## 35 Reputation

0 years, 335 days

## Why does Determinant function return flo...

Maple 2018

Hi,

I'm trying to implement Kernal PCA, I've got a large kernal matrix for which I have checked the elements are of floating point type, however when I try to run the Determinant operation on the matrix all of the coefficients say float(undefined).

In the same worksheet, there I have implemented the standard PCA routine, for which the determinant operation works fine. You can see this operation functioning corrrectly in it's testing section.

If anyone has any idea why this might be occuring I'd be really grateful for some advice.

Thanks

FUML.mw

## How to Subsitute Animation Parameter int...

Maple

Hi guys

I've created a joint display which plots a spacecurve and an arrow which represents the tangent to the curve:

I've written this in the animation format so I can move the tangent arrow along the curve, however when I replace

```arrow(subs(s=0,p),subs(s=0,ptan),width=0.3,length=4)
```

with

```arrow(subs(s=A,p),subs(s=A,ptan),width=0.3,length=4)
```

I get the error:

Error, (in Plot:-AnalyzeData:-StandardizeData) points cannot be converted to floating-point values

I have tried animating the arrow alone(see below) and this works fine, so the problem is coming from try to pass the animation parameter A into the display array of multiple plots.

DG.mw

Thanks

## Declare Variable Domain...

Maple

Hello,

I currently have

And was wondering if there's a way to declare x as a real so that this evaluates to 1?

## Broken Piecewise Function...

Maple

Yo I have fit a surface to a curve using polynomial regression:

(It's only supposed to be fit for negative t domain)

Now I've attempted to cap this function off at 0, using a piecewise function of the original:

Which when I print, looks somewhat about right:

Sorry it's so hard to see but you get the idea. The problem is that this seems to set the whole function to 0, rather than just the bits that should clip:

The piecwise function seems to be evaluating the fN>0 condition to true for all input values p,t, rather than substituing the new input values into the original function fN, and then evaluating the condition for every point, not really sure what the problem is, would appreciate some help!

## Categoric Variable Plot...

Maple

Forgive me for asking but I can't seem to find it in the docs, how do I create a plot which has a categoric variable rather than just real ones? i.e. having it print string labels along one axis rather than integers..

Also hoping this is possible on a 3D graph where each category is associated with 2 real values, i.e. a slice of the 3D plot...

Thanks

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