<html>
<head>
<meta content="text/html; charset=windows-1252"
http-equiv="Content-Type">
</head>
<body bgcolor="#FFFFFF" text="#000000">
<div class="moz-cite-prefix">Samuel,<br>
<br>
Thanks for the response. While the example, I showed is linear,
the equations I want to solve are not. I am thinking I need<br>
a third function which returns a vector. Am I on the right track?<br>
<br>
Bob<br>
<br>
On 8/28/2016 4:31 PM, Samuel Gougeon wrote:<br>
</div>
<blockquote cite="mid:57C34A34.2030801@free.fr" type="cite">
<meta content="text/html; charset=windows-1252"
http-equiv="Content-Type">
<div class="moz-cite-prefix">Le 28/08/2016 22:03, Robert Sherry a
écrit :<br>
</div>
<blockquote
cite="mid:4a491463-618d-a1e4-4570-0d4ea4fcd8e3@comcast.net"
type="cite">
<meta http-equiv="content-type" content="text/html;
charset=windows-1252">
<span style="color: rgb(0, 0, 0); font-family: Verdana, Geneva,
Helvetica, Arial, sans-serif; font-size: 13.44px; font-style:
normal; font-variant-ligatures: normal; font-variant-caps:
normal; font-weight: normal; letter-spacing: normal;
line-height: normal; orphans: 2; text-align: start;
text-indent: 0px; text-transform: none; white-space: normal;
widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px;
display: inline !important; float: none; background-color:
rgb(255, 255, 255);">I defined the following two functions:<span
class="Apple-converted-space"> </span></span><br
style="color: rgb(0, 0, 0); font-family: Verdana, Geneva,
Helvetica, Arial, sans-serif; font-size: 13.44px; font-style:
normal; font-variant-ligatures: normal; font-variant-caps:
normal; font-weight: normal; letter-spacing: normal;
line-height: normal; orphans: 2; text-align: start;
text-indent: 0px; text-transform: none; white-space: normal;
widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px;
background-color: rgb(255, 255, 255);">
<br style="color: rgb(0, 0, 0); font-family: Verdana, Geneva,
Helvetica, Arial, sans-serif; font-size: 13.44px; font-style:
normal; font-variant-ligatures: normal; font-variant-caps:
normal; font-weight: normal; letter-spacing: normal;
line-height: normal; orphans: 2; text-align: start;
text-indent: 0px; text-transform: none; white-space: normal;
widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px;
background-color: rgb(255, 255, 255);">
<span style="color: rgb(0, 0, 0); font-family: Verdana, Geneva,
Helvetica, Arial, sans-serif; font-size: 13.44px; font-style:
normal; font-variant-ligatures: normal; font-variant-caps:
normal; font-weight: normal; letter-spacing: normal;
line-height: normal; orphans: 2; text-align: start;
text-indent: 0px; text-transform: none; white-space: normal;
widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px;
display: inline !important; float: none; background-color:
rgb(255, 255, 255);">function [z]=f(x,y)<span
class="Apple-converted-space"> </span></span><br
style="color: rgb(0, 0, 0); font-family: Verdana, Geneva,
Helvetica, Arial, sans-serif; font-size: 13.44px; font-style:
normal; font-variant-ligatures: normal; font-variant-caps:
normal; font-weight: normal; letter-spacing: normal;
line-height: normal; orphans: 2; text-align: start;
text-indent: 0px; text-transform: none; white-space: normal;
widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px;
background-color: rgb(255, 255, 255);">
<span style="color: rgb(0, 0, 0); font-family: Verdana, Geneva,
Helvetica, Arial, sans-serif; font-size: 13.44px; font-style:
normal; font-variant-ligatures: normal; font-variant-caps:
normal; font-weight: normal; letter-spacing: normal;
line-height: normal; orphans: 2; text-align: start;
text-indent: 0px; text-transform: none; white-space: normal;
widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px;
display: inline !important; float: none; background-color:
rgb(255, 255, 255);">z = x + y - 8<span
class="Apple-converted-space"> </span></span><br
style="color: rgb(0, 0, 0); font-family: Verdana, Geneva,
Helvetica, Arial, sans-serif; font-size: 13.44px; font-style:
normal; font-variant-ligatures: normal; font-variant-caps:
normal; font-weight: normal; letter-spacing: normal;
line-height: normal; orphans: 2; text-align: start;
text-indent: 0px; text-transform: none; white-space: normal;
widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px;
background-color: rgb(255, 255, 255);">
<span style="color: rgb(0, 0, 0); font-family: Verdana, Geneva,
Helvetica, Arial, sans-serif; font-size: 13.44px; font-style:
normal; font-variant-ligatures: normal; font-variant-caps:
normal; font-weight: normal; letter-spacing: normal;
line-height: normal; orphans: 2; text-align: start;
text-indent: 0px; text-transform: none; white-space: normal;
widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px;
display: inline !important; float: none; background-color:
rgb(255, 255, 255);">endfunction<span
class="Apple-converted-space"> </span></span><br
style="color: rgb(0, 0, 0); font-family: Verdana, Geneva,
Helvetica, Arial, sans-serif; font-size: 13.44px; font-style:
normal; font-variant-ligatures: normal; font-variant-caps:
normal; font-weight: normal; letter-spacing: normal;
line-height: normal; orphans: 2; text-align: start;
text-indent: 0px; text-transform: none; white-space: normal;
widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px;
background-color: rgb(255, 255, 255);">
<br style="color: rgb(0, 0, 0); font-family: Verdana, Geneva,
Helvetica, Arial, sans-serif; font-size: 13.44px; font-style:
normal; font-variant-ligatures: normal; font-variant-caps:
normal; font-weight: normal; letter-spacing: normal;
line-height: normal; orphans: 2; text-align: start;
text-indent: 0px; text-transform: none; white-space: normal;
widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px;
background-color: rgb(255, 255, 255);">
<span style="color: rgb(0, 0, 0); font-family: Verdana, Geneva,
Helvetica, Arial, sans-serif; font-size: 13.44px; font-style:
normal; font-variant-ligatures: normal; font-variant-caps:
normal; font-weight: normal; letter-spacing: normal;
line-height: normal; orphans: 2; text-align: start;
text-indent: 0px; text-transform: none; white-space: normal;
widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px;
display: inline !important; float: none; background-color:
rgb(255, 255, 255);">function [z]=g(x,y)<span
class="Apple-converted-space"> </span></span><br
style="color: rgb(0, 0, 0); font-family: Verdana, Geneva,
Helvetica, Arial, sans-serif; font-size: 13.44px; font-style:
normal; font-variant-ligatures: normal; font-variant-caps:
normal; font-weight: normal; letter-spacing: normal;
line-height: normal; orphans: 2; text-align: start;
text-indent: 0px; text-transform: none; white-space: normal;
widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px;
background-color: rgb(255, 255, 255);">
<span style="color: rgb(0, 0, 0); font-family: Verdana, Geneva,
Helvetica, Arial, sans-serif; font-size: 13.44px; font-style:
normal; font-variant-ligatures: normal; font-variant-caps:
normal; font-weight: normal; letter-spacing: normal;
line-height: normal; orphans: 2; text-align: start;
text-indent: 0px; text-transform: none; white-space: normal;
widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px;
display: inline !important; float: none; background-color:
rgb(255, 255, 255);">z = 2*x + y - 8<span
class="Apple-converted-space"> </span></span><br
style="color: rgb(0, 0, 0); font-family: Verdana, Geneva,
Helvetica, Arial, sans-serif; font-size: 13.44px; font-style:
normal; font-variant-ligatures: normal; font-variant-caps:
normal; font-weight: normal; letter-spacing: normal;
line-height: normal; orphans: 2; text-align: start;
text-indent: 0px; text-transform: none; white-space: normal;
widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px;
background-color: rgb(255, 255, 255);">
<span style="color: rgb(0, 0, 0); font-family: Verdana, Geneva,
Helvetica, Arial, sans-serif; font-size: 13.44px; font-style:
normal; font-variant-ligatures: normal; font-variant-caps:
normal; font-weight: normal; letter-spacing: normal;
line-height: normal; orphans: 2; text-align: start;
text-indent: 0px; text-transform: none; white-space: normal;
widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px;
display: inline !important; float: none; background-color:
rgb(255, 255, 255);">endfunction<span
class="Apple-converted-space"> </span></span><br
style="color: rgb(0, 0, 0); font-family: Verdana, Geneva,
Helvetica, Arial, sans-serif; font-size: 13.44px; font-style:
normal; font-variant-ligatures: normal; font-variant-caps:
normal; font-weight: normal; letter-spacing: normal;
line-height: normal; orphans: 2; text-align: start;
text-indent: 0px; text-transform: none; white-space: normal;
widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px;
background-color: rgb(255, 255, 255);">
<br style="color: rgb(0, 0, 0); font-family: Verdana, Geneva,
Helvetica, Arial, sans-serif; font-size: 13.44px; font-style:
normal; font-variant-ligatures: normal; font-variant-caps:
normal; font-weight: normal; letter-spacing: normal;
line-height: normal; orphans: 2; text-align: start;
text-indent: 0px; text-transform: none; white-space: normal;
widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px;
background-color: rgb(255, 255, 255);">
<span style="color: rgb(0, 0, 0); font-family: Verdana, Geneva,
Helvetica, Arial, sans-serif; font-size: 13.44px; font-style:
normal; font-variant-ligatures: normal; font-variant-caps:
normal; font-weight: normal; letter-spacing: normal;
line-height: normal; orphans: 2; text-align: start;
text-indent: 0px; text-transform: none; white-space: normal;
widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px;
display: inline !important; float: none; background-color:
rgb(255, 255, 255);">I then wanted to find the roots of the
two functions (equations). That is, I want a pair of numbers
(a,b)<span class="Apple-converted-space"> </span></span><br
style="color: rgb(0, 0, 0); font-family: Verdana, Geneva,
Helvetica, Arial, sans-serif; font-size: 13.44px; font-style:
normal; font-variant-ligatures: normal; font-variant-caps:
normal; font-weight: normal; letter-spacing: normal;
line-height: normal; orphans: 2; text-align: start;
text-indent: 0px; text-transform: none; white-space: normal;
widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px;
background-color: rgb(255, 255, 255);">
<span style="color: rgb(0, 0, 0); font-family: Verdana, Geneva,
Helvetica, Arial, sans-serif; font-size: 13.44px; font-style:
normal; font-variant-ligatures: normal; font-variant-caps:
normal; font-weight: normal; letter-spacing: normal;
line-height: normal; orphans: 2; text-align: start;
text-indent: 0px; text-transform: none; white-space: normal;
widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px;
display: inline !important; float: none; background-color:
rgb(255, 255, 255);">such that f(a,b) = g(a,b) = 0. So, I
found the function fsolve in the documentation of Scilab which
I believe will do what I want. So, I ran the following
command:<span class="Apple-converted-space"> </span></span><br
style="color: rgb(0, 0, 0); font-family: Verdana, Geneva,
Helvetica, Arial, sans-serif; font-size: 13.44px; font-style:
normal; font-variant-ligatures: normal; font-variant-caps:
normal; font-weight: normal; letter-spacing: normal;
line-height: normal; orphans: 2; text-align: start;
text-indent: 0px; text-transform: none; white-space: normal;
widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px;
background-color: rgb(255, 255, 255);">
<span style="color: rgb(0, 0, 0); font-family: Verdana, Geneva,
Helvetica, Arial, sans-serif; font-size: 13.44px; font-style:
normal; font-variant-ligatures: normal; font-variant-caps:
normal; font-weight: normal; letter-spacing: normal;
line-height: normal; orphans: 2; text-align: start;
text-indent: 0px; text-transform: none; white-space: normal;
widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px;
display: inline !important; float: none; background-color:
rgb(255, 255, 255);"> fsolve([0;0],f,g)<span
class="Apple-converted-space"> </span></span><br
style="color: rgb(0, 0, 0); font-family: Verdana, Geneva,
Helvetica, Arial, sans-serif; font-size: 13.44px; font-style:
normal; font-variant-ligatures: normal; font-variant-caps:
normal; font-weight: normal; letter-spacing: normal;
line-height: normal; orphans: 2; text-align: start;
text-indent: 0px; text-transform: none; white-space: normal;
widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px;
background-color: rgb(255, 255, 255);">
<span style="color: rgb(0, 0, 0); font-family: Verdana, Geneva,
Helvetica, Arial, sans-serif; font-size: 13.44px; font-style:
normal; font-variant-ligatures: normal; font-variant-caps:
normal; font-weight: normal; letter-spacing: normal;
line-height: normal; orphans: 2; text-align: start;
text-indent: 0px; text-transform: none; white-space: normal;
widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px;
display: inline !important; float: none; background-color:
rgb(255, 255, 255);">and it produced the following error:<span
class="Apple-converted-space"> </span></span><br
style="color: rgb(0, 0, 0); font-family: Verdana, Geneva,
Helvetica, Arial, sans-serif; font-size: 13.44px; font-style:
normal; font-variant-ligatures: normal; font-variant-caps:
normal; font-weight: normal; letter-spacing: normal;
line-height: normal; orphans: 2; text-align: start;
text-indent: 0px; text-transform: none; white-space: normal;
widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px;
background-color: rgb(255, 255, 255);">
<span style="color: rgb(0, 0, 0); font-family: Verdana, Geneva,
Helvetica, Arial, sans-serif; font-size: 13.44px; font-style:
normal; font-variant-ligatures: normal; font-variant-caps:
normal; font-weight: normal; letter-spacing: normal;
line-height: normal; orphans: 2; text-align: start;
text-indent: 0px; text-transform: none; white-space: normal;
widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px;
display: inline !important; float: none; background-color:
rgb(255, 255, 255);"> Undefined variable: y<span
class="Apple-converted-space"> </span></span><br
style="color: rgb(0, 0, 0); font-family: Verdana, Geneva,
Helvetica, Arial, sans-serif; font-size: 13.44px; font-style:
normal; font-variant-ligatures: normal; font-variant-caps:
normal; font-weight: normal; letter-spacing: normal;
line-height: normal; orphans: 2; text-align: start;
text-indent: 0px; text-transform: none; white-space: normal;
widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px;
background-color: rgb(255, 255, 255);">
<span style="color: rgb(0, 0, 0); font-family: Verdana, Geneva,
Helvetica, Arial, sans-serif; font-size: 13.44px; font-style:
normal; font-variant-ligatures: normal; font-variant-caps:
normal; font-weight: normal; letter-spacing: normal;
line-height: normal; orphans: 2; text-align: start;
text-indent: 0px; text-transform: none; white-space: normal;
widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px;
display: inline !important; float: none; background-color:
rgb(255, 255, 255);"> at line 2 of function f
called by : <span class="Apple-converted-space"> </span></span><br
style="color: rgb(0, 0, 0); font-family: Verdana, Geneva,
Helvetica, Arial, sans-serif; font-size: 13.44px; font-style:
normal; font-variant-ligatures: normal; font-variant-caps:
normal; font-weight: normal; letter-spacing: normal;
line-height: normal; orphans: 2; text-align: start;
text-indent: 0px; text-transform: none; white-space: normal;
widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px;
background-color: rgb(255, 255, 255);">
<span style="color: rgb(0, 0, 0); font-family: Verdana, Geneva,
Helvetica, Arial, sans-serif; font-size: 13.44px; font-style:
normal; font-variant-ligatures: normal; font-variant-caps:
normal; font-weight: normal; letter-spacing: normal;
line-height: normal; orphans: 2; text-align: start;
text-indent: 0px; text-transform: none; white-space: normal;
widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px;
display: inline !important; float: none; background-color:
rgb(255, 255, 255);"> fsolve([0;0],f,g)<span
class="Apple-converted-space"> </span></span><br
style="color: rgb(0, 0, 0); font-family: Verdana, Geneva,
Helvetica, Arial, sans-serif; font-size: 13.44px; font-style:
normal; font-variant-ligatures: normal; font-variant-caps:
normal; font-weight: normal; letter-spacing: normal;
line-height: normal; orphans: 2; text-align: start;
text-indent: 0px; text-transform: none; white-space: normal;
widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px;
background-color: rgb(255, 255, 255);">
<span style="color: rgb(0, 0, 0); font-family: Verdana, Geneva,
Helvetica, Arial, sans-serif; font-size: 13.44px; font-style:
normal; font-variant-ligatures: normal; font-variant-caps:
normal; font-weight: normal; letter-spacing: normal;
line-height: normal; orphans: 2; text-align: start;
text-indent: 0px; text-transform: none; white-space: normal;
widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px;
display: inline !important; float: none; background-color:
rgb(255, 255, 255);">I do not understand this error and I am
hoping that somebody can tell me what I am doing wrong.<span
class="Apple-converted-space"> </span></span><br
style="color: rgb(0, 0, 0); font-family: Verdana, Geneva,
Helvetica, Arial, sans-serif; font-size: 13.44px; font-style:
normal; font-variant-ligatures: normal; font-variant-caps:
normal; font-weight: normal; letter-spacing: normal;
line-height: normal; orphans: 2; text-align: start;
text-indent: 0px; text-transform: none; white-space: normal;
widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px;
background-color: rgb(255, 255, 255);">
</blockquote>
<br>
You problem is linear. So there are simpler solutions than
fsolve() that is useful for systems of non-linear equations.<br>
Your system is equivalent to the matrix equation<br>
[1 1 ; 2 1]*X = [ 8 ; 8] with X = [x ; y]<br>
Let set<br>
A = [1 1 ; 2 1] ;<br>
// and <br>
b = [ 8 ; 8];<br>
// from A*X = b, we get X with<br>
X = A\b<br>
<tt>--> X = A\b</tt><tt><br>
</tt><tt> X = </tt><tt><br>
</tt><tt> 0.</tt><tt><br>
</tt><tt> 8.</tt><tt><br>
</tt>that means { x=0, y=8 }<br>
<br>
Regards<br>
Samuel<br>
<br>
<br>
<fieldset class="mimeAttachmentHeader"></fieldset>
<br>
<pre wrap="">_______________________________________________
users mailing list
<a class="moz-txt-link-abbreviated" href="mailto:users@lists.scilab.org">users@lists.scilab.org</a>
<a class="moz-txt-link-freetext" href="http://lists.scilab.org/mailman/listinfo/users">http://lists.scilab.org/mailman/listinfo/users</a>
</pre>
</blockquote>
<p><br>
</p>
</body>
</html>