Find the position of maximum value.

[Sunny123@ntlworld.com]

hello

i am trying to find the maximum value of a function and where it occur.

i.e there is an array

x |y
=============
|
|
|
|
|
|

and i want to find where the maximum occurs and at what value of x.

i tried fabs but it isnt quite right.

thanks

[mlimber]

Re: Find the position of maximum value.

Sunny123@ntlwor ld.com wrote:[color=blue]
> hello
>
> i am trying to find the maximum value of a function and where it occur.
>
> i.e there is an array
>
> x |y
> =============
> |
> |
> |
> |
> |
> |
>
> and i want to find where the maximum occurs and at what value of x.
>
> i tried fabs but it isnt quite right.[/color]

Show us the code, and we might be able to help. Be aware, though, that
this forum is for discussing the C++ language in particular, not
programming or applications in general. See this FAQ for what is
on-topic here:

http://www.parashift.com/c++-faq-lite/how-to-post.html#faq-5.9

Cheers! --M

[Victor Bazarov]

Re: Find the position of maximum value.

Sunny123@ntlwor ld.com wrote:[color=blue]
> i am trying to find the maximum value of a function and where it
> occur.
>
> i.e there is an array
>
> x |y
> =============
> |
> |
> |
> |
> |
> |
>
> and i want to find where the maximum occurs and at what value of x.
>
> i tried fabs but it isnt quite right.[/color]

I believe some of it is covered in the FAQ (you can find the FAQ
here: http://www.parashift.com/c++-faq-lite/)

Start in section 5.

V
--
Please remove capital 'A's when replying by e-mail
I do not respond to top-posted replies, please don't ask

[Jim Langston]

Re: Find the position of maximum value.

<Sunny123@ntlwo rld.com> wrote in message
news:1147370036 .197283.27950@j 33g2000cwa.goog legroups.com...[color=blue]
> hello
>
> i am trying to find the maximum value of a function and where it occur.
>
> i.e there is an array
>
> x |y
> =============
> |
> |
> |
> |
> |
> |
>
> and i want to find where the maximum occurs and at what value of x.
>
> i tried fabs but it isnt quite right.[/color]

Show us what you tried with fabs.

[osmium]

Re: Find the position of maximum value.

<Sunny123@ntlwo rld.com> wrote:
[color=blue]
> i am trying to find the maximum value of a function and where it occur.
>
> i.e there is an array
>
> x |y
> =============
> |
> |
> |
> |
> |
> |
>
> and i want to find where the maximum occurs and at what value of x.
>
> i tried fabs but it isnt quite right.[/color]

I doubt if fabs has any bearing on your problem. Try something like this.

double lsf = a[0]; // lsf - largest so far, a - array
int lsf_ix = 0;

Now go through the array, starting at index = 1, modifying lsf and lsf_ix as
appropriate. This does not find the maximum of f(x) in a mathematical sense,
it only finds the best estimate contained in the array you have created.
But I suspect you knew that.

[Richard Herring]

Re: Find the position of maximum value.

In message <4cjg51F15v99aU 1@individual.ne t>, osmium
<r124c4u102@com cast.net> writes[color=blue]
><Sunny123@ntlw orld.com> wrote:
>[color=green]
>> i am trying to find the maximum value of a function and where it occur.
>>
>> i.e there is an array
>>
>> x |y
>> =============
>> |
>> |
>> |
>> |
>> |
>> |
>>
>> and i want to find where the maximum occurs and at what value of x.
>>
>> i tried fabs but it isnt quite right.[/color]
>
>I doubt if fabs has any bearing on your problem. Try something like this.
>
>double lsf = a[0]; // lsf - largest so far, a - array
>int lsf_ix = 0;
>
>Now go through the array, starting at index = 1, modifying lsf and lsf_ix as
>appropriate. This does not find the maximum of f(x) in a mathematical sense,
>it only finds the best estimate contained in the array you have created.
>But I suspect you knew that.
>[/color]

If you're looking for a C++ solution, std::max_elemen t() will give the
position (an iterator to) the maximum element of a sequence, for a
possibly user-defined meaning of "maximum".

--
Richard Herring