       Re: strange error

• To: mathgroup at smc.vnet.net
• Subject: [mg122270] Re: strange error
• From: DrMajorBob <btreat1 at austin.rr.com>
• Date: Sun, 23 Oct 2011 06:22:31 -0400 (EDT)
• Delivered-to: l-mathgroup@mail-archive0.wolfram.com
• References: <201110221009.GAA29789@smc.vnet.net>
• Reply-to: drmajorbob at yahoo.com

```Here are three versions that work:

test1[m_?NumericQ] := Module[{ret},
If[m < 100, ret = 2 m];
If[100 <= m <= 200, ret = 200 + (m - 100)];
If[200 < m, ret = 300 + 0.5 (m - 200)];
N@ret
]

test2[m_] =
Piecewise[{{2 m, m < 100}, {200 + (m - 100),
100 <= m <= 200}, {300 + 0.5 (m - 200), 200 < m}}];

test3[m_] = Which[m < 100, 2 m,
100 <= m <= 200, 200 + (m - 100),
200 < m, 300 + 0.5 (m - 200),
True, 0];

FindRoot[test1@m == 250, {m, 150, 0, 300}]
FindRoot[test2@m == 250, {m, 150, 0, 300}]
FindRoot[test3@m == 250, {m, 150, 0, 300}]

{m -> 150.}

{m -> 150.}

{m -> 150.}

The original style is a very bad habit.

Bobby

On Sat, 22 Oct 2011 05:09:04 -0500, Klemen Dovrtel
<klemen_dovrtel at yahoo.com> wrote:

> Hello everybody,
>
> I defined a simple function that is composed of three functions, each
> for different range of argument/variable. The function was composed
> using If[] conditions. The problem is that i can't FindRoot of this
> composed function. I get an error "the function value is not a list of
> numbers with dimensions {1}", which is not true. Any idea how can i
> solve this?
>
>
> Mathematica print screen:
>
> http://www.shrani.si/f/t/vo/3jLzgMiy/prtscr.jpg
>
> Best Regards
> Klemen

--
DrMajorBob at yahoo.com

```

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