm2 = LinearModelFit[data, Array[a, 2 + i], Array[a, 2 + i] ] ;
Normal @ lm2

9.60642 + 0.175108 a[1] - 0.723711 a[2] + 0.850788 a[3] - 0.198777 a[4]

share|improve this answer

edited Aug 7 at 0:00

answered Aug 6 at 8:06

kglr

154k8179374

• 
  
  
  

  
  2
  

  
  
  
  
  
  

  
  The Array version should be the canonical choice, IMHO. +1
  – Marius Ladegård Meyer
  Aug 6 at 9:34
  

  
  
  
  

add a comment | 

up vote
5
down vote



accepted

FromLetterNumber returns a String:

Head @ FromLetterNumber @ 3

String

You can wrap the strings returned by FromLetterNumber with Symbol or ToExpression to get Symbols:

lm1 = LinearModelFit[data, Symbol /@ FromLetterNumber[Range[2+i]], 
 Symbol /@ FromLetterNumber[Range[2+i]]];
Normal @ lm1

9.60642 + 0.175108 a - 0.723711 b + 0.850788 c - 0.198777 d

Alternatively,

lm2 = LinearModelFit[data, Array[a, 2 + i], Array[a, 2 + i] ] ;
Normal @ lm2

9.60642 + 0.175108 a[1] - 0.723711 a[2] + 0.850788 a[3] - 0.198777 a[4]

share|improve this answer

edited Aug 7 at 0:00

answered Aug 6 at 8:06

kglr

154k8179374

• 
  
  
  

  
  2
  

  
  
  
  
  
  

  
  The Array version should be the canonical choice, IMHO. +1
  – Marius Ladegård Meyer
  Aug 6 at 9:34
  

  
  
  
  

add a comment | 

up vote
5
down vote



accepted

up vote
5
down vote



accepted

FromLetterNumber returns a String:

Head @ FromLetterNumber @ 3

String

You can wrap the strings returned by FromLetterNumber with Symbol or ToExpression to get Symbols:

lm1 = LinearModelFit[data, Symbol /@ FromLetterNumber[Range[2+i]], 
 Symbol /@ FromLetterNumber[Range[2+i]]];
Normal @ lm1

9.60642 + 0.175108 a - 0.723711 b + 0.850788 c - 0.198777 d

Alternatively,

lm2 = LinearModelFit[data, Array[a, 2 + i], Array[a, 2 + i] ] ;
Normal @ lm2

9.60642 + 0.175108 a[1] - 0.723711 a[2] + 0.850788 a[3] - 0.198777 a[4]

share|improve this answer

edited Aug 7 at 0:00

answered Aug 6 at 8:06

kglr

154k8179374

FromLetterNumber returns a String:

Head @ FromLetterNumber @ 3

String

You can wrap the strings returned by FromLetterNumber with Symbol or ToExpression to get Symbols:

lm1 = LinearModelFit[data, Symbol /@ FromLetterNumber[Range[2+i]], 
 Symbol /@ FromLetterNumber[Range[2+i]]];
Normal @ lm1

9.60642 + 0.175108 a - 0.723711 b + 0.850788 c - 0.198777 d

Alternatively,

lm2 = LinearModelFit[data, Array[a, 2 + i], Array[a, 2 + i] ] ;
Normal @ lm2

9.60642 + 0.175108 a[1] - 0.723711 a[2] + 0.850788 a[3] - 0.198777 a[4]

share|improve this answer

edited Aug 7 at 0:00

answered Aug 6 at 8:06

kglr

154k8179374

share|improve this answer

share|improve this answer

edited Aug 7 at 0:00

edited Aug 7 at 0:00

edited Aug 7 at 0:00

answered Aug 6 at 8:06

kglr

154k8179374

answered Aug 6 at 8:06

kglr

154k8179374

answered Aug 6 at 8:06

kglr

154k8179374

154k8179374

• 
  
  
  

  
  2
  

  
  
  
  
  
  

  
  The Array version should be the canonical choice, IMHO. +1
  – Marius Ladegård Meyer
  Aug 6 at 9:34
  

  
  
  
  

add a comment | 

• 
  
  
  

  
  2
  

  
  
  
  
  
  

  
  The Array version should be the canonical choice, IMHO. +1
  – Marius Ladegård Meyer
  Aug 6 at 9:34
  

  
  
  
  

2

2

The Array version should be the canonical choice, IMHO. +1
– Marius Ladegård Meyer
Aug 6 at 9:34

The Array version should be the canonical choice, IMHO. +1
– Marius Ladegård Meyer
Aug 6 at 9:34

add a comment | 

 

draft saved

draft discarded

 

draft saved

draft discarded

Sign up or log in

StackExchange.ready(function ()
StackExchange.helpers.onClickDraftSave('#login-link');
);

Sign up using Google

Sign up using Facebook

Sign up using Email and Password

Post as a guest

Name Email

StackExchange.ready(
function ()
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fmathematica.stackexchange.com%2fquestions%2f179557%2fhow-do-i-make-linearmodelfit-flexible-to-number-of-parameters-using-fromletternu%23new-answer', 'question_page');

);

Post as a guest

Name Email

Sign up or log in

StackExchange.ready(function ()
StackExchange.helpers.onClickDraftSave('#login-link');
);

Sign up using Google

Sign up using Facebook

Sign up using Email and Password

Post as a guest

Name Email

Sign up or log in

StackExchange.ready(function ()
StackExchange.helpers.onClickDraftSave('#login-link');
);

Sign up using Google

Sign up using Facebook

Sign up using Email and Password

Post as a guest

Name Email

Sign up or log in

StackExchange.ready(function ()
StackExchange.helpers.onClickDraftSave('#login-link');
);

Sign up using Google

Sign up using Facebook

Sign up using Email and Password

Sign up using Google

Sign up using Facebook

Sign up using Email and Password

Post as a guest

Name Email

Name Email

Name

Email

Name Email

Name

Email