Rank: 2264 based on 49 downloads (last 30 days) and 5 files submitted
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Isaac Mancero Mosquera

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45.65065002441406, 13.76708984375

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Professional Interests:
Signal Processing, data mining, ocean-atmosphere interaction

 

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Files Posted by Isaac View all
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29 May 2012 Depressed cubic polynomial Function to obtain the "depressed" cubic polynomial, from the general cubic form. Author: Isaac Mancero Mosquera cubic, polynomial, del ferro, roots, cubic polynomial, depressed cubic 4 11
  • 2.0
2.0 | 2 ratings
15 Jun 2011 isleap.m This file test if a given year is a normal year or a leap year. Author: Isaac Mancero Mosquera time, leap year 4 3
13 Jun 2011 Screenshot 2D Progressive Vector Diagram Sequential Vector plot. Vector components x, y are required. User can define the initial position. Author: Isaac Mancero Mosquera vector, sequence, progressive vector di..., oceanography 16 0
25 Oct 2005 Saturation Vapor Pressure Computes the saturation pressure for water vapor. Author: Isaac Mancero Mosquera chemistry, physics, saturation pressure, water vapour, water vapor, script 18 2
  • 4.33333
4.3 | 3 ratings
13 Jan 2005 Screenshot iModa Find the statistical mode of vector of data. Author: Isaac Mancero Mosquera statistics, probability, statistical mode, moda estadistica, mode 7 7
  • 4.5
4.5 | 2 ratings
Comments and Ratings by Isaac View all
Updated File Comments Rating
29 May 2012 Depressed cubic polynomial Function to obtain the "depressed" cubic polynomial, from the general cubic form. Author: Isaac Mancero Mosquera

"Thank you for the feedback. I will improve this script with a better help section and possibly a change in the name" but I'm repeating myself here.

I don't feel attacked if you criticize my program, I'm actually thankful, since programming is not my cup of tea. Also, I always welcome critics; working in Science, I have to be prepared to debunk and be debunked, there is nothing personal in it; but if we disagree in something, we have to proceed separate ways -still nothing personal in it.

I'm uploading a new version of the file soon.

28 May 2012 Depressed cubic polynomial Function to obtain the "depressed" cubic polynomial, from the general cubic form. Author: Isaac Mancero Mosquera

Attacking a mathematically silly idea is not attacking you. Stop the drama.

24 May 2012 Depressed cubic polynomial Function to obtain the "depressed" cubic polynomial, from the general cubic form. Author: Isaac Mancero Mosquera

I'll try to be more clear, for the sake of Math (I agree with all your observations regarding the programming). This two polynomials:

p(x) and q(x)=K*p(x) are different.

They even have the same roots:

p(x)=0 and q(x)=0 at the same "x".

But they are not the same as functionals, and this is best seen when wee equal them to "w" non zero:

p(x)=w & q(x)=w have not the same solutions.

Multiplying polynomials by constants is a very popular method when finding roots, or when you have the other side of the equation p(x)=w, then:

K*p(x) = K*w , still mathematically correct.

In my program, there is no a hint of any equation, is just a mapping of a polynomial from one form to other.

That's why I put a warning to the user, they might want to multiply and normalize, but they do that themselves, at their own risk; because this program does not have "w" (from p(x)=w) as an input.

24 May 2012 Depressed cubic polynomial Function to obtain the "depressed" cubic polynomial, from the general cubic form. Author: Isaac Mancero Mosquera

Sure. If that coefficient is not 1, you can't apply this method and the code is not useful. What's so wrong with that? Are you aware that Not all theorems apply when you want, but when their logic premises hold true?

If the purpose of this file was the mapping of general polynomial forms, then you'd be right and this would be a different story.

You are not reading my answer well: The depressed form can be used in a NON-EQUATION context, meaning not in a problem of the form: p(x)=0. In THAT case, it's better for the user to normalize whatever thing they want by themselves.

Please note:

Roots of p(x)=0 are unchanged by multiplication by a scalar.

Roots are changed in the case of p(x)=K. If you normalize p(x), then you should normalize K. Since K is nowhere to be found in my file, that task should be left to the user.
[Because delferro.m has a more general mapping of a polynomial unrelated to root-findings methods, so you shouldn't go around happily multiplying polynomials!].

You may like to multiply coefficients just because you want. But you are not supposed to do so in whatever context.

IF (big IF) your problem is related to findings roots, then it would be ok, but then again, there is already a built-in Matlab function to do that.

IF (again big IF) you are dealing with the functional w=p(x), you can normalize BOTH sides in your equation, or apply a more general solution, which is not exactly "divide by the coefficient of x^3", but applying another change of variable to obtain the monic trinomial form.

I hope it's clear now why this function will not divide by the coefficient of x^3 (the general mapping formulation won't do it either).

24 May 2012 Depressed cubic polynomial Function to obtain the "depressed" cubic polynomial, from the general cubic form. Author: Isaac Mancero Mosquera

Thank you for the feedback. I will improve this script with a better help section and possibly a change in the name.
-Dividing for the first coefficient after testing that it's not zero- is fine if you're going to find roots in p(x)=0. The depressed cubic for is interesting in other contexts too.
In my case, the need to invert a cubic polynomial regression: y=p(x), such that the roots of p(x)-y=0 are needed, and I prefer the user to be aware of the need of a normalization (since it will also divide potential user data "y")
There is however another more general formula, I'll include in a future version.

Comments and Ratings on Isaac's Files View all
Updated File Comment by Comments Rating
29 May 2012 Depressed cubic polynomial Function to obtain the "depressed" cubic polynomial, from the general cubic form. Author: Isaac Mancero Mosquera Mancero Mosquera, Isaac

"Thank you for the feedback. I will improve this script with a better help section and possibly a change in the name" but I'm repeating myself here.

I don't feel attacked if you criticize my program, I'm actually thankful, since programming is not my cup of tea. Also, I always welcome critics; working in Science, I have to be prepared to debunk and be debunked, there is nothing personal in it; but if we disagree in something, we have to proceed separate ways -still nothing personal in it.

I'm uploading a new version of the file soon.

28 May 2012 Depressed cubic polynomial Function to obtain the "depressed" cubic polynomial, from the general cubic form. Author: Isaac Mancero Mosquera D'Errico, John

I agree. Trying to help you when you refuse to learn, trying to show you how to make your code better is a silly thing when you refuse to do so. I should have known better.

28 May 2012 Depressed cubic polynomial Function to obtain the "depressed" cubic polynomial, from the general cubic form. Author: Isaac Mancero Mosquera Mancero Mosquera, Isaac

Attacking a mathematically silly idea is not attacking you. Stop the drama.

24 May 2012 Depressed cubic polynomial Function to obtain the "depressed" cubic polynomial, from the general cubic form. Author: Isaac Mancero Mosquera D'Errico, John

Sigh. Clearly you have not read a word of what I said, while at the same time stating that I did not read your response. Is this one of those attempts to bamboozle the reader by attacking me, claiming I have done what you are doing yourself?

I said that it makes sense to offer TWO options. One that works as you like and one that works as others will surely want. If you bothered looking at the pseudo-code I offered, you will see it does exactly that. This way the user can have it either way. You offer only ONE option, which makes your code less useful than it might be. Flexible software is useful software.

Sorry, but I see no reason to waste any more of my time on this, as you already know the truth.

24 May 2012 Depressed cubic polynomial Function to obtain the "depressed" cubic polynomial, from the general cubic form. Author: Isaac Mancero Mosquera Mancero Mosquera, Isaac

I'll try to be more clear, for the sake of Math (I agree with all your observations regarding the programming). This two polynomials:

p(x) and q(x)=K*p(x) are different.

They even have the same roots:

p(x)=0 and q(x)=0 at the same "x".

But they are not the same as functionals, and this is best seen when wee equal them to "w" non zero:

p(x)=w & q(x)=w have not the same solutions.

Multiplying polynomials by constants is a very popular method when finding roots, or when you have the other side of the equation p(x)=w, then:

K*p(x) = K*w , still mathematically correct.

In my program, there is no a hint of any equation, is just a mapping of a polynomial from one form to other.

That's why I put a warning to the user, they might want to multiply and normalize, but they do that themselves, at their own risk; because this program does not have "w" (from p(x)=w) as an input.

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