Re: partial plot

[Henry F. Mollet]

What am I missing? The two plots as per below are identical as NaN is
ignored in the second plot. I'm using
GNU Octave, version 2.1.46 (powerpc-apple-darwin6.6).
Calling Gnuplot, calling AquaTerm on Mac 10.2.8.
Henry
octave:10> plot (x,y)
octave:11> gset term aqua 1
octave:12> plot (x(!isnan(y)),y(!isnan(y)))


on 3/18/04 8:02 AM, Miquel Cabanas at address@hidden wrote:

> hi,
> 
> try using find() and isnan() to select valid items in the
> y-vector and map that selection to the x-vector. Note that
> find is not always required. For instance,
> 
> octave:1> y = [10, -20, NaN, -40, 50, NaN, 70, -80];
> octave:2> !isnan(y)
> ans =
> 
> 1  1  0  1  1  0  1  1
> 
> octave:3> y(!isnan(y))
> ans =
> 
>  10  -20  -40   50   70  -80
> 
> octave:4> x = 1:1:length(y)
> x =
> 
> 1  2  3  4  5  6  7  8
> 
> octave:5> x(!isnan(y))
> ans =
> 
> 1  2  4  5  7  8
> 
> octave:6> plot( x(!isnan(y), y(!isnan(y) )
> 
> 
> Miquel
> 
> 
> 
> On Thu, Mar 18, 2004 at 07:52:56AM -0600, Pascal A. Dupuis wrote:
>> After some computation I obtain a matrix of values I wish to plot. But
>> some of the values are not reliable, and I can define a logical matrix
>> (matrix of ones and zeros) telling if the corresponding result is
>> valid or not.
>> 
>> I would like to have a plot containing only the valid values.
>> I tried:
>>   - plot(value(Is_valid)) -> this does not work as the result is a
>>   column vector
>>   - Is_nvalid = Is_valid == 0; value(Is_nvalid)=NA -> but this does
>>   not work either, as NA values are strangely intepolated.
>> 
>> What I would like is that values flagged as invalid are not plotted,
>> yet the x-abscissa is incremented by one unit. For instance,
>> plot([-2 NA -1]) should join the pair (1, -2) and (3, -1) instead of
>> (1, -2) and (2, -1). Is there some way to achieve this other than
>> plotting the matrix rows by rows ?
>> 



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