Checking what a function depends on

Clash Royale CLAN TAG#URR8PPP

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I'd like to define specific partial derivative operators that change based on if the passed expression is a function of, for example, x vs. xi. I'm not finding anything in the documentation on how to code a check for the expressions dependence. My question is, if given some function f[x,y], how can I check the variables that it depends on?

calculus-and-analysis functions conditional

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edited Sep 5 at 21:31

kglr

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asked Sep 5 at 21:12

mads

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  Possible duplicate of How to define custom differential operator using the arguments of the expression?
  – Carl Woll
  Sep 5 at 21:43
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  I think it should be possible to also use DownValues[f] to find what the function depends on, since the DownValues has the function signature right there. It just needs to be parsed out and to extract all the symbols from inside f[x_,y_,....] and this part might be tricky to do. ?DownValues
  – Nasser
  Sep 6 at 1:50
  
  

  
  
  
  

add a comment | 

up vote
7
down vote

favorite

1

I'd like to define specific partial derivative operators that change based on if the passed expression is a function of, for example, x vs. xi. I'm not finding anything in the documentation on how to code a check for the expressions dependence. My question is, if given some function f[x,y], how can I check the variables that it depends on?

calculus-and-analysis functions conditional

share|improve this question

edited Sep 5 at 21:31

kglr

159k8183383

asked Sep 5 at 21:12

mads

383

New contributor

mads is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.

• 
  
  
  

  
  3
  

  
  
  
  
  
  

  
  Possible duplicate of How to define custom differential operator using the arguments of the expression?
  – Carl Woll
  Sep 5 at 21:43
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  I think it should be possible to also use DownValues[f] to find what the function depends on, since the DownValues has the function signature right there. It just needs to be parsed out and to extract all the symbols from inside f[x_,y_,....] and this part might be tricky to do. ?DownValues
  – Nasser
  Sep 6 at 1:50
  
  

  
  
  
  

add a comment | 

up vote
7
down vote

favorite

1

up vote
7
down vote

favorite

1

1

I'd like to define specific partial derivative operators that change based on if the passed expression is a function of, for example, x vs. xi. I'm not finding anything in the documentation on how to code a check for the expressions dependence. My question is, if given some function f[x,y], how can I check the variables that it depends on?

calculus-and-analysis functions conditional

share|improve this question

edited Sep 5 at 21:31

kglr

159k8183383

asked Sep 5 at 21:12

mads

383

New contributor

mads is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.

I'd like to define specific partial derivative operators that change based on if the passed expression is a function of, for example, x vs. xi. I'm not finding anything in the documentation on how to code a check for the expressions dependence. My question is, if given some function f[x,y], how can I check the variables that it depends on?

calculus-and-analysis functions conditional

share|improve this question

edited Sep 5 at 21:31

kglr

159k8183383

asked Sep 5 at 21:12

mads

383

New contributor

mads is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.

share|improve this question

share|improve this question

edited Sep 5 at 21:31

kglr

159k8183383

edited Sep 5 at 21:31

kglr

159k8183383

edited Sep 5 at 21:31

kglr

159k8183383

159k8183383

asked Sep 5 at 21:12

mads

383

New contributor

mads is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.

asked Sep 5 at 21:12

mads

383

asked Sep 5 at 21:12

mads

383

383

New contributor

mads is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.

New contributor

mads is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.

mads is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.

• 
  
  
  

  
  3
  

  
  
  
  
  
  

  
  Possible duplicate of How to define custom differential operator using the arguments of the expression?
  – Carl Woll
  Sep 5 at 21:43
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  I think it should be possible to also use DownValues[f] to find what the function depends on, since the DownValues has the function signature right there. It just needs to be parsed out and to extract all the symbols from inside f[x_,y_,....] and this part might be tricky to do. ?DownValues
  – Nasser
  Sep 6 at 1:50
  
  

  
  
  
  

add a comment | 

• 
  
  
  

  
  3
  

  
  
  
  
  
  

  
  Possible duplicate of How to define custom differential operator using the arguments of the expression?
  – Carl Woll
  Sep 5 at 21:43
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  I think it should be possible to also use DownValues[f] to find what the function depends on, since the DownValues has the function signature right there. It just needs to be parsed out and to extract all the symbols from inside f[x_,y_,....] and this part might be tricky to do. ?DownValues
  – Nasser
  Sep 6 at 1:50
  
  

  
  
  
  

3

3

Possible duplicate of How to define custom differential operator using the arguments of the expression?
– Carl Woll
Sep 5 at 21:43

Possible duplicate of How to define custom differential operator using the arguments of the expression?
– Carl Woll
Sep 5 at 21:43

I think it should be possible to also use DownValues[f] to find what the function depends on, since the DownValues has the function signature right there. It just needs to be parsed out and to extract all the symbols from inside f[x_,y_,....] and this part might be tricky to do. ?DownValues
– Nasser
Sep 6 at 1:50

I think it should be possible to also use DownValues[f] to find what the function depends on, since the DownValues has the function signature right there. It just needs to be parsed out and to extract all the symbols from inside f[x_,y_,....] and this part might be tricky to do. ?DownValues
– Nasser
Sep 6 at 1:50

add a comment | 

1 Answer
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12
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accepted

Perhaps Internal`DependsOnQ:

h = f[x, g[y]];
Internal`DependsOnQ[h, #] & /@ x, y, g[y], w

True, True, True, False

share|improve this answer

answered Sep 5 at 21:30

kglr

159k8183383

add a comment | 

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1 Answer
1

active

oldest

votes

1 Answer
1

active

oldest

votes

active

oldest

votes

active

oldest

votes

up vote
12
down vote



accepted

Perhaps Internal`DependsOnQ:

h = f[x, g[y]];
Internal`DependsOnQ[h, #] & /@ x, y, g[y], w

True, True, True, False

share|improve this answer

answered Sep 5 at 21:30

kglr

159k8183383

add a comment | 

up vote
12
down vote



accepted

Perhaps Internal`DependsOnQ:

h = f[x, g[y]];
Internal`DependsOnQ[h, #] & /@ x, y, g[y], w

True, True, True, False

share|improve this answer

answered Sep 5 at 21:30

kglr

159k8183383

add a comment | 

up vote
12
down vote



accepted

up vote
12
down vote



accepted

Perhaps Internal`DependsOnQ:

h = f[x, g[y]];
Internal`DependsOnQ[h, #] & /@ x, y, g[y], w

True, True, True, False

share|improve this answer

answered Sep 5 at 21:30

kglr

159k8183383

Perhaps Internal`DependsOnQ:

h = f[x, g[y]];
Internal`DependsOnQ[h, #] & /@ x, y, g[y], w

True, True, True, False

share|improve this answer

answered Sep 5 at 21:30

kglr

159k8183383

share|improve this answer

share|improve this answer

answered Sep 5 at 21:30

kglr

159k8183383

answered Sep 5 at 21:30

kglr

159k8183383

answered Sep 5 at 21:30

kglr

159k8183383

159k8183383

add a comment | 

add a comment | 

mads is a new contributor. Be nice, and check out our Code of Conduct.

 

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