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## Piecewise function plot

I have a problem when plotting a piecewise function.

The error is "all evaluations resulted in either an error or a complex result".

I would really appreciate if anyone can help me!

Thank-you very much.

Best Regards.

Enrico

Tags (2)
1 ACCEPTED SOLUTION

Accepted Solutions
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## Re: Piecewise function plot

The evaluation of:

F.input_rod(a)=

results in an error message "Must be scalar".

Tracing further back I find that in your definition of F.input_rod(a) you are comparing a with 10 m/s^2.

Note that a is an array, you cannot compare an array with a scalar value.

Your way out is simple: vectorize the F.input_rod(a) so that the function acts on each value, but still produces all results.

See attached.

Success!
Luc

7 REPLIES 7
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## Re: Piecewise function plot

Evaluate the variable you want to plot. If you plot e.g. y(x) and have x defined (either as a range variable or as a vector), type

y(x)=

and

x=

To see the value(s) each has. There may be NaN's in there, or imaginary numbers. Or another error occurs.

In case of an error, select the evaluation and, using the righthand mouse button, select 'trace error', and trace that error back to where it occurs.

Success!
Luc

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## Re: Piecewise function plot

Dear Luc,

Attached you find the file in .mcd format.

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## Re: Piecewise function plot

The evaluation of:

F.input_rod(a)=

results in an error message "Must be scalar".

Tracing further back I find that in your definition of F.input_rod(a) you are comparing a with 10 m/s^2.

Note that a is an array, you cannot compare an array with a scalar value.

Your way out is simple: vectorize the F.input_rod(a) so that the function acts on each value, but still produces all results.

See attached.

Success!
Luc

Highlighted

## Re: Piecewise function plot

Just a quick look (in Smath), you have some unit balance issues.

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## Re: Piecewise function plot

Where?

I don't see them. Mathcad (11) also not.

Luc

## Re: Piecewise function plot

Salve,

non puoi confrontare il vettore a con uno scalare. Il confronto con lo scalare va fatto elemento per elemento .

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## Re: Piecewise function plot

Buona giornata,

Ecco di cosa si occupa la vettorializzazione.

Successo!
Luc

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