Databases
StackOverflow2013
Postsdbo
PO
 

Note that there are some explanatory texts on larger screens.

plurals
  1. PO
    primarykey
    data
    text
    <p>Based on the comment from Robert Kern, I have removed my previous answer. Here are the constraints as continuous functions:</p> <pre><code>b1 = lambda x: x[4]-x[0] if x[4]&lt;1.2*x[0] else 1.4*x[0]-x[4] b2 = lambda x: x[5]-x[1] if x[5]&lt;1.2*x[1] else 1.4*x[1]-x[5] b3 = lambda x: x[2]-x[3] </code></pre> <p>Note: Python 2.5 or greater is required for this syntax.<sup>1</sup></p> <p>To get the constraint <code>a&lt;=e&lt;=1.4*a</code>, note that <code>1.2*a</code> is the halfway point between <code>a</code> and <code>1.4*a</code>.</p> <p>Below this point, that is, all <code>e&lt;1.2*a</code>, we use the continuous function <code>e-a</code>. Thus the overall constraint function is negative when <code>e&lt;a</code>, handling the lower out-of-bounds condition, zero on the lower boundary <code>e==a</code>, and then positive for <code>e&gt;a</code> up to the halfway point.</p> <p>Above the halfway point, that is, all <code>e&gt;1.2*a</code>, we use instead the continuous function <code>1.4*a-e</code>. This means the overall constraint function is is negative when <code>e&gt;1.4*a</code>, handling the upper out-of-bounds condition, zero on the upper boundary <code>e==1.4*a</code>, and then positive when <code>e&lt;1.4*a</code>, down to the halfway point.</p> <p>At the halfway point, where <code>e==1.2*a</code>, both functions have the same value. This means that the overall function is continuous.</p> <p>Reference: <a href="http://projects.scipy.org/scipy/attachment/ticket/565/slsqp.py" rel="nofollow noreferrer">documentation for <code>ieqcons</code></a>.</p> <p><sup><strong>1</strong> - Here is pre-Python 2.5 syntax: <code>b1 = lambda x: (1.4*x[0]-x[4], x[4]-x[0])[x[4]&lt;1.2*x[0]]</code></sup></p>
    singulars
    1. This table or related slice is empty.
    1. POUsing lambda for a constraint function
      singulars
      1. PTQuestion
    1. PTAnswer
    1. USsystem PAUSE
    1. USsystem PAUSE
    plurals
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. POUsing lambda for a constraint function
      singulars
      1. PTQuestion
    1. This table or related slice is empty.
    1. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTUpMod
    1. CONo, this will not work. The constraint functions should be continuous as much as possible, >0 when they are satisfied, <0 when they are not, and ==0 when they are precisely on the boundary.
      singulars
      1. PO
      1. USRobert Kern
    2. COsystem Pause, as Robert says function has to continuous. so i have made lambda x: ([1.4*x[0] - x[0]]), ie.,lambda x:(max-min). But what am i made is correct or not i don't know.
      singulars
      1. PO
      1. This table or related slice is empty.
    3. CO@pear, I don't think that can be correct, as it does not use *e* (aka `x[4]`) at all in the expression. That expression is equivalent to `1.4*a - a` which is always going to have the value `0.4a`.
      singulars
      1. PO
      1. USsystem PAUSE
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload