<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
</head>
<body text="#000000" bgcolor="#FFFFFF">
<br>
<font face="Courier New">Daniel,<br>
<br>
Looking at the graph from your script there are two striking
things. First, your data seems to be heavily clustered at certain
regions, I mean, several points very close to each other, then a
gap without data (which is conveniently interpolated by the plot
clause), then another cluster and so on. From a statistical point
of view, each cluster <br>
</font>counts as a single point. You don't have information of what
happens between neighboring clusters.<br>
<br>
The second striking thing is that you don't seem to be using the
spline concept correctly. You are using it to approximate the same
points you already have. To make things worse, you are using
lsq_splin (a cannon to kill a fly), which is normally used to get a
simpler spline by using less breakpoints than the total number of
available points. This will normally give a smooth approximation of
data, so that the spline will not necessarily pass through any of
your points. It is used when the data set is inconsistent due to
noise or measurement errors to avoid over representing irrelevant
features. If you use it with the same number of breakpoints as the
available data, I guess you will have a spline that pass through all
the points (this will be the least-square solution since the error
will be zero), so it is the same as an ordinary spline
interpolation.<br>
<br>
The correct way to use a spline is to use it to interpolate your
data, i.e., to have much more points than the original ones, or to
have them more evenly distributed. You are representing your very
same data using a spline, so there is no smoothing. The plot
function does some interpolation job, but linearly: it connects
points with straight segments. <br>
<br>
You need to calculate more points and more evenly distributed with
your spline, but probably you'll be disappointed because the
behavior in the large gaps between data clusters may be strangewith
some odd oscillations..<br>
<br>
If you can, try to generate your data more evenly. <br>
<br>
Regards,<br>
<br>
Federico Miyara<br>
<br>
<br>
<div class="moz-cite-prefix">On 11/04/2020 21:45, Daniel Stringari
wrote:<br>
</div>
<blockquote type="cite"
cite="mid:CAAhV9xXT+q3L-JjTisk_mBHDt6_=3fmrZbsDpMPB2zn-KkFhMA@mail.gmail.com">
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<div dir="ltr">Federico,
<div><br>
</div>
<div>I am extracting the values of the vectors (vv12 and vt12)
from a logic in which it takes data from a spreadsheet that
was generated using specific software. The vectors (vv12 and
vt12) represent an efficiency curve within the torque x speed
plane, I have eleven more of these vectors that vary in size.
I believe that I do not have a role in which one depends on
the other directly. I tried to follow your first reasoning and
arrived at a routine that does not report errors but is not
smoothing my curve either, follow the routine:<br>
</div>
<div><br>
</div>
<div>
<pre style="font-family:Monospaced"><span style="color:rgb(50,185,185)">clc</span>
<span style="color:rgb(50,185,185)">clear</span>
<span style="color:rgb(0,0,0)">vt12</span> <span style="color:rgb(92,92,92)">=</span> <span style="color:rgb(74,85,219)">[</span><span style="color:rgb(188,143,143)">5350.3</span><span style="color:rgb(0,0,0)">,</span><span style="color:rgb(188,143,143)">5380.19</span><span style="color:rgb(0,0,0)">,</span><span style="color:rgb(188,143,143)">5410.08</span><span style="color:rgb(0,0,0)">,</span><span style="color:rgb(188,143,143)">5439.96</span><span style="color:rgb(0,0,0)">,</span><span style="color:rgb(188,143,143)">4149.5</span><span style="color:rgb(0,0,0)">,</span><span style="color:rgb(188,143,143)">4179.35</span><span style="color:rgb(0,0,0)">,</span><span style="color:rgb(188,143,143)">3756.57</span><span style="color:rgb(0,0,0)">,</span><span style="color:rgb(188,143,143)">3602.73</span><span style="color:rgb(0,0,0)">,</span><span style="color:rgb(188,143,143)">3568.12</span><span style="color:rgb(0,0,0)">,</span><span style="color:rgb(188,143,143)">3597.85</span><span style="color:rgb(0,0,0)">,</span><span style="color:rgb(188,143,143)">3681.91</span><span style="color:rgb(0,0,0)">,</span><span style="color:rgb(188,143,143)">3711.59</span><span style="color:rgb(0,0,0)">,</span><span style="color:rgb(188,143,143)">6143.24</span><span style="color:rgb(0,0,0)">,</span><span style="color:rgb(188,143,143)">6172.86</span><span style="color:rgb(0,0,0)">,</span><span style="color:rgb(188,143,143)">6202.49</span><span style="color:rgb(0,0,0)">,</span><span style="color:rgb(188,143,143)">6232.1</span><span style="color:rgb(74,85,219)">]</span>
<span style="color:rgb(0,0,0)">vv12</span> <span style="color:rgb(92,92,92)">=</span> <span style="color:rgb(74,85,219)">[</span><span style="color:rgb(188,143,143)">40.16</span><span style="color:rgb(0,0,0)">,</span><span style="color:rgb(188,143,143)">39.93</span><span style="color:rgb(0,0,0)">,</span><span style="color:rgb(188,143,143)">39.71</span><span style="color:rgb(0,0,0)">,</span><span style="color:rgb(188,143,143)">39.49</span><span style="color:rgb(0,0,0)">,</span><span style="color:rgb(188,143,143)">69.04</span><span style="color:rgb(0,0,0)">,</span><span style="color:rgb(188,143,143)">68.54</span><span style="color:rgb(0,0,0)">,</span><span style="color:rgb(188,143,143)">95.32</span><span style="color:rgb(0,0,0)">,</span><span style="color:rgb(188,143,143)">119.26</span><span style="color:rgb(0,0,0)">,</span><span style="color:rgb(188,143,143)">140.49</span><span style="color:rgb(0,0,0)">,</span><span style="color:rgb(188,143,143)">139.32</span><span style="color:rgb(0,0,0)">,</span><span style="color:rgb(188,143,143)">155.62</span><span style="color:rgb(0,0,0)">,</span><span style="color:rgb(188,143,143)">154.37</span><span style="color:rgb(0,0,0)">,</span><span style="color:rgb(188,143,143)">93.27</span><span style="color:rgb(0,0,0)">,</span><span style="color:rgb(188,143,143)">92.82</span><span style="color:rgb(0,0,0)">,</span><span style="color:rgb(188,143,143)">92.38</span><span style="color:rgb(0,0,0)">,</span><span style="color:rgb(188,143,143)">91.94</span><span style="color:rgb(74,85,219)">]</span>
<span style="color:rgb(0,0,0)">c</span> <span style="color:rgb(92,92,92)">=</span> <span style="color:rgb(50,185,185)">size</span> <span style="color:rgb(74,85,219)">(</span><span style="color:rgb(0,0,0)">vt12</span><span style="color:rgb(74,85,219)">)</span>
<span style="color:rgb(0,0,0)">a</span> <span style="color:rgb(92,92,92)">=</span> <span style="color:rgb(188,143,143)">1</span>
<span style="color:rgb(0,0,0)">b</span> <span style="color:rgb(92,92,92)">=</span> <span style="color:rgb(0,0,0)">c</span><span style="color:rgb(74,85,219)">(</span><span style="color:rgb(188,143,143)">2</span><span style="color:rgb(74,85,219)">)</span>
<span style="color:rgb(0,0,0)">n</span> <span style="color:rgb(92,92,92)">=</span> <span style="color:rgb(0,0,0)">c</span><span style="color:rgb(74,85,219)">(</span><span style="color:rgb(188,143,143)">2</span><span style="color:rgb(74,85,219)">)</span>
<span style="color:rgb(0,0,0)">x</span> <span style="color:rgb(92,92,92)">=</span> <span style="color:rgb(50,185,185)">linspace</span> <span style="color:rgb(74,85,219)">(</span><span style="color:rgb(0,0,0)">a</span><span style="color:rgb(0,0,0)">,</span> <span style="color:rgb(0,0,0)">b</span><span style="color:rgb(0,0,0)">,</span> <span style="color:rgb(0,0,0)">n</span><span style="color:rgb(74,85,219)">)</span>
<span style="color:rgb(74,85,219)">[</span><span style="color:rgb(0,0,0)">yvt</span><span style="color:rgb(0,0,0)">,</span><span style="color:rgb(0,0,0)">dvt</span><span style="color:rgb(74,85,219)">]</span> <span style="color:rgb(92,92,92)">=</span> <span style="color:rgb(50,185,185)">lsq_splin</span><span style="color:rgb(74,85,219)">(</span><span style="color:rgb(0,0,0)">x</span><span style="color:rgb(0,0,0)">,</span><span style="color:rgb(0,0,0)">vt12</span><span style="color:rgb(0,0,0)">,</span><span style="color:rgb(50,185,185)">linspace</span> <span style="color:rgb(74,85,219)">(</span><span style="color:rgb(0,0,0)">a</span><span style="color:rgb(0,0,0)">,</span><span style="color:rgb(0,0,0)">b</span><span style="color:rgb(0,0,0)">,</span><span style="color:rgb(0,0,0)">n</span><span style="color:rgb(74,85,219)">)</span><span style="color:rgb(74,85,219)">)</span>
<span style="color:rgb(74,85,219)">[</span><span style="color:rgb(0,0,0)">yvv</span><span style="color:rgb(0,0,0)">,</span><span style="color:rgb(0,0,0)">dvv</span><span style="color:rgb(74,85,219)">]</span> <span style="color:rgb(92,92,92)">=</span> <span style="color:rgb(50,185,185)">lsq_splin</span><span style="color:rgb(74,85,219)">(</span><span style="color:rgb(0,0,0)">x</span><span style="color:rgb(0,0,0)">,</span><span style="color:rgb(0,0,0)">vv12</span><span style="color:rgb(0,0,0)">,</span><span style="color:rgb(50,185,185)">linspace</span> <span style="color:rgb(74,85,219)">(</span><span style="color:rgb(0,0,0)">a</span><span style="color:rgb(0,0,0)">,</span><span style="color:rgb(0,0,0)">b</span><span style="color:rgb(0,0,0)">,</span><span style="color:rgb(0,0,0)">n</span><span style="color:rgb(74,85,219)">)</span><span style="color:rgb(74,85,219)">)</span>
<span style="color:rgb(0,0,0)">ys</span><span style="color:rgb(92,92,92)">=</span><span style="color:rgb(50,185,185)">interp</span><span style="color:rgb(74,85,219)">(</span><span style="color:rgb(50,185,185)">linspace</span> <span style="color:rgb(74,85,219)">(</span><span style="color:rgb(0,0,0)">a</span><span style="color:rgb(0,0,0)">,</span><span style="color:rgb(0,0,0)">b</span><span style="color:rgb(0,0,0)">,</span><span style="color:rgb(0,0,0)">n</span><span style="color:rgb(74,85,219)">)</span><span style="color:rgb(0,0,0)">,</span><span style="color:rgb(50,185,185)">linspace</span> <span style="color:rgb(74,85,219)">(</span><span style="color:rgb(0,0,0)">a</span><span style="color:rgb(0,0,0)">,</span><span style="color:rgb(0,0,0)">b</span><span style="color:rgb(0,0,0)">,</span><span style="color:rgb(0,0,0)">n</span><span style="color:rgb(74,85,219)">)</span><span style="color:rgb(0,0,0)">,</span><span style="color:rgb(0,0,0)">yvt</span><span style="color:rgb(0,0,0)">,</span><span style="color:rgb(0,0,0)">dvt</span><span style="color:rgb(74,85,219)">)</span>
<span style="color:rgb(0,0,0)">xs</span><span style="color:rgb(92,92,92)">=</span><span style="color:rgb(50,185,185)">interp</span><span style="color:rgb(74,85,219)">(</span><span style="color:rgb(50,185,185)">linspace</span> <span style="color:rgb(74,85,219)">(</span><span style="color:rgb(0,0,0)">a</span><span style="color:rgb(0,0,0)">,</span><span style="color:rgb(0,0,0)">b</span><span style="color:rgb(0,0,0)">,</span><span style="color:rgb(0,0,0)">n</span><span style="color:rgb(74,85,219)">)</span><span style="color:rgb(0,0,0)">,</span><span style="color:rgb(50,185,185)">linspace</span> <span style="color:rgb(74,85,219)">(</span><span style="color:rgb(0,0,0)">a</span><span style="color:rgb(0,0,0)">,</span><span style="color:rgb(0,0,0)">b</span><span style="color:rgb(0,0,0)">,</span><span style="color:rgb(0,0,0)">n</span><span style="color:rgb(74,85,219)">)</span><span style="color:rgb(0,0,0)">,</span><span style="color:rgb(0,0,0)">yvv</span><span style="color:rgb(0,0,0)">,</span><span style="color:rgb(0,0,0)">dvv</span><span style="color:rgb(74,85,219)">)</span>
<span style="color:rgb(174,92,176);text-decoration-line:underline">plot</span> <span style="color:rgb(74,85,219)">(</span><span style="color:rgb(0,0,0)">ys</span><span style="color:rgb(0,0,0)">,</span><span style="color:rgb(0,0,0)">xs</span><span style="color:rgb(0,0,0)">,</span><span style="color:rgb(188,143,143)">'</span><span style="color:rgb(188,143,143)">r</span><span style="color:rgb(188,143,143)">'</span><span style="color:rgb(74,85,219)">)</span>
<span style="color:rgb(174,92,176);text-decoration-line:underline">xlabel</span> <span style="color:rgb(74,85,219)">(</span><span style="color:rgb(188,143,143)">'</span><span style="color:rgb(188,143,143)">Speed (rpm)</span><span style="color:rgb(188,143,143)">'</span><span style="color:rgb(74,85,219)">)</span>
<span style="color:rgb(174,92,176);text-decoration-line:underline">ylabel</span> <span style="color:rgb(74,85,219)">(</span><span style="color:rgb(188,143,143)">'</span><span style="color:rgb(188,143,143)">Torque (Nm)</span><span style="color:rgb(188,143,143)">'</span><span style="color:rgb(74,85,219)">)</span>
<span style="color:rgb(174,92,176);text-decoration-line:underline">title</span> <span style="color:rgb(74,85,219)">(</span><span style="color:rgb(188,143,143)">'</span><span style="color:rgb(188,143,143)">Torque x speed values</span><span style="color:rgb(188,143,143)">'</span><span style="color:rgb(74,85,219)">)</span></pre>
<pre style="font-family:Monospaced">Any idea how I can proceed with my goal of smoothing the curve to use the color map later?
</pre>
<pre style="font-family:Monospaced"><span style="color:rgb(74,85,219)">
</span></pre>
<pre style="font-family:Monospaced"><span style="color:rgb(74,85,219)">
</span></pre>
</div>
</div>
<br>
<div class="gmail_quote">
<div dir="ltr" class="gmail_attr">On Sat, Apr 11, 2020 at 9:18
PM Federico Miyara <<a
href="mailto:fmiyara@fceia.unr.edu.ar"
moz-do-not-send="true">fmiyara@fceia.unr.edu.ar</a>>
wrote:<br>
</div>
<blockquote class="gmail_quote" style="margin:0px 0px 0px
0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
<div bgcolor="#FFFFFF"> <br>
Daniel,<br>
<br>
I'm afraid I was a bit confused with your application case.<br>
<br>
I assumed that there was an independent variable such as
time or other which the other two, vt12 and vv12, depend on.
If this were the case, the expected graph could be a curve
or rather a trajectory with some hysteresis.<br>
<br>
But if your data are just measurements in no particular
order of what is a functional relation of one variable
respect to the other, for instance vt12 = f(vv12), then the
approach is different. You should basically sort the
independent variable in increasing order using gsort and
apply the same sorting to the dependent variable:<br>
<br>
[x, I] = gsort(vv12,"g","i");<br>
y = vt12(I); <br>
<br>
Then you can proceed to interpolate with spline or
lsg_splin.<br>
<br>
Regards,<br>
<br>
Federico Miyara<br>
<br>
<br>
<div>On 10/04/2020 21:05, Daniel Stringari wrote:<br>
</div>
<blockquote type="cite">
<div dir="ltr">Federico,<br>
<br>
I appreciate the help. Below is a list of the code on
which I try to plot the data with Isq_splin:<br>
<br>
c = size (vt12)<br>
a = 0<br>
b = c (1) // c (1) = 16<br>
n = c (1)<br>
x = linspace (a, b, n)<br>
[y, d] = lsq_splin (vt12, vv12, x ')<br>
plot (y, d, 'r')<br>
xlabel ('Speed (rpm)')<br>
ylabel ('Torque (Nm)')<br>
title ('Torque x speed values')<br>
<br>
//vt12 = 5350.3 5380.19 5410.08 5439.96 4149.5 4179.35
3756.57 3602.73 3568.12 3597.85 3681.91 3711.59 6143.24
6172.86 6202.49 6232.1<br>
//vv12 = 40.16 39.93 39.71 39.49 69.04 68.54
95.32 119.26 140.49 139.32 155.62 154.37
93.27 92.82 92.38 91.94
<div><br>
but I'm getting the error: lsq_plin: There are not
enough points to adjust.<br>
<br>
Does anyone understand what could be wrong?<br>
</div>
</div>
<br>
<div class="gmail_quote">
<div dir="ltr" class="gmail_attr">On Wed, Apr 8, 2020 at
12:54 AM Federico Miyara <<a
href="mailto:fmiyara@fceia.unr.edu.ar"
target="_blank" moz-do-not-send="true">fmiyara@fceia.unr.edu.ar</a>>
wrote:<br>
</div>
<blockquote class="gmail_quote" style="margin:0px 0px
0px 0.8ex;border-left:1px solid
rgb(204,204,204);padding-left:1ex">
<div bgcolor="#FFFFFF"> <br>
<font face="Courier New">Daniel, <br>
<br>
You may try with lsq_spline, which unlike ordinary
spline, doesn't fit the data exactly, and it
doesn't need the data with any particular order.<br>
<br>
But trying to understand your graph, it seems that
you should parametrize two variables
independently, each one with respect to the index.
Something like this:<br>
<br>
x = [x1, x2, ..., xn]<br>
y = [y1, y2, ..., yn]<br>
<br>
Then you approximate x vs 1:n and y vs 1:n using
spline or lsq_splin. Finally you plot xs vs ys
(the smoothed versions of x and y) <br>
<br>
Regards,<br>
<br>
Federico Miyara<br>
<br>
</font><br>
<div>On 07/04/2020 22:48, Daniel Stringari wrote:<br>
</div>
<blockquote type="cite">
<pre>Good night friends,
I wrote an email before, but I believe that I was not clear in my words and
so I will write more clearly.
In this annex 1, I have the graph I am generating. Basically I am extracting
values of x (speed) and y (torque) from excel and generating vectors of x []
and y [] to plot internal lines. I want to smooth these lines, but the
functions of the scilab are only for growing points. I thought about
creating cubic splines manually, but I don't know how to do it. Can anybody
help me ?
In addition, I would like to color my chart with level colors according to
the colorbar, but I am not able to implement contour2d for this case.
thanks.
<a href="http://mailinglists.scilab.org/file/t498028/annex_1.png" target="_blank" moz-do-not-send="true"><http://mailinglists.scilab.org/file/t498028/annex_1.png></a>
--
Sent from: <a href="http://mailinglists.scilab.org/Scilab-users-Mailing-Lists-Archives-f2602246.html" target="_blank" moz-do-not-send="true">http://mailinglists.scilab.org/Scilab-users-Mailing-Lists-Archives-f2602246.html</a>
_______________________________________________
users mailing list
<a href="mailto:users@lists.scilab.org" target="_blank" moz-do-not-send="true">users@lists.scilab.org</a>
<a href="http://lists.scilab.org/mailman/listinfo/users" target="_blank" moz-do-not-send="true">http://lists.scilab.org/mailman/listinfo/users</a>
</pre>
</blockquote>
<br>
</div>
_______________________________________________<br>
users mailing list<br>
<a href="mailto:users@lists.scilab.org"
target="_blank" moz-do-not-send="true">users@lists.scilab.org</a><br>
<a
href="http://lists.scilab.org/mailman/listinfo/users"
rel="noreferrer" target="_blank"
moz-do-not-send="true">http://lists.scilab.org/mailman/listinfo/users</a><br>
</blockquote>
</div>
<br>
<fieldset></fieldset>
<pre>_______________________________________________
users mailing list
<a href="mailto:users@lists.scilab.org" target="_blank" moz-do-not-send="true">users@lists.scilab.org</a>
<a href="http://lists.scilab.org/mailman/listinfo/users" target="_blank" moz-do-not-send="true">http://lists.scilab.org/mailman/listinfo/users</a>
</pre>
</blockquote>
<br>
</div>
_______________________________________________<br>
users mailing list<br>
<a href="mailto:users@lists.scilab.org" target="_blank"
moz-do-not-send="true">users@lists.scilab.org</a><br>
<a href="http://lists.scilab.org/mailman/listinfo/users"
rel="noreferrer" target="_blank" moz-do-not-send="true">http://lists.scilab.org/mailman/listinfo/users</a><br>
</blockquote>
</div>
<br>
<fieldset class="mimeAttachmentHeader"></fieldset>
<pre class="moz-quote-pre" wrap="">_______________________________________________
users mailing list
<a class="moz-txt-link-abbreviated" href="mailto:users@lists.scilab.org" moz-do-not-send="true">users@lists.scilab.org</a>
<a class="moz-txt-link-freetext" href="http://lists.scilab.org/mailman/listinfo/users" moz-do-not-send="true">http://lists.scilab.org/mailman/listinfo/users</a>
</pre>
</blockquote>
<br>
</body>
</html>