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Piece Wise Linear Fitting

Another dawning while doodling at the beauty shop...

... a way to join line segments easily to form PWL's, while maintaining all derivatives at the joining points.

(Using my TANH version of greater than, less than... I'm working on refining its coefficients to match segment slopes so there's no "peaking" :-) ...Jim Thompson

-- | James E.Thompson | mens | | Analog Innovations | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | San Tan Valley, AZ 85142 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at

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| 1962 | I love to cook with wine. Sometimes I even put it in the food.

Reply to
Jim Thompson
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Try regular hyperbolae. The derivatives exist... just take care not to divide by zero (which can happen with tanh too, and probably at analogous points, for analogous reasons).

Tim

-- Seven Transistor Labs Electrical Engineering Consultation Website:

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"Jim Thompson" wrote in message news: snipped-for-privacy@4ax.com...

Reply to
Tim Williams

Division by zero computing tanh of a real number? That would take talent. Care to elaborate?

Cheers

Phil Hobbs

Reply to
Phil Hobbs

Maybe it was atanh, but it's not the function of a real number, it's the derivative that causes problems. Certain people here swear by this for continuous limiter functions in SPICE, but I've found they can go batty rather often.

Incidentally, The Internet doesn't know that degenerate circuits aren't the only condition that can create singular matrices.

Tim

--
Seven Transistor Labs 
Electrical Engineering Consultation 
Website: http://seventransistorlabs.com
Reply to
Tim Williams

All derivatives of TANH exist and don't go "batty". You must be thinking of some other function. ...Jim Thompson

--
| James E.Thompson                                 |    mens     | 
| Analog Innovations                               |     et      | 
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    | 
| San Tan Valley, AZ 85142   Skype: Contacts Only  |             | 
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  | 
| E-mail Icon at http://www.analog-innovations.com |    1962     | 
              
I love to cook with wine.     Sometimes I even put it in the food.
Reply to
Jim Thompson

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