Weekend Cat Blogging #147

Luna and I welcome everyone to the Weekend Cat Blogging #147 Round Up!

We are dedicating WCB this weekend to our friend Upsie, who passed away this week. Upsie and Sher were among the first to welcome us to Weekend Cat Blogging, and she will be missed. Please visit What Did You Eat to offer them your thoughts.

Kashim, Othello and Astrid are also dedicating their WCB to Upsie and Sher, and have this wonderful graphic.

Artsy Catsy is having a 200th post contest. They are putting together some surprises for the kitty who comes closest to guessing the date and time (US Eastern Daylight Time). And, speaking of March 31, that's the last day of their March Madness Fundraisers for Moki, Project H.A.M. and Lilly Lu.

Bustopher and Harmon are waiting for spring, and someone (Bustopher) is often stir crazy??one day it?s warm, then it?s cold?.its warm again and then the mornings are cold and then it?s a warm afternoon and then. However, Harmon is taking it all??.well, like Harmon does. They are now at their new blog icanhaspnutbutr.

Some springtime activity at CorgiFeathers. Zandakitty is having a little trouble with her solo kickboxing. Welcome to WCB!

Our friend whaleshaman of JellyPizza reminds us that kitties love boxes. “Purrfect for little places to hide & feel sad & be happy at the same time, too, for having known Upsie.” And for having known Upsie, a tribute: “A Silence Fell”.

Mind of Mog has another shot of Bazel because he is just so cute.

Andrée at meeyauw has LOL Cat Bible: Lectionary Readings for the Second Sunday of Easter. “See where bad kittehs go, LOL Cat Bible is on Twitter, 60% of the LOL Cat Bible is translated now, and a papercraft that you can make at home!

Spring is coming at Music and Cats, and a neighbor cat is out guarding his garden. Turns out he was quite a friendly cat (and handsome as well), happy to come over and greet passers by and purr, while still “standing his ground.”

A brief scare last week at Life from a Cat's Perspective when Samantha got out and was lost! Fortunately, she came home safely. Here we see her looking contrite after causing so much worry for her family and friends.

Save the environment…help a cat… Moki's family is holding a recycle-your-old-electronics drive to help raise money for Lilly Lu, Moki and other kitties in the cat blogosphere who need finanical assistance with their medical bills. Visit their site for more details, it's free to participate.

Fridolin is grief-stricken as he has just learnt about Upsie's sudden passing away. He shares his feelings, and a secret, at Rosa's Yummy Yums.

Kitikata-san also misses Upsie, “you were the coolest cat, and I am sad you are gone. Meows, purrs and headbutts to Sher. I am so sorry.

Want see a real brat? Well, head over to the BengalBrats.com to read about SonnyBob's “nasty behavior.” This includes continued persecution of the resident Great Dane. SirWoody attempts negotiations (but fails) at Pet's Garden Blog. The Bengal Brats are also hosting Bad Kitty Cats Festival of Chaos this Sunday.

Carnival of the Cats will be happening this Sunday at Nikita's Place. And next Sunday, it will be here at CatSynth!

We'll continue to post throughout the weekend (and into Monday morning), so if you want to participate, please leave a comment or contact us.

Hosting Weekend Cat Blogging #147

We're hosting Weekend Cat Blogging #147 here at CatSynth this weekend!
Even though we're still surrounded by half-unpacked boxes, bare walls and disorganized shelves, we're happy to be hosting our first “San Francisco edition”, and looking forward to a big round-up.

To participate, leave a comment on this post, or contact us.

Note: There is a bug in our comment system that blocks a very small number of people. We'll try and fix this as soon as we can, but if you have trouble, please contact us.


Be sure to check out the other weekend cat-blogging events.

The Bad Kitty Cats Festival of Chaos is being hosted by The Brats at Pet's Garden Blog.

The Carnival of the Cats will be hosted this Sunday at Nikita's place

And the Friday Ark is at the modulator.

Walking in San Francisco

This morning, I find myself in the Castro – or is it the Mission District, it is increasingly ambiguous where one ends and the other begins. Some thoughtful person took it upon himself to suggest that I would go blind using my laptop. He of course said this while puffing away on a cigarette. I ask you who is taking the bigger health risk here?

One activity that almost no one disputes as being healthy is walking. And San Francisco is a great walking city. For one, it is quite small, and the areas of the city one would actually want to visit are even smaller. So instead of presenting another highway article this weekend, we at CatSynth will share a little walking tour of our new hometown, weaving in other articles from the past month. The approximate path is indicated in the map below:


[click to enlarge]

Heading north from CatSynth HQ through the South of Market neighborhood, we quickly arrive at Yerba Buena Gardens, next to the San Francisco Museum of Modern Art, which I wrote about a few weeks ago. It still amazes me how close this is to home now, just a short walk if one knows the short cuts underneath the highway. I continue to enjoy the gritty industrial nature of the area as typified in these photos from Gabriele Basilico.

After crossing the welcome greenery Yerba Buena Gardens, one is only a block from Market Street, San Francisco's main commercial thoroughfare through downtown and the Financial District The main activity on Market Street is attempting to cross it. Though it is also home to the Luggage Store, where I performed in February and will play again in May.

The side streets of the Financial District are strangely quiet on the weekend as one continues north, towards the Jackson Square neighborhood This is the oldest part of the city, with old three-story iron and brick buildings crowding narrow alleyways that typify nineteenth century urban areas. Some of the buildings here do in fact date back to the nineteenth century, having survived the 1906 earthquake and fire. However, right around the neighborhood park are a bunch of low-rise residences that look more like the 1970s than the 1870s, and a bit surreal given the surroundings. Nestled in the old (and not-so-old) buildings and alleyways are furniture and interior-design stores that are a bit on the expensive side, as well some restaurants and watering holes, art galleries, and the hair salon at which I had an appointment.

North and west of Jackson Square, one weaves in and out of Chinatown, which is hard to miss, on the way to North Beach. This is a typical place to end up for food and drink, and I was headed to a pub on Washington Square park that was recommended to me. They had an unusual selection of beers, including a chipotle ale. I cannot eat or drink and do nothing else, and having not brought my computer or a book on this trip, I did something I normally wouldn't do and got something to read from City Lights Bookstore: a small book of surrealist games from the 1920s. This might actually be useful, but in any case it seemed to go well with chipotle ale.

If one plans to do any walking in San Francisco, one has to be prepared for hills, either scaling them or taking extra-long routes around them. North Beach in particular is surrounded by hills, and from the Washington Square, one can head east on Union Street towards Telegraph Hill (which is featured in many a film, including the recent Wild Parrots of Telegraph Hill) and then down to the bay. Or one can head south along Powell Street to Nob Hill. As you climb Powell, you can watch tourists waiting at cable car stops.

This is not a short walking trip, a few hours in all (including stops). One can try to catch a bus or a streetcar, but my experience has been that one can walk several blocks in the time it takes to wait for a bus, so unless it is one that is frequent and reliable, might as well try and walk. Of course, if one is headed to one of the districts further away, the calculation changes. But we will save those for future articles.

This article is featured in the March 26 edition of the Carnival of Cities, hosted by Family Travel.

Weekend Cat Blogging and more: Glass and metal

This weekend, Luna relaxes by the glass and metal table, just like she used to in our previous home:

Perhaps this is a good weekend to join some of our friends in Photo Hunters, as the theme this weekend is “metal.” Or “Easy like Sunday”, even though it's Saturday.


It looks like more of our friends are experiencing the joy that is moving one's home. Megan and the Bad Kitty Cats are moving. We wish them well. Samantha and Tigger have stepped in to host this weekend's Bad Kitty Cats Festival of Chaos.

This seems to be a rather mobile weekend, and the “cat boys” Kashim and Othello will host Weekend Cat Blogging #146 just as soon as they get back from their Easter trip.

The Carnival of the Cats will be also be this Sunday at Chey's Place. And of course, the Friday Ark is at the modulator.

Our thoughts this weekend are with the family of Smudge. He passed away this Friday.

The logistic function revisted

Today we revisit one of our most popular articles, on the logistic function:

f(x) = ax(x-1)

In the original article, we demonstrated how we can use this function as a “logistic map” by iterating (i.e.,applying it repeatedly to the previous result). The logistic map produced different sorts of behavior depending on the values of a. For example, for some values of a, iteration settles into a cycle, bouncing among two or more points on the function.

The original article provided more examples and more detail about the mathematics, and those who are interested are encouraged to go back and check it out. One of the main this we discussed was how one can characterize the logistic function over
different values of a using a graph called a bifurcation
diagram
. As the values of a increase (a is labelled as “r” in this graphic I shamelessly but legally ripped off from wikipedia), one can observe vertically the period doubling where the logistic map converges on a single value, then bounces between two points, then four, then eight, and so on, until the onset of chaos at approximately 3.57.

When a is greater than or equal to 4, the function “diverges”, i.e., it just gets bigger and bigger (or smaller and smaller because the numbers are negative) when you repeatedly apply it.

The bifurcation diagram shows what happens for real values of a, i.e., all integers, fractions and other numbers that can be expressed as a decimal. But suppose we allow a to be any complex number, or any combination of real and “imaginary” numbers (i.e., square roots of negative numbers). Real numbers can be expressed a line, while complex numbers are expressed on a plane. So we can produce an analog of the bifurcation diagram over a plane instead of a line as above.

In the following diagrams, we are looking at the complex plane of
different values for a. If the logistic map converges to either a single value or a cycle, the location on the plane is colored in black. If it diverges, i.e., gets infinitely farther away from zero, then the location is white. Unlike for real numbers, where the convergent “black” values of a form a simple line segment, for complex numbers the set of convergent values is a lot more “complex”:

Zooming in, we can see the structure of the set, with lots of smaller “bubbles” and “filaments” off of the main circles. The large circles are the complex-number equivalents of the single-line sections of the bifurcation diagrams, with the small bubbles representing cycles and period doubling.

Some readers might recognize similarities between this set and more well-known Mandelbrot set:

The similarity is more than coincidence, as the Mandelbrot set is based on a map similar to the logistic map. But the Mandelbrot set has the pronounced cardioid shape and asymmetry different from the logistic-map set. Zooming in further, we see that filaments and local areas of the two sets have more similarity. Indeed, we see small “Mandelbrot-like sets” at the junctions of the filaments:

It is interesting how these miniature versions have a shape similar to Mandelbrot set rather than the double-circle of the logistic-map set.

Although these sets have a “fractal-like” qualities, neither is a fractal in the strict sense of the word. They are not strictly self-similar, nor do they have fractional dimension. Nonetheless, we are featuring the logistic-map set as a “Friday Fractal” , an event started by our friend Andrée at meeyauw.

I am not sure the logistic-map set has a name like the Mandelbrot set has, so how about calling it the CatSynth set?

Submitted to Carnival of Mathematics #29.







Aquatic at Amazon


Well, it looks like my album Aquatic is available at Amazon. Or rather, via Amazon's MP3 download service. Amazon provides music for sale as straight MP3, with no DRM (Digital Rights Management) so that you can play them anywhere (and also copy them). Previously, the only way to get this and many other albums as DRM-free MP3s was to subscribe to a service like eMusic, or just steal them.

I did also notice that the album appears in Amazon Marketplace – in fact, a store in Santa Cruz is offering a used copy. That is itself a milestone, to find your own album in a used bin. That means someone who had a copy gave it up. Hopefully it's not because he or she disliked it. Indeed, I would prefer that they ripped it and continue to enjoy it (DRM-free, of course). It's not because I want people to steal music, but it is worth more to me just to know that people are listening…

Which brings us back to Amazon. I'm not expecting to sell a lot here, but it's great forum for feedback and comments, so I encourage anyone who has the album or individual tracks, legal or otherwise, to write a comment or review…