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From: Oliver Fochler on 8 Feb 2010 07:57
Hi there,

in order to get my NIntegrate running properly it seems that I need to
ensure that my functions actually take numeric arguments (without
NIntegrate trying to do some symbolic stuff before).

For a simple case something like

f[x_?NumericQ] := (stuff)

seems to work fine. However, I do use vectors (lists) as function
arguments, i.e. f[x_, y_]:= (stuff) needs to be called as f[ {1,2,3},
4].
How do I test this for numerical values? I know that I can use
VectorQ[ x, NumericQ ] to check whether x is a vector that contains
only numeric values.

But how do I combine this into a pattern test, that can be used in an
argument list?
I would appreciate any help!

Cheers,
Oliver

From: DrMajorBob on 9 Feb 2010 02:45
For instance,

Clear[f]
f[list : {__?NumericQ}, y_?NumericQ] := {y, list}

f[{1, 2, 3}, 4]

{4, {1, 2, 3}}

Bobby

On Mon, 08 Feb 2010 06:54:52 -0600, Oliver Fochler
<janitor048(a)googlemail.com> wrote:

> Hi there,
>
> in order to get my NIntegrate running properly it seems that I need to
> ensure that my functions actually take numeric arguments (without
> NIntegrate trying to do some symbolic stuff before).
>
> For a simple case something like
>
> f[x_?NumericQ] := (stuff)
>
> seems to work fine. However, I do use vectors (lists) as function
> arguments, i.e. f[x_, y_]:= (stuff) needs to be called as f[ {1,2,3},
> 4].
> How do I test this for numerical values? I know that I can use
> VectorQ[ x, NumericQ ] to check whether x is a vector that contains
> only numeric values.
>
> But how do I combine this into a pattern test, that can be used in an
> argument list?
> I would appreciate any help!
>
> Cheers,
> Oliver
>


--
DrMajorBob(a)yahoo.com

From: Szabolcs Horvát on 9 Feb 2010 02:46
On 2010.02.08. 13:57, Oliver Fochler wrote:
> Hi there,
>
> in order to get my NIntegrate running properly it seems that I need to
> ensure that my functions actually take numeric arguments (without
> NIntegrate trying to do some symbolic stuff before).
>
> For a simple case something like
>
> f[x_?NumericQ] := (stuff)
>
> seems to work fine. However, I do use vectors (lists) as function
> arguments, i.e. f[x_, y_]:= (stuff) needs to be called as f[ {1,2,3},
> 4].
> How do I test this for numerical values? I know that I can use
> VectorQ[ x, NumericQ ] to check whether x is a vector that contains
> only numeric values.
>
> But how do I combine this into a pattern test, that can be used in an
> argument list?
> I would appreciate any help!

You can use for example f[ x_ ? (VectorQ[#, NumericQ]&) ] := ...

From: Patrick Scheibe on 9 Feb 2010 02:47
Hi,

what about

f[vec : {__?NumericQ}] := vec;

or

g[vec_?(VectorQ[#, NumericQ] &)] := vec


?

Cheers
Patrick

On Mon, 2010-02-08 at 07:54 -0500, Oliver Fochler wrote:
> Hi there,
>
> in order to get my NIntegrate running properly it seems that I need to
> ensure that my functions actually take numeric arguments (without
> NIntegrate trying to do some symbolic stuff before).
>
> For a simple case something like
>
> f[x_?NumericQ] := (stuff)
>
> seems to work fine. However, I do use vectors (lists) as function
> arguments, i.e. f[x_, y_]:= (stuff) needs to be called as f[ {1,2,3},
> 4].
> How do I test this for numerical values? I know that I can use
> VectorQ[ x, NumericQ ] to check whether x is a vector that contains
> only numeric values.
>
> But how do I combine this into a pattern test, that can be used in an
> argument list?
> I would appreciate any help!
>
> Cheers,
> Oliver
>


From: Bill Rowe on 9 Feb 2010 02:47
On 2/8/10 at 7:54 AM, janitor048(a)googlemail.com (Oliver Fochler)
wrote:

>in order to get my NIntegrate running properly it seems that I need
>to ensure that my functions actually take numeric arguments (without
>NIntegrate trying to do some symbolic stuff before).

>For a simple case something like

>f[x_?NumericQ] := (stuff)

>seems to work fine. However, I do use vectors (lists) as function
>arguments, i.e. f[x_, y_]:= (stuff) needs to be called as f[
>{1,2,3}, 4]. How do I test this for numerical values? I know that I
>can use VectorQ[ x, NumericQ ] to check whether x is a vector that
>contains only numeric values.

>But how do I combine this into a pattern test, that can be used in
>an argument list? I would appreciate any help!

You could use a conditional test instead of a pattern test. For example,

In[7]:= f[x_?VectorQ] := Total[x] /; And @@ (NumericQ /@ x)

In[8]:= f[RandomReal[1, 10]]

Out[8]= 4.46125

In[9]:= f[{a, b, c}]

Out[9]= f({a,b,c})

or if you prefer,

In[11]:= g[x_?(VectorQ[#, NumericQ] &)] := Total[x]

In[12]:= g[RandomReal[1, 10]]

Out[12]= 3.52661

In[13]:= g[{a, b, c}]

Out[13]= g({a,b,c})

Note, I've not tested these with large data sets. So, there may
be significant execution speed differences between these two options.


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